Keywords: Sterile insect technique (SIT)
As mosquitoes go year-round in L.A., a promising fix hits a snag
35516Lila Seidman, Los Angeles Times, 2026-03-23 09:06:38.
Residents were supposed to get a respite from the ankle-nipping mosquitoes that fueled a recent surge in dengue fever in Los Angeles County. Typically, the invasive mosquitoes — called Aedes aegypti — essentially disappear from winter until early May in the region. Instead, complaints to local agencies tasked with controlling the pests spiked recently. “We have not seen them go away altogether like they have in previous years,” said Susanne Kluh, general manager for the Greater Los Angeles County Vector Control District. Their unusual presence adds to the urgency of work going on in a 40-foot shipping container tucked away in Pacoima. It's about to transform into a bustling nursery for tens of thousands of mosquitoes. This May, the district is set for the third year in a row to release legions of sterilized male mosquitoes — which don't bite — into parts of Sunland-Tujunga. The last two years were promising, with the female population in two treated neighborhoods plunging by an average of more than 80%. Yet business owners have signaled they're not willing to pay to expand it. That's thrown uncertainty into officials' goal of eventually bringing the approach to their whole service area, spanning 36 cities and unincorporated communities. “Unfortunately, that's going to be a rather expensive endeavor,” said Steve Vetrone, an assistant general manager for the district. “I can tell you right now that's not something that we can do with our current operating budget.”
Mark–release–recapture study of irradiated male Aedes albopictus under stressful field conditions
35492Qingdeng Feng, Ming Li, Jeremy Bouyer, et al., Pest Management Science, 2026-03-09 10:33:54.
The sterile insect technique (SIT) suppresses mosquito populations by releasing sterile males. Its success mainly depends on the performance of sterile males. Mark–Release–Recapture (MRR) experiments are used to evaluate male performance in the field, yet most previous experiments were conducted under mild conditions (e.g. 25–28 °C) in which mosquitoes could easily adapt. Male mosquito performance under stressful field conditions remains poorly understood. This study evaluated the field performance of irradiated Aedes albopictus males under high-temperature conditions (>30 °C in average) in southern China, Foshan City, located in a sub-tropical area. Two MRR experiments were conducted in a 5-ha village during July–August of 2023 and 2024. Lifespan and dispersal of postreleased males were examined using BG-Sentinel mosquito traps, human landing catches, and ovitraps. A total of 54 546 and 58 440 sterile males were released in 2023 and 2024, respectively, with recapture rates of 8.53% and 5.64%. The mean dispersal distances ranged from 58.88–77.19 m (2023) to 81.82–90.86 m (2024). Daily survival probabilities were 0.15–0.28 in 2023 and 0.45–0.62 in 2024, corresponding to average expected lifespans of 0.53–0.78 days and 1.26–2.13 days, respectively. Estimated wild male densities ranged from 302–986 males ha−1 in 2023 to 416–3785 males ha−1 in 2024. Stressful field conditions severely reduced sterile male survival and dispersal, highlighting the need to optimize release protocols in challenging climates. These findings provide critical baseline data for advancing Ae. albopictus SIT programmes in southern China.
Present and Future of Mosquito-Borne Disease Control in Europe with a Specific Focus on the Mediterranean
35535Cholvi, M., Moretti, R., Osório, H. C., et al., Insects, 17. 2026-02-27 19:18:24.
Mosquito-borne diseases are an emerging public health challenge in Europe, driven by the spread of invasive mosquito species capable of sustaining outbreaks of tropical arboviral diseases. Rising temperatures, shifting precipitation patterns, human-driven habitat changes, and prolonged transmission seasons have increased the risk of dengue, chikungunya, and West Nile virus outbreaks, among other vector-borne diseases. Effective control requires a multifaceted approach, combining traditional and novel methods with advanced surveillance technologies and community involvement. However, growing insecticide resistance and concerns about insecticide use highlight the need for more prudent management of current tools and the development of innovative alternatives. Genetic control strategies, including the Sterile Insect Technique (SIT), Wolbachia-based approaches, and genetically modified (GM) mosquitoes, offer promising solutions but still face scientific, regulatory, and societal challenges. This review explores the current landscape of mosquito-borne disease control in Mediterranean Europe, emphasizing key challenges and emerging solutions. An integrated approach that strengthens surveillance, promotes sustainable control methods, and incorporates novel biotechnological tools supported by smart technologies will be essential to reduce the future burden of mosquito-borne diseases in the region.
Evaluation of local larval diets for mass rearing of Aedes aegypti to support sterile insect technique programs in Burkina Faso Get
35466Bouraïma Vincent Séré, Simon P Sawadogo, Prisca S L Paré, et al., Journal of Medical Entomology, 63. 2026-02-16 14:16:30.
Aedes aegypti Linnaeus 1762 is the primary vector of several viruses that cause arboviral diseases. Control strategies, such as SIT, require large-scale mosquito (Diptera: Culicidae) production, which depends critically on larval nutrition. However, the high cost and limited availability of conventional feed components hinder SIT implementation, particularly in resource-limited settings. Faced with this situation, it is imperative to find locally produced food sources. Here, we assessed six locally derived diets for their suitability in mass rearing Aedes aegypti. The diets include: (B) African Clarias gariepinus Burchell 1822 (Siluriformes: Clariidae) dried without additives; (C) Cirina butyrospermi Vuillet 1911 (Lepidoptera: Saturniidae) dried without additives; (D) Glycine max (L.) Merr., 1917 without additives; (E) a 1:1 mixture of Clarias gariepinus and Cirina butyrospermi; (F) a 1:1 mixture of Clarias gariepinus and Glycine max; and a mixture of 50% Clarias gariepinus, (G) 25% Glycine max and 25% Cirina butyrospermi. (A) Commercial fish food formulation (TetraMin® Baby) served as the control. Diets C and D were associated with significantly delayed while diets C, D, and E yielded fewer adults than the control. In contrast, diets B and G provided the most favorable balance of development time, adult emergence, and survival, comparable to the control group. Diets D and F produced the lowest fecundity and hatch rates, whereas diet G generated large, fertile adults. Collectively, these findings indicate that diets B and G are suitable for mass rearing, with diet G emerging as a cost-effective alternative for SIT programs targeting Aedes aegypti in Burkina Faso.
The evolution of the sterile insect technique from concept to global application
35432Kostas Bourtzis, Marc F. Schetelig, Walther Enkerlin, Rui Pereira, Comprehensive Molecular Insect Science, 5:180-211. 2026-02-10 12:07:51.
The sterile insect technique (SIT) is a species-specific, environment-friendly and cost-effective method for controlling insect pests and disease vectors. It involves colonization and mass-rearing of the target species, sterilization, typically by ionizing radiation, and systematic release of sterile insects, preferably males, into the target area. Released sterile males induce reproductive failure in wild populations, leading to suppression, containment, prevention of establishment, or local eradication of a target insect pest population. First demonstrated over a century ago, SIT has evolved into a robust and widely adopted tool within area-wide integrated pest management (AW-IPM) programs. It has been successfully applied against several major agricultural and veterinary pests, often achieving high returns on investment. In the context of accelerating climate change and global species invasions, further development and deployment of SIT are essential. Future efforts should focus on enhancing cost-effectiveness, operational scalability, and integration with complementary technologies for sustainable pest and vector management.
Generating cisgenic sexing strains in insect pests
35435Davydova, S., Liu, J., Kandul, N.P. et al., Communications Biology, 2026-02-05 18:20:56.
Insect pest population control via sterile insect technique markedly benefits from separation by sex prior to release. To simplify this process, traditional genetics has been deployed to develop genetic sexing strains (GSSs) for several disease vectors and agricultural pests of vast economic significance, although very few are applied in the field due to associated fitness costs and instability. In this study, we generated a method to engineer cisgenic GSS (CGSS) in insects. We use CRISPR/Cas9-mediated homology-directed repair to seamlessly translocate a sex-specific alternatively spliced intron into a dominant phenotypic gene generating a genetically stable strain that enables sex-sorting by eye. To achieve this feat, we use Ceratitis capitata as our model and relied on the sex-specifically spliced intron of its endogenous transformer gene, which we seamlessly inserted a copy into the pupal colouration white pupae gene. This minimal modification resulted in the generation of a homozygous strain we term IMPERIAL that was genetically and phenotypically stable where all female pupae are brown while male pupae are white with overall good fitness. By minimally editing the genome, our novel CGSS approach can be applied to other pests that may aid more efficient and economically suitable pest control.
Field implementation of the sterile insect technique against Aedes aegypti in Recife, Brazil: operational challenges and impact of release frequency on vector dynamics
35418Macedo, A.T., Carvalho, D.O., Gomez, M. et al., Infectious Diseases of Poverty, 15. 2026-02-02 16:59:43.
The sterile insect technique (SIT) is an environmentally friendly tool for suppressing Aedes aegypti populations. While promising in controlled settings, its application in large urban environments presents logistical and biological challenges. This trial focused on releasing sterile males, sent from a long-distance production facility to suppress the local mosquito population. Sterile males of Ae. aegypti were mass-reared, irradiated, and transported 712.2 km from a central facility to Recife, Brazil. Releases were performed once (SIT 1 ×) or twice per week (SIT 2 ×). Entomological indices—including eggs/trap per day (ETD), hatch rate, induced sterility, and adult female abundance—were monitored through ovitraps and BG-Sentinel traps. Data were analyzed using generalized linear mixed models (GLMMs) and Bayesian time-series modeling (CausalImpact). Dose–response experiments established that pupae required 35 Gy and adults 65 Gy to achieve > 99% sterility, with no difference between gamma and X-ray sources. Adult sterilization was effective across 24–96 h post-emergence, facilitating operational flexibility. Handling and transport reduced flight ability by up to 35 percentage points, highlighting cumulative stress effects. In field trials, SIT 1 × yielded limited suppression, with ETD values remaining similar to or higher than those of the control. In contrast, SIT 2 × produced consistent suppression, reducing ETD by 39%, hatch rate by 33%, and female abundance by 51%. In this study, increasing the release frequency was essential to achieve significant model outcomes, representing varying degrees of mild suppression of Ae. aegypti in a complex urban setting. In Addition, male handling, chilling, and transport emphasize the need to reduce the exposure to these parameters by improving the protocols. These results highlight key areas for scaling SIT within integrated vector management strategies in tropical urban settings.
Space Coast releases X-rayed skeeters to take bite out of dengue
35410Jim Waymer, Florida Today, 2026-01-29 10:40:25.
The Space Coast has unleashed 'nuked' skeeters in a new biological bid to neuter dengue fever. Last year, Brevard saw its first locally caught cases of the tropical disease and wound up with the most in Florida. In response, the county decided to let loose thousands of X-rayed male mosquitoes to zap the insect's next generation. Turns out an adult skeeter can survive X-ray doses more than 10 times what would kill humans. Unlike humans, once mature, most mosquito cells stop dividing, so radiation rushing through has fewer chances to distort most of its DNA. But X-rays will tear up the insect's reproductive genes enough to render the male mosquito sterile. That's among the reasons mosquito-control officials assure this time-tested method is safe and environmentally friendly. They emphasize that it's not anything like the much-more controversial gene modification of mosquitoes used in recent years in the Florida Keys. "When we're releasing, there's no voodoo," said Joe Faella, Brevard's mosquito control director.
Bisexual releases are as effective as male-only releases to control Drosophila suzukii with the sterile insect technique
35393Alexandra Labbetoul, Simon Fellous, Pest Management Science, 2026-01-23 10:16:56.
The sterile insect technique (SIT) suppresses insect reproduction by repeatedly releasing sterile insects and allowing them to mate with insects of the same species in the wild. While the classical SIT relies on sterile males mating with wild females, there is a debate regarding the risks and benefits of releasing sterile females along with the sterile males (i.e. bisexual releases). In a replicated cage experiment, we compared the effect of unisexual and bisexual sterile releases of Drosophila suzukii on induced sterility. To ensure field-realism, fertile females - wild-F0 freshly emerged from field-collected sweet-cherries - were placed in cages with artificial vegetation and plastic berries. The proportion of fertile females that produced offspring was not significantly different in unisexual and bisexual treatment (45% and 46%, respectively). Excluding females that had not mated (i.e. no sperm in the spermathecae) from the analysis had no influence. These results suggest the release of sterile females does not always affect the efficacy of the SIT. Even though additional phenomena may arise when scaling up from cages to the field, we conclude that sorting females with genetic constructs or robotic systems is probably dispensable in D. suzukii SIT, at least when deployed in confined farming systems.
Identification and evaluation of two testis-specific serine/threonine kinase genes from multi-tissue transcriptomes as potential genetic targets of sterile insect technique in Zeugodacus tau
35439Weijun Li, Cuikang Xu, Hongshi Chen, et al., Pest Management Science, 2026-01-15 18:32:40.
Zeugodacus tau (Walker) is a notorious agricultural pest causing significant economic losses in vegetable production for many years. Sterile insect technique (SIT) has emerged as an environmentally sustainable pest management strategy. However, discovery of molecular targets applicable for SIT implementation in Z. tau still constitutes a significant research gap. We conducted comparative transcriptome analysis of four male tissues (midgut, Malpighian tubules, fat body, and testis), identifying 9653 differentially expressed genes (DEGs) with predominant testis enrichment. Bioinformatics screening revealed 3020 testis-specific highly expressed genes showing significant functional enrichment in cytoplasmic translation, cytosolic ribosome assembly, and oxidoreductase activity. Quantitative real-time PCR (qRT-PCR) assay was utilized to confirm 10 testis-specific genes, including two serine/threonine kinases (ZtTSSK1 and ZtTSSK3) which were significantly enriched in spermatid development. Fluorescence in situ hybridization (FISH) localized the two genes specifically to the transformation zone of Z. tau testis. Functional characterization via RNAi bioassay demonstrated that suppression of ZtTSSKs expression levels reduced spermatozoa number and impaired male fertility. These results establish ZtTSSKs as crucial regulators of male fertility in Z. tau and identify them as potential molecular targets for developing SIT-based interventions against this economically significant pest.
Sterile insect technique reduces cabbage maggot (Diptera: Anthomyiidae) infestation in root crucifers in Canada
35337Anne-Marie Fortier, Allen Bush-Beaupré, Jade Savage, et al., Journal of Economic Entomology, 118:2710–2717. 2026-01-07 11:20:58.
The cabbage maggot (Delia radicum (L.)) is a major pest of brassica vegetables in Canada that has traditionally been managed with soil-applied insecticides. However, recent regulatory restrictions on key products such as chlorpyrifos have created a pressing need for alternative solutions. This study evaluates the sterile insect technique (SIT) as a control method for the cabbage maggot in root crucifers. Large-scale field trials conducted from 2019 to 2022 in Quebec (Canada) demonstrated significant reductions in D. radicum infestations in radish and daikon crops. Quality control measures confirmed the effectiveness of sterilization on cabbage maggot, with minimal impact on male performance. The results suggest that the SIT is a promising, environmentally friendly alternative to chemical control for cabbage maggot management. The study further highlights the importance of optimizing release strategies and improving predictive models to guide deployment. Overall, the SIT offers growers a viable option to reduce reliance on insecticides while maintaining crop health and yield.
Researchers develop temperature-controlled gene-editing method to potentially improve efforts to control disease-carrying insects
35356Caliann Ferguson, UT Health Houston School of Public Health, 2026-01-06 09:54:29.
New research presents promising results from an innovative technique that utilizes temperature control to genetically engineer sterile populations of insects, such as mosquitoes responsible for diseases like malaria, dengue, and other vector-borne illnesses. Led by researchers at UTHealth Houston School of Public Health, the Nature Communications publication leverages historical and traditional sterilization insect techniques (SIT) and applies an innovative method that can be scaled for larger population protection. Used for decades, traditional SITs include releasing large numbers of sterile males into mosquito populations so that when they mate with wild females, no viable offspring are produced. CRISPR/Cas9-based methods have proven challenging as they require breeding two separate lines of engineered insects and carefully sorting those insects to produce and release only sterile males. Led by principal investigator Victor Lopez Del Amo, PhD, assistant professor of epidemiology, and Christina Nguyen, a research technician, who carried out most of the experiments, this promising method aims to simplify the traditional SIT by harnessing a gene-editing tool called CRISPR-Cas12a that can generate male sterility and female lethality in a temperature-controlled manner. Cas12a can be engineered to be inactive at lower temperatures and active at higher temperatures. This property enabled the team to develop a single genetically modified insect strain that possesses the genetic composition necessary to disrupt key fertility and reproductive genes.
From song to stories: assessing the impact of exposure to arts-based community engagement tools in shaping knowledge, attitudes, and acceptability toward the Sterile Insect Technique for malaria control in South Africa
35319Manana, P.N., Jewett, S. & Munhenga, G., Malaria Journal, 24. 2026-01-05 11:31:18.
Community engagement (CE) is essential for public health interventions. This is particularly important when introducing novel technologies, such as the Sterile Insect Technique (SIT), that require strong community understanding and acceptance. Against this background, arts-based CE strategies, including music, drama, and radio short stories, were developed and piloted, but their effectiveness remained unevaluated. This study assessed whether exposure to arts-based CE approaches influenced community knowledge, attitudes, and acceptance of the SIT in uMkhanyakude District, KwaZulu-Natal, South Africa. A cross-sectional survey to understand the influence of arts-based CE approaches was conducted in the Jozini municipality, uMkhanyakude District, after community exposure to these CE productions. Structured interviews were conducted with randomly sampled community members. Data were collected on CE exposure and SIT-related knowledge, attitudes, and acceptance. A chi-square test and a stepwise ordinal logistic regression were used to analyze the data after adjusting for sociodemographic factors. Among 614 participants, only 26.2% (n = 161) were exposed to arts-based CE approaches. Those exposed were more likely to correctly identify that female mosquitoes feed on blood as compared to the unexposed (95.0% vs. 85.8%, p = 0.008), and to express support for SIT (e.g., 98.1% vs. 89.4% agreed with upcoming releases, p = 0.003). Exposure remained a significant predictor of SIT acceptance in multivariate models (OR 0.65, 95% CI 0.45–0.94). Positive attitudes and accurate knowledge also independently predicted greater acceptance. Arts-based CE tools were effective in supporting the introduction of SIT by improving knowledge and acceptance. However, limited exposure suggests the need for more sustained and widely accessible engagement strategies to maximize reach and long-term impact. These findings suggest that artistic productions, especially when delivered through culturally relevant, multimodal formats, play a meaningful role in shaping community receptiveness to novel vector control methods like the SIT.
A temperature-sensitive CRISPR-Cas12a system for sterile insect technique
35361Nguyen, C., Omotayo, A.I., Sanz Juste, S. et al., Nature Communications, 16. 2025-11-14 11:49:30.
The sterile insect technique (SIT) reduces population numbers by releasing sterile males that produce non-viable progeny. Specifically, CRISPR/Cas9-based precision-guided SIT (pgSIT) generates sterile males through genetic crosses of two transgenic lines: a Cas9 strain and a guide RNA (gRNA) strain targeting male sterility and female viability or infertility. However, pgSIT requires separate maintenance of the two lines and sorting to obtain sterile males, creating possible challenges for scaling. To overcome this, we propose using Cas12a nuclease, which is inoperative at lower temperatures but active at higher temperatures. Here, we develop a Cas12a-based pgSIT system involving a single strain containing both the Cas12a nuclease and gRNAs to induce male sterility and female lethality. This strain can be maintained as a mixed stock of both sexes and only activated by increasing temperature, producing sterile males after just one generation. By reducing the challenges that arise with maintaining two separate lines, this system could offer a scalable alternative for vector control in combating vector-borne diseases.
Synthetic biology approaches to generate temperature-sensitive alleles for the Sterile Insect Technique
35280Chun Yin Leung, Ernst A. Wimmer, Hassan M. M. Ahmed, Insect Science, 2025-11-03 11:22:09.
The Sterile Insect Technique (SIT) is an environmentally friendly, sustainable pest control approach, which uses large-scale releases of sterile insects to suppress or eradicate target populations through infertile matings. The efficiency of SIT is enhanced by male-only releases requiring genetic sexing strains (GSSs) that are classically based on selectable recessive visible markers or temperature-sensitive lethal (tsl) mutations and a rescue by a wild-type allele translocated to the male-determining chromosome. The transfer of identified or designed temperature-sensitive alleles might allow the generation of neoclassical GSSs in additional SIT target species. By using precise genome-editing tools, such as CRISPR/Cas, the creation of specific mutations in target genes and the integration of a wild-type copy is feasible without the introduction of foreign DNA. This might ease regulation of neoclassical GSSs, since they are not considered transgenic. However, integration and expression of genes at male-determining loci or chromosomes is not reliably established. Therefore, additional strategies to link temperature-sensitive phenotypes to female development are required, which could be achieved by targeting genes involved in dosage compensation or sex determination. To create temperature-sensitive alleles, rational protein design using advanced modeling and prediction tools to evaluate and tailor the effect of mutations on protein stability and temperature sensitivity can be used. In addition, emerging synthetic biology strategies such as temperature-inducible N-degrons or temperature-sensitive inteins provide powerful tools to generate temperature sensitivity. Such approaches should enable conditional control over proteins causing female lethality or sex conversion and therefore promise straightforward generic approaches to generate GSSs for male-only production in SIT target species.
Effect of male age at the time of irradiation on the sexual performance of sterile Ceratitis capitata males: insights from remating female offspring
35278Edwin Mauricio Ramírez-Santos, Pedro Alfonso Rendón Arana, et al., Insect Science, 2025-11-03 11:19:51.
The Sterile Insect Technique (SIT) is an effective strategy for controlling insect pests, such as the Mediterranean fruit fly (Ceratitis capitata, Wiedemann). The effectiveness of the SIT depends on the ability of the sterile males to mate and their capacity to induce sterility in wild females. This study evaluated how the irradiation age affects their sexual performance, measured by the outcome of female remating events. Males of the GSS VIENNA 8D53− were irradiated at eleven different ages, from 72 h before emergence (pupal stage) to 72 h after emergence (adult stage) and mated with wild females. These females were subsequently allowed to mate with fertile males from the fluorescent TSS VIENNA 8 1260. The presence of fluorescent offspring was used as indicator of second-male paternity. Results showed that males irradiated at post-emergence ages produced the lowest egg-to-pupae conversion rate, indicating a greater ability to prevent females from producing offspring after remating with a fertile male. In contrast, males irradiated at pre-emergence ages were associated with higher numbers of fluorescent offspring. Although no significant differences were found in mating competitiveness (RSI), the outcome of the remating showed differences in the effectiveness of initial matings. These findings highlight the importance of considering the age of flies at time of irradiation in mass-rearing protocols to enhance the efficacy of SIT programs targeting C. capitata and suggest that irradiating males later in their life cycle, such as adult stages or in pupae close to adult emergence, limit offspring if females remate with fertile males in the field.
Suitability of a chilled environmental box of the Precision X-RAD 320 cabinet style irradiator for the irradiation of mosquitoes and tsetse in the context of the sterile insect technique
35276Hanano Yamada, Bénéwendé Aristide Kaboré, Samar Eisa, et al., Journal of Economic Entomology, 2025-11-03 11:17:02.
A cabinet-style small animal X-irradiator outfitted with an environmental chamber which can provide a consistent, chilled environment during irradiation was tested to sterilize the human and animal disease vectors Aedes aegypti Linnaeus (Diptera: Culicidae), Anopheles arabiensis Patton (Diptera: Culicidae), Glossina palpalis gambiensis Vanderplank (Diptera: Glossinidae) in the frame of the sterile insect technique (SIT). The environmental chamber enables the irradiation of immobilized, compacted adult insects avoiding mechanical damage incurred by movement and, thereby, maintaining better insect quality. For the species tested, there was no significant difference in dose response when irradiating late-stage pupae or adults, and chilling at 7 °C did not affect irradiation outcome in terms of sterility induced. The X-irradiator was shown to be effective and suitable for the sterilization of these important target species of the SIT and offers a practical means to sterilize insects at the adult stage which require chilling for immobilization.
Impact of long-term mass-rearing on the genetic structure of tsetse fly Glossina palpalis gambiensis colonies
35273Kiswend-sida M. Dera, Soumaïla Pagabeleguem, Tito Tresor Melachio Tanekou, et al., Insect Science, 32. 2025-11-02 17:49:38.
Tsetse flies are the sole cyclic vectors of African trypanosomes, which cause human and animal African trypanosomiases in Africa. Tsetse fly control remains a promising option for disease management. The sterile insect technique (SIT) stands as an environmentally friendly tool to control tsetse populations. SIT requires the mass-rearing of competent sterile males to mate with wild females. However, long-term colonization might affect the genetic structure of the reared flies. This study investigated the genetic structure of four Glossina palpalis gambiensis colonies of different ages: two originating from Senegal (SEN and ICIRSEN) and two from Burkina Faso (CIR and IBD). Samples from these colonies were genotyped at ten microsatellite loci, followed by downstream population genetic analyses. The results show that the two colonies from Burkina Faso collected from close sites (∼20 km apart) over 45-year interval retained the same genetic background (FST_CIR∼IBD ≈ 0, P-value = 0.47). These flies were however, genetically different from those from the Senegal colonies (FST_CIR∼SEN ≈ 0.047; FST_IBD∼SEN ≈ 0.058, P-value = 10−4). Moreover, no significant difference was detected in the gene diversity of the CIR and IBD colonies, with HS values of 0.650 and 0.665, respectively. The inbreeding coefficient showed that all four colonies where under Hardy–Weinberg equilibrium, with FIS values of 0.026, 0.012, −0.064, and 0.001, for CIR, IBD, ICIRSEN, and SEN, respectively. Furthermore, no sign of a recent bottleneck was identified in tsetse samples from any of the four colonies. The results suggest that long-term mass-rearing of tsetse flies has no significant impact on their genetic background and diversity.
SIT-ia: A Software-Hardware System to Improve Male Sorting Efficacy for the Sterile Insect Technique
35267de la Vega, G., Smith, L., Soria-Mercier, L., et al., Insects, 16. 2025-11-02 17:34:18.
This research addresses a challenge in using the Sterile Insect Technique (SIT), an eco-friendly pest control method. For SIT to work, only sterile male insects can be released, but sorting males from females by hand is slow and laborious. The study introduces a new automated system called SIT-ia that uses artificial intelligence (AI) to quickly and accurately tell male and female flies apart. When tested on the spotted-wing drosophila (Drosophila suzukii), the system was 98.6% accurate. A key benefit is its speed: SIT-ia can sort 1000 flies in about 70 min, which is 40 min faster than human experts. This innovation makes sex-sorting a more efficient and practical process, needed for managing pest insects in a sustainable way. Invasive insects can cause significant economic impacts to agriculture worldwide and impact human health. Traditional pest management methods that include chemical insecticides have raised increasing environmental and health concerns, prompting the need for sustainable alternatives. The Sterile Insect Technique (SIT), which consists of releasing sterile males of a target pest to mate with wild females, is held as a promising solution. However, the success of SIT relies on the release of sterile males. The efficient separation of sexes prior to sterilization and release is necessary. This study presents SIT-ia, a software–hardware system that utilizes artificial intelligence (AI) and computer vision to automate the sex-sorting process. We showcase its use with the fruit fly pest D. suzukii. The system was able to identify males from females with a 98.6% accuracy, sorting 1000 sterile flies in ~70 min, which is nearly half the time involved in manual sorting by experts (i.e., ~112 min). This simple device can easily be adopted in SIT production protocols, improving the feasibility and efficacy of improved pest management practices.
Successful suppression of Aedes aegypti (Diptera: Culicidae) with the sterile insect technique also results in larger female mosquitoes
35257Katherine G Evans, Rachel Morreale, Steven Stenhouse, et al., Journal of Medical Entomology, 2025-10-27 11:04:27.
Sterile insect technique (SIT) is an effective method for controlling pests and has been increasing in popularity to control Aedes mosquitoes. SIT involves inundating an area with sterilized male mosquitoes to reduce egg hatch by reducing the number of fertile matings and ultimately the number of wild adults. Enacting mortality early in the larval life of Aedes mosquitoes can result in counter-productive effects due to reduced competition among developing larvae. SIT projects targeting mosquitoes have historically assessed effectiveness by monitoring egg or adult numbers, leaving out crucial information on what occurs at the larval stage. Our experiments involved collecting and hatching eggs from ovitraps in an SIT-treatment zone and 2 nearby non-SIT zones. We reared the resulting larvae in density and resource conditions similar to those in the field and compared numbers of emerging adults and sizes of emerging adult females from SIT and non-SIT zones. We hypothesize that the effectiveness of SIT in reducing adult populations is modified by density dependent mortality and density dependent growth among larvae. Our results indicate that SIT effectively suppressed the production of adult Aedes aegypti (L) in the SIT zone compared to non-SIT zones. Additionally, female Ae. aegypti, collected as eggs and reared in laboratory-simulated field conditions were significantly larger from the SIT zone than those from the non-SIT zones. Larger SIT-zone females are consistent with reduced intraspecific competition among larvae. Suppression of adult production in the SIT zone resulted in reduced predicted vectorial capacity, despite the increase in female size.
Intermittent releases: a modelling approach for sterile insect technique in mosquito control
35255Bhattacharyya, J., Banerjee, M. & Banerjee, S, Journal of Mathematical Biology, 91. 2025-10-27 10:49:16.
An unconventional and environmentally friendly mosquito management approach offers a sustainable solution that protects both the environment and human health. One such method is the Sterile Insect Technique (SIT), which holds promise as a mosquito control strategy by releasing sterilized male mosquitoes into the wild-type (WT) mosquito population. Since the success of SIT depends on the strategic planning of sterile mosquito releases, this paper examines a stage-structured model for mosquito populations with a density-dependent threshold for sterile male mosquito release, where releases occur only when the ratio of WT to sterile mosquito populations exceeds a critical threshold. Using intermittent releases, the proposed SIT model is designed to optimally align the release of sterile male mosquitoes with WT and sterile mosquito population densities, maintaining WT mosquito suppression at a predefined threshold and offering a more effective alternative to continuous release strategies. We employ Filippov’s modelling approach to investigate how intermittent releases, represented by piecewise-smooth functions, affect the dynamics of the system, particularly when mosquito populations exceed the predefined threshold. To explore the dynamical complexities, we employ Filippov’s convex method by defining the vector field in the discontinuous region as convex combinations of adjacent fields, allowing for the analysis of sliding motion and the identification of discontinuity-induced bifurcations through differential inclusions. Our findings identify the minimum release rate of sterile mosquitoes required to achieve the desired suppression level, highlighting the need to increase this rate due to increased WT mosquito immigration, reduced survival and mating fitness of sterile mosquitoes, and limitations in mosquito surveillance accuracy.
Dispersal and survival of gamma-irradiated Culex quinquefasciatus: Implications for sterile insect technique applications
35207Nungki Hapsari Suryaningtyas, Raden Wisnu Nurcahyo, Beni Ernawan, et al., Open Veterinary Journal, 15:3054-3062. 2025-10-02 14:51:05.
Culex quinquefasciatus is a major vector of filariasis and other mosquito-borne diseases. The sterile insect technique (SIT) has been widely used to suppress mosquito populations, but its effectiveness depends on the dispersal, survival, and competitiveness of sterile males. This study evaluated the dispersal range, survival rate, and recapture success of gamma-irradiated Cx. quinquefasciatus under field conditions. A mark-release-recapture (MRR) experiment was conducted using sterile male and female Cx. quinquefasciatus. Two release events were conducted, and recapture data were collected over seven days using BG-Sentinel-2 traps baited with octanol placed within a 250-m radius. The irradiated males traveled an average of 143.18 m (FR50: 92.78 m; FR90: 220.02 m), and the females dispersed 146.26 m (FR50: 95.26 m; FR90: 227.25 m). Dispersal distance was significantly influenced by release site in males (p = 0.0089) and females (p = 0.0042) but not by recapture day (p > 0.89). Recapture location significantly affected dispersal in both sexes (p < 0.0001). The daily survival probabilities of males and females were 0.88 and 0.69, respectively, with corresponding life expectancies of 7.57 and 2.71 days. The dispersal and survival of sterile Cx. quinquefasciatus are affected by release strategies. To optimize SIT, further studies should refine the marking techniques, explore a combination of trapping methods, and evaluate the dispersal patterns across varied landscapes. These findings offer valuable insights into improving the implementation of SIT for Cx. quinquefasciatus population control.
Estimated cost and operational structure of pgSIT malaria vector control programs in selected West African countries
35203William A.C. Gendron, Robyn Raban, Agastya Mondal, et al., Scientific African, 29. 2025-09-30 15:35:38.
Malaria control has primarily been achieved through vector control, but current methods are insufficient to achieve elimination. Precision guided sterile insect technique (pgSIT) is a mosquito suppression technique that generates sterile male mosquitoes for mass release. Our previous studies showed that this intervention is expected to be highly cost-effective in a malaria endemic region of West Africa, but these estimates used only 15-31% capacity for sex sorting, which is the limiting production step and a primary cost. We, therefore, determined the most cost efficient facility size by calculating the cost per million Anopheles gambiae suppressed as the facility was scaled up to suppress more mosquitoes. We developed an optimized facility size per 9.2 million mosquitoes suppressed, which can be a framework for scaling and increases the cost effectiveness of this intervention. The development of this intervention can potentially interrupt malaria transmission, strengthen local public health institutions, create manufacturing capacity, provide local jobs, and enhance regional health security capabilities that are more resilient to disruptions in supply chains and malaria investment.
The impact of sterile insect technique processes on the performance of tephritid flies
35190Mayren Sánchez-Rosario, Jorge Toledo, Walther Enkerlin, Insect Science, 2025-09-29 09:49:25.
The sterile insect technique (SIT) is a pest control method that has been successful in controlling various species of fruit flies of economic importance worldwide. However, SIT procedures can affect the performance of mass-reared sterile fruit flies, compromising the SIT effectiveness. This review aims to identify and analyze the adverse effects associated with each step of the SIT. Special emphasis is placed on identifying critical points in the SIT process that compromise the quality and highlighting the stages that require greater optimization to improve the effectiveness of the technique. We reviewed the main scientific findings that document the impact of domestication, mass-rearing, irradiation, handling, and release on the biology, ecology, behavior, and genetic makeup of sterile males, and how they affect the performance of sterile males under natural conditions, and the effectiveness of the SIT. Although all stages of the Sterile Insect Technique (SIT) impose some degree of compromise on insect performance, domestication and mass-rearing have the most profoundly negative impact on the field performance of sterile fruit flies. As the initial and most influential stages, they largely determine the overall quality and competitiveness of released insects, exerting a stronger impact than any subsequent SIT component.
Improvement of colony management in insect mass-rearing for sterile insect technique applications
35183Adly M.M. Abd-Alla, Anne Geiger, David Haymer, Insect Science, 2025-09-29 08:40:15.
Sterile Insect Technique (SIT) applications against major insect pests and disease vectors rely on the cost-effective production of high-quality sterile males. This largely depends on the optimal management of target pest colonies by maximizing the benefits provided by a genetically rich and pathogen-free mother colony, the presence of symbiotic microorganisms, and efficient domestication, mass-rearing, irradiation, and release processes. At the same time microbial (bacteria, fungi, microsporidia, and viruses) pathogen outbreaks should be minimized or eliminated, and the use of hazardous chemicals restricted. The optimization of the colony management strategies for different SIT target insects will ensure a standardized high-quality mass-rearing process and the cost-effective production of sterile males with enhanced field performance and male mating competitiveness. The aims of the Coordinated Research Project (CRP) were to develop best practices for insect colony management for the cost-effective production of high-quality sterile males for SIT applications against major insect pests and disease vectors through a multidisciplinary approach involving entomologists, geneticists, ecologists, microbiologists, pathologists, virologists, and mass-rearing experts.
Effect of egg irradiation on development and sterility of wild-type and Wolbachia trans-infected Aedes aegypti mosquito vectors
35170Kittayapong P, Ninphanomchai S, Thayanukul P, Limohpasmanee W, PLoS One, 20. 2025-09-26 13:56:46.
Sterile Insect Technique (SIT), Incompatible Insect Technique (IIT) or a combination of the two has become alternative promising vector control approaches. In order to apply these approaches, the targeted mosquitoes need to be sterilized and released. So far, the irradiation of mosquitoes has been conducted at the pupae or adult stages. In this study, we investigated the possibility of applying X-ray irradiation at the egg stage and also assessed the effect on the development and sterility of both wild-type and Wolbachia trans-infected Aedes aegypti mosquito vectors. The eggs of both wild-type and Wolbachia trans-infected lines were irradiated using X-ray at the doses of 1, 3, 5 and 7 Gy. Development of immature stages was observed. For wild-type Ae. aegypti, X-ray irradiation at the doses from 3 Gy decreased the development of the first-instar larvae and increased the development of the third-instar larvae but there was no effect on pupae. For Wolbachia trans-infected ones, a irradiation dose as low as 1 Gy could increase the development of the forth-instar larvae while an irradiation dose of 7 Gy induced significantly high mortality to the pupae (p < 0.05). To assess sterility, males and females that emerged from irradiated eggs were mated with the non-irradiated ones. Our results showed that an irradiation dose of 7 Gy significantly caused more than 90% sterility in both wild-type males and females (p < 0.05). However, this irradiation dose could be reduced to 5 Gy to sterilize both males and females infected with Wolbachia. Our findings revealed, for the first time, that applying a low-dose X-ray irradiation at the egg stage could sterilize both wild-type and Wolbachia trans-infected Ae. aegypti when they become adults. Egg irradiation could make the implementation of SIT, IIT or combined SIT/IIT for vector control much more feasible as the sterile eggs are easier to distribute and operate when compared to other developmental stages of mosquitoes.
SELECTING A LARVAL DIET FOR SCALABLE MASS-REARING OF AEDES AEGYPTI IN STERILE INSECT TECHNIQUE APPLICATIONS
35168Aryaprema VS, Blore K, Sypes O, et al., Journal of the American Mosquito Control Association, 2025-09-26 13:51:54.
Controlling Aedes aegypti populations through traditional methods is increasingly difficult due to the development of insecticide resistance and their use of cryptic breeding habitats. The sterile insect technique has emerged as an effective tool for integrated vector management. Still, its success depends on the ability to mass-rear large numbers of high-quality mosquitoes. Choosing an appropriate larval diet is crucial for scalable mass-rearing, as it directly influences mosquito development, survival, and overall production efficiency. This study compared the effects of 3 larval diets: 1) TetraMin® Tropical Flakes, 2) Ziegler® Tropical Pro-Start45 Meal, and 3) bovine liver powder delivered in cellulose capsules, on the growth and performance of male Ae. aegypti under simulated mass-rearing conditions. Ziegler-reared mosquitoes had significantly larger pupal and adult sizes than those reared on Tetramin or liver powder. The Tetramin diet produced smaller adults, but with longevity comparable to that of the Ziegler diet, whereas the liver powder diet resulted in mosquitoes of similar size to those of the Tetramin diet, but with reduced longevity. While all 3 diets demonstrated viability for mass-rearing, their suitability depends on program-specific goals and constraints. The liver powder diet offered a good balance of biological performance and operational efficiency, but at a substantially higher economic cost. With further optimization of feeding regimens, the Ziegler diet shows the most significant potential to deliver high biological quality at the lowest price, making it a strong candidate for scalable mass-rearing programs.
Suppression of Aedes albopictus in Sri Lanka using the Sterile Insect Technique (SIT) with a sustained effect
35157Menaka Hapugoda, Nilmini Silva Gunawardene, Tharaka Ranathunge, Sudath Samaraweera, K. Karunathilake, Bazoumana B.D. Sow, Gayan Parakrama Withanage, Indika Weerasinghe, Hamidou Maiga and Jeremy Bouyer, Parasite, 32. 2025-09-22 10:50:08.
Dengue fever remains a significant public health concern in Sri Lanka, leading to recurrent epidemics and imposing substantial socio-economic burdens. This study aimed to assess the efficacy of the Sterile Insect Technique (SIT) against Aedes albopictus (Skuse), the predominant dengue vector in the country, through a pilot field trial of an Integrated Vector Management (IVM) strategy including the SIT. The pilot trial was conducted in the Gampaha district, which reports the second-highest number of dengue cases in the country. A total of 3,300,000 sterile males, exposed to a 50 Gy radiation dose, were released over 33 weeks (100,000/week) within a 30-hectare release area. Entomological assessments were conducted at 115 trapping stations over a period of 71 weeks (October 2020–August 2022). Induced sterility of 98.16% in mosquito eggs was reached within the release area as compared to the control area (binomial generalized linear mixed model, deviance 2.408, df = 2, p = 0.016), indicating a notable impact of the SIT. The trial achieved nearly 98% suppression of adult vector mosquitoes, with a sustained suppression effect for 13 weeks post cessation of releases. These findings suggest that SIT can be effectively integrated as a potential additional tool into the future IVM strategy in Sri Lanka.
Fruit fly tests in Greece target invasive species threat
35161Vassilis Kyriakoulis, Phys.org, 2025-09-15 15:24:50.
In a small persimmon orchard in northern Greece, scientists carefully open paper bags to release thousands of flies, in an experiment aimed at blunting the destructive impact of invasive new species. The insects are sterile male Mediterranean fruit flies (Ceratitis capitata), a pest that annually causes significant damage to crops in Naousa, where a large proportion of Greece's prominent export, the peach, is produced. But the project is ultimately aimed at curbing an even greater threat: fruit fly species from Asia, which have begun to make their appearance in southeastern Europe as climate change increases local temperatures. The four-year, EU-funded project titled REACT brings together researchers from 12 different countries including the UK, Israel and South Africa. The program has a budget of 6.65 million euros ($7.8 million). "Our approach is to locally eradicate Mediterranean fruit fly populations and then apply this knowledge to other species of interest, such as the oriental fruit fly and the peach fruit fly," said project participant Nikos Papadopoulos, a professor of Applied Entomology at the University of Thessaly. The male flies are grown at the University of Patras and are fed a bacterial supplement that makes them more active, resilient, and competitive, said George Tsiamis, the university's Laboratory of Microbiology Systems director, during a media tour organized in Naousa by the research team.
Sequence and expression analysis of potential spermatogenesis-specific gene cognates in the Caribbean fruit fly, Anastrepha suspensa
35118Alfred M. Handler, Richard B. Furlong, Chao Chen, Daniel A. Hahn, Insect Science, 2025-09-08 08:26:08.
The sterile insect technique (SIT) is a highly effective biologically-based method for the suppression of many insect pest populations. SIT efficacy could be improved by methods of male sterilization that avoid the use of irradiation that can result in diminished fitness and mating competitiveness. Alternative sterilization methods include conditional disruption of genes for male fertility, or using their sperm-specific promoters to drive the expression of genes for lethal effectors. Testing has begun for the testis-specific β2-tubulin gene, though additional male fertility genes are required for redundancy or replacement, and for species where the β2-tubulin isoform does not exist or is not testis-specific. Here we had the goal of identifying and characterizing the sequence and transcriptional expression of two genes in the caribfly, Anastrepha suspensa, that are cognates of D. melanogaster spermatocyte-specific male fertility genes. In Drosophila, wampa encodes a coiled-coil dynein subunit required for axonemal assembly essential to microtubule-based sperm motility, while Prosα6T is a proteasome subunit gene required for spermatid individualization and nuclear maturation. In A. suspensa a cognate to wampa exhibited testis-specific transcript expression, which was minimal in both male and female body tissue. A Prosα6T cognate was not apparent in A. suspensa, but its constitutive isoform, Prosα6, expresses in male testes, but also in male and female body tissue. Thus, for A. suspensa, wampa remains a strong candidate gene for male sterility strategies for SIT including a direct target for gene-editing knockout and use of its promoter for testis-specific toxicity or cell death in conditional expression systems.
Development and evaluation of pupal color-based genetic sexing strains in Anastrepha obliqua
35116Daisy P. Cárdenas-Enríquez, Víctor García-Martínez, Jorge Ibáñez-Palacios, et al., Insect Science, 2025-09-08 08:23:07.
Anastrepha obliqua, a neotropical pest widely distributed in the Americas, attacks mango and other tropical fruits. In Mexico, it is controlled through integrated pest management, using the Sterile Insect Technique (SIT) as a main component. The applicability of SIT is significantly improved with the use of genetic sexing strains (GSS) that allow the possibility to release exclusively sterile males, the primary component of the technique. This study reports the isolation and characterization of two pupal mutations: black pupae (bp) and sphere pupae (sp), allowing for the first time the development of a genetic sexing system based on pupal color in this species. Inheritance analyses from reciprocal crosses between wild-type and mutant individuals showed F2 phenotypic segregation consistent with a recessive Mendelian inheritance pattern, and linkage analysis indicated that the bp and sp loci are in separate chromosomes. Using the bp mutation, two GSS were developed through gamma irradiation [T(Y;bp+)/bp-22](GSS-22) and ethyl methanesulfonate treatment [T(Y;bp+)/bp-354](GSS-354). Both GSS exhibited sex-specific pupal differentiation but displayed a high frequency of recombinants. Despite an initial reduction in biological fitness, GSS-22 demonstrated greater genetic stability and a lower frequency of recombinants than GSS-354. Discrepancies between cytogenetic and genomic data, particularly regarding the localization of the gene responsible for the black pupae phenotype, underscore the need to integrate polytene chromosome and genomic analyses to characterize these translocations and improve GSS stability precisely. These results represent a breakthrough in the creation of genetic tools for the management of A. obliqua control.
Application of Sterile Insect Technique (SIT) for Aedes albopictus (Skuse, 1895) in Sri Lanka: Dose optimization, mating competitiveness and release ratios
35114Harishchandra J, Abeyewickreme W, Premaratne R, Hapugoda M, PLoS One, 20. 2025-09-05 08:04:10.
Sri Lanka has experienced severe dengue epidemics in recent years, despite the extensive vector control measures taken. Therefore, it is necessary to find sustainable vector control strategies against dengue. Novel vector control tools need to be tested for the feasibility of applying them against local vectors. Sterile Insect Technique (SIT) is an increasingly popular vector control technique which has been adopted by many countries to suppress insect pest populations and is being tested for dengue vectors. In this study, SIT was developed for Aedes albopictus (Skuse, 1895), one of the 2 dengue vectors present in Sri Lanka. The optimum radiation dose for sterilizing male pupae (age 24–48 hours) using a Co 60 source was determined based on the post-irradiation pupal and adult survival in males and induced sterility in females at different doses. Further, the effect of irradiation on mating competitiveness of the selected mosquito strain was assessed under laboratory and semi-field conditions. The optimum release ratio of irradiated males to wild males was assessed in laboratory and semi-field settings. The optimum radiation dose was 50 Gy among the series of doses (25, 30, 40, 50, 60, and 70 Gy) tested. When pupae were exposed to the optimal radiation dose, 100% pupal survival, 19-day median adult survival time and 99% induced sterility resulted. A 5:1 ratio of irradiated males to non-irradiated laboratory-reared or wild males in laboratory cages resulted in induced sterility of 75% and 62%, respectively. The respective values were 74% and 61% in large semi-field cages. Fried Competitiveness Index (FCI) of irradiated males against wild males of laboratory and wild origin were 0.63 and 0.43 in laboratory cages and 0.57 and 0.55 in large semi-field cages. The males of Ae. albopictus irradiated at 50 Gy are adequately sterile and are competitive against the wild males. The release ratio of 5:1 irradiated males to wild males is a suitable ratio for the field application of SIT. The findings of the study will be important for the development of a protocol for future application of SIT for Ae. albopictus in Sri Lanka.
The shibirets4 mutation causes temperature sensitive paralytic and lethal phenotypes in the Queensland fruit fly, Bactrocera tryoni
35094Anzu Okada, Mamoru Okamoto, Thu N.M. Nguyen, et al., Insect Science, 2025-09-01 19:43:43.
Bactrocera tryoni, the Queensland fruit fly, is among the most damaging insect pests to the Australian horticultural industry as larvae infest ripening fruits or vegetables prior to harvest. Genetic biocontrol using Sterile Insect Technique (SIT) programs have been used to successfully suppress populations, via mass release of factory-reared sterile males that mate with wild females. Bi-sex flies are currently used for releases, although the efficiency of these control programs could be improved through using genetic sexing strains that eliminate females early during development, as they are not required for SIT. Here we used CRISPR/Cas9 mutagenesis to modify two nucleotides in the B. tryoni gene shibire, which created a proline to serine amino acid substitution and produced a temperature sensitive phenotype. Shibire is an essential GTPase required in endocytosis and synaptic vesicle recycling, and classical mutagenic screens in the vinegar fly Drosophila melanogaster previously identified temperature sensitive alleles including shits4 that results in adult paralysis. In B. tryoni, the shits4 mutant strain exhibited similar adult paralytic phenotypes when exposed to high temperatures, as well as temperature dependent lethality at egg, larval and pupal stages when subjected to heat treatment above standard rearing temperatures. These temperature sensitive phenotypes could be adapted to develop a SIT genetic sexing strain for conditional elimination of females prior to sterile releases, to improve efficiency and reduce costs.
Comparison of the standard and boosted sterile insect techniques for the suppression of Aedes albopictus populations under semi-field conditions
35085Marlène Dupraz, Renaud Lancelot, Gorgui Diouf, et al., Parasite, 32. 2025-08-28 18:38:54.
Innovative control tools are needed against Aedes mosquitoes. The boosted sterile insect technique (bSIT) consists of treating sterile males with a biocide prior to their release to contaminate larval habitats. We compared the efficacy of SIT and boosted SIT to prevent the emergence of adult Aedes albopictus in large cages. We tested two sterile-to-fertile male ratios: 5:1 (SIT5) and 1:1 (SIT1), with and without pyriproxyfen enhancement (bSIT or SIT). The eggs were collected in ovitraps and the immature stages were monitored until adult emergence or up to 15 days after hatching to estimate the relative risk (RR) of adult emergence compared to the control category. The concentration of pyriproxyfen in the ovitrap water did not change when sterile males were released with females or alone (χ2 = 0.99, df = 1, p = 0.547). This concentration was higher when the sterile-to-fertile male ratio was increased from 1:1 to 5:1: χ2 = 18.8, df = 1, p = 0.006. All four treatment categories were effective in suppressing mosquito populations. With a relative risk RR = 0.194 95% CI [0.128; 0.275], SIT5 was the most effective. Boosted SIT was not as effective as SIT. However, bSIT1 (RR = 0.418 [0.351; 0.492]) and bSIT5 (RR = 0.512 [0.431; 0.596]) were equally effective. Boosted males directly vectored pyriproxyfen to breeding sites. Boosted SIT was more effective than SIT alone with a low sterile-to-fertile male ratio. Under operational conditions, it could be initially deployed to suppress the target population and then switched to standard SIT.
Effectiveness of the sterile insect technique in controlling Aedes albopictus as part of an integrated control measure: evidence from a first small-scale field trial in Switzerland
35042Parrondo Monton, D., Ravasi, D., Campana, V. et al., Infect Dis Poverty, 14. 2025-08-24 16:54:24.
The invasive Asian tiger mosquito (Aedes albopictus) poses growing health risks across Europe. In Switzerland, a preliminary field trial was conducted to assess the feasibility of integrating the sterile insect technique (SIT) into existing integrated vector management (IVM), which includes breeding site removal and application of biological larvicides. SIT involves repeated releases of irradiated sterile males, which mate with wild females, producing non-viable eggs and leading to population decline. Following a preliminary release test in 2022, a small-scale SIT trial took place in 2023 in Morcote, Switzerland. Approximately 150,000 sterile males were released weekly over a 45-hectare area throughout the entire mosquito activity season, from May to September. This SIT area also received routine IVM. Population dynamics were compared with a control area where only IVM was applied. Monitoring included egg counts, hatch rates, and adult female densities. Generalized additive mixed-effects models (GAMM) and generalized additive models (GAM) accounted for spatial, temporal, and random effects. Model selection used AIC, BIC, and Chi-square tests (significance at 5%). The SIT-treated area showed a significant mosquito population reduction. Egg counts dropped by 57% (GAMM regression coefficient: − 0.8513, P < 0.001), with temporal patterns differing between SIT-treated and control areas (P < 0.001). Egg hatch rates were also lower in the SIT area, with odds of hatching reduced by 1.24 log-odds units (P < 0.001). Adult female densities declined by 66% (regression coefficient: − 1.0818, P < 0.001). Spatial GAMs revealed heterogeneous effects: up to 90% egg reduction in the western release area, while the eastern edge, bordering untreated zones, showed up to 300% higher egg counts. Similar spatial trends were observed for hatch rates and adult females (P < 0.01). These findings highlight both the overall effectiveness of SIT and the influence of mosquito immigration on spatial patterns. This trial demonstrated the potential of SIT as a complementary tool in Swiss vector control. Public interest and acceptance were high. To improve cost-effectiveness, further optimization of male production, sterilization, transport, and release processes is needed. Continued implementation over multiple seasons is recommended to enhance long-term effectiveness.
Spatiotemporal complexity in interacting wild and sterile mosquito populations
35005Mandal, G., Guin, L.N. & Chakravarty, S., Nonlinear Dyn, 2025-08-04 08:39:42.
In the present exploration, a mosquito population model is investigated that incorporates a non-linear, saturated release rate for sterile mosquitoes. The model framework leverages a reaction-diffusion system to generate spatiotemporal patterns. A thorough theoretical analysis is conducted to explore the model’s feasible equilibria, focusing on the phenomenon of bistability. Subsequently, the stability, instability, and potential bifurcation scenarios are examined rigorously. Each identified bifurcation is then utilized to elucidate the complex dynamical behaviour of the system. The entire parameter space is systematically partitioned by simultaneously varying two key parameters. This partitioned space can then be further analyzed in conjunction with one and two-parameter bifurcation diagrams. This approach facilitates a deeper understanding of the system’s dynamics within each identified region. In two dimensions (2D), the evolution of diffusion-driven pattern formation is presented for various scenarios, including spots, stripes, labyrinthine structures, combinations of stripes and holes, and hole replication. These spatial patterns are demonstrated to be influenced by critical system factors associated with the concept of Turing space. Sensitivity analysis reveals that the number of wild offspring produced per mating event is the most sensitive parameter within the model. Moreover, the present investigation admits dynamical codimension one and two bifurcations concerning the induced most sensitive parameter. The theoretical findings are consistently validated and corroborated by numerical simulations, which are further employed to evaluate the biological implications of the theoretical results.
Millions of genetically modified insects have been released in Brazil, but why didn’t anyone tell you about this before?
35003Noel Budeguer, Click Petroleo e Gas, 2025-08-04 08:29:56.
Few people realize, but Brazil is one of the most advanced countries in the world when it comes to biological pest control. Instead of relying solely on poisons and traps, Brazilian researchers are investing in technological solutions that, at first glance, seem like the stuff of science fiction: releasing modified mosquitoes and flies into the environment to prevent disease outbreaks and agricultural losses. The initiative may sound controversial, but it has already yielded impressive results—and, in some cases, may have prevented entire epidemics without anyone noticing. The logic behind these techniques is simple yet powerful. By releasing sterile or genetically modified males into the environment, they compete with natural males for females. When they win this contest and mate, the offspring born don't survive—or even hatch at all. The result is a drastic decline in the target pest's population. Two main approaches are used: the Sterile Insect Technique (SIT), which uses radiation to sterilize males, and genetic modification, which prevents reproduction through DNA alterations. Both methods eliminate the use of pesticides and have gained traction as sustainable and highly effective alternatives.
Threshold-dependent improvement in sex separation efficiency by NaCl pretreatment of larval–pupal mixtures in mass-reared Aedes albopictus
34996Yan Sun, Junyan Zhang, Keqing Zheng, et al., Pest Science Management, 2025-07-30 12:54:37.
The removal of female mosquitoes is a critical requirement in sterile insect technique (SIT) for mosquito control. Improving the efficiency and accuracy of sex sorting is therefore vital. Previous studies have demonstrated that treating larval–pupal mixtures with a 15% sodium chloride (NaCl) solution prior to the sex sorting process reduces female contamination in Aedes mosquitoes. However, the effects of NaCl on Aedes albopictus mosquito biology and its practical application in production facilities remain insufficiently explored and warrant further investigation. Exposure of larval–pupal mixtures to 15% NaCl for 60 min led to 100% larval mortality via osmotic imbalance and intestinal tissue damage, while pupae remained unaffected due to their impermeable cuticle. Males emerging from treated pupae exhibited comparable emergence, longevity, and flight ability to controls, indicating no adverse effect on male quality. NaCl pretreatment significantly improved sorting efficiency and reduced female contamination in manual sorting, achieving a 3.9-fold reduction in adult-stage contamination. Although automatic sorters increased throughput, reductions in female contamination were not statistically significant. Importantly, the sorting benefits of NaCl treatment were threshold-dependent and most evident at larger processing scales. NaCl pretreatment is a simple, scalable, and biologically safe strategy to enhance sex separation in Ae. albopictus mass production. It is particularly advantageous under high-throughput conditions and preserves male fitness, supporting the stringent quality standards required for successful SIT-based mosquito control.
Knowledge, attitude, and practice (KAP), and acceptance and willingness to pay (WTP) for mosquito-borne diseases control through sterile mosquito release in Bangkok, Thailand
34991Kittayapong P, Ninphanomchai S, Jalichandra N, Sringernyuang L, Sherer P, Meemon N, PLoS Negl Trop Dis, 19. 2025-07-30 11:03:04.
A questionnaire survey was conducted in seven communities in Bangkok, Thailand to obtain baseline information on knowledge, attitudes and practices (KAP) related to mosquito-borne diseases, i.e., dengue, chikungunya and Zika, including mosquito vectors and how to control them. The questionnaire also asked about the acceptance and willingness to pay (WTP) for sterile mosquitoes used in controlling mosquito populations. Our results showed that, from a total of 400 sampling households, about 85% of participants were familiar with dengue and its mosquito vectors, as well as their prevention and control. Furthermore, participants with lower ages and higher incomes had more knowledge on mosquito vectors (p < 0.05). Even though the majority of participants did not have any knowledge on sterile mosquito release, they showed a positive perception about it. However, more than half of them were not willing to pay for sterile mosquitoes, since they would like to receive them as public support from the government. If they were to pay, the cost that they could afford was 1–2 THB (~US$ 0.03- 0.06) per sterile mosquito. These findings should be useful for public health authorities when planning to apply the sterile mosquito release as an alternative mosquito control approach in Bangkok, Thailand.
Vector Control District Plans Experimental Mosquito Control Program
34982Contributing Editor, MyNewsLA.com, 2025-07-24 09:51:29.
Batches of irradiated male mosquitoes are slated for release Wednesday in Lake Elsinore with the goal of pairing the modified insects with as many females as possible to kill off the overall mosquito population, under an experimental program that apparently hasn’t generated concerns among public officials. The “Sterile Insect Technique Pilot Program” is being managed by the Northwest Mosquito & Vector Control District, which serves segments of western Riverside County. The district is believed to be the first countywide to inaugurate an SIT mosquito control program. Questions regarding when it was authorized, the estimated number of modified mosquitoes that will be released and any potential public health risks were not answered by the agency as of Tuesday afternoon. Lake Elsinore officials also did not respond to requests for comment. The West Valley Mosquito & Vector Control District, which encompasses Ontario, Montclair and neighboring municipalities in San Bernardino County, was the first district in California to receive authorization from state regulators to initiate mosquito SIT releases last year, under a pilot program similar to that of the Northwest Mosquito & Vector Control District. It’s still unknown whether West Valley’s experimental program has netted any benefits. “Sterile male mosquitoes are released to mate with local females, and the resulting eggs are unable to hatch,” NMVCD said in a statement regarding the Lake Elsinore program. “The release of adult male mosquitoes will not increase local bite pressure, as only female mosquitoes bite.”
Decoding and engineering temperature-sensitive lethality in Ceratitis capitata for pest control
34970R.A. Aumann, G. Gouvi, M. Gregoriou,T. Rehling, G. Sollazzo, K. Bourtzis, and M.F. Schetelig, Proceedings of the National Academy of Sciences, 122. 2025-07-10 10:38:52.
The Sterile Insect Technique (SIT) is a species-specific and environmentally friendly method for effectively controlling pest insect populations based on releasing reared, sterile insects into infested areas. Sex sorting in rearing facilities, enabling male-only releases, is necessary to ensure SIT programs are efficient, cost-effective and, in case of mosquito control, also safe. This can be greatly facilitated by genetic sexing strains (GSS), exhibiting sex-specific phenotypic markers. However, the development of GSS remains challenging. The construction of a temperature-sensitive lethal (tsl)-based GSS in the Mediterranean fruit fly (Ceratitis capitata) over three decades ago was considered a major breakthrough for SIT programs but was never successfully replicated in other pests. After over 30 y of research, we have pinpointed a specific mutation in the C. capitata lysine--tRNA ligase (Lysyl-tRNA synthetase, LysRS) gene responsible for the tsl phenotype. Introducing this specific mutation into a wild-type strain produced full embryonic lethality under heat stress, replicating the original mutant phenotype. The random integration of a LysRS minigene reversed this effect. The high conservation of LysRS among insects suggests that tsl-based GSS could be expanded to multiple pest species and extend applications of SIT programs for disease prevention and the protection of agriculture.
Genetic discovery advances insect pest control worldwide
34968IAEA, Phys.org, 2025-07-09 10:29:16.
An international research team led by Justus Liebig University Giessen (JLU) and the Joint FAO/IAEA Center of Nuclear Techniques in Food and Agriculture has identified the gene responsible for a temperature-sensitive lethality (tsl) phenotype in the Mediterranean fruit fly, solving a long-standing mystery. Their research is published in the Proceedings of the National Academy of Sciences. The sterile insect technique (SIT) involves the mass-rearing and sterilization using radiation of a target pest. Sterile males are then released over defined areas, where they mate with wild females, producing no offspring, which reduces the pest population. The SIT dates back to 1916, when scientists first used X-rays to induce sterility in insects. It was successfully implemented in the 1950s against the New World screwworm in the United States of America. Since then, SIT has become a globally recognized and target-specific method to suppress invasive and established insect populations of agriculture, veterinary and medical importance. The effectiveness and efficiency of SIT depends on reliably separating the sexes so that only sterile males are released in the field. A breakthrough came in the late 1980s with the discovery of the tsl mutation at the Joint FAO/IAEA Center's Insect Pest Control Laboratory. This was followed by the development of tsl-based genetic sexing in Ceratitis capitata, in which female offspring die at the embryonic stage following short-term heat treatment. This made it possible to produce sterile male flies at an industrial scale. Yet the gene underlying this effect remained unidentified for more than three decades, limiting the broader application of this approach to other insect species.
Modelling and sensitivity analysis to control dengue through inclusion of genetically modified hybrid mosquitoes
34907Wasim, T., Ismaeel, T., Naseem, A., Abdeljawad, T., & Alqudah, M. A., Mathematical and Computer Modelling of Dynamical Systems, 31. 2025-06-15 18:50:47.
Dengue fever, an ancient yet persistent global health threat transmitted by mosquitoes, remains difficult to control. Recent advances propose genetically modified hybrid mosquitoes as a novel intervention. This study focuses on two primary control strategies: the Sterile Insect Technique (SIT) and genetic sterilization. SIT involves releasing sterile male mosquitoes to reduce populations through unsuccessful mating, while genetic sterilization targets mosquito reproduction or virus transmission capabilities. In our proposed model, modified mosquitoes are included in the susceptible vector compartment, denoted as ℧𝑚. Diagnosis and treatment are modeled with parameters 𝑑1 and 𝑑2. Field and laboratory studies suggest these methods effectively reduce mosquito populations and dengue incidence. A mathematical model is developed to study this strategy’s impact, incorporating the basic reproduction number 𝑅0 and equilibrium analysis. Numerical methods are used to assess system stability and compute sensitivity indices 𝒲ℋ𝜉, ultimately demonstrating the potential for effective dengue control.
Evaluating the performance of three packing methods for long-distance transport of sterile adult Aedes albopictus males
34893Mamai, W., Puggioli, A., Wallner, T. et al., Scientific Reports, 15. 2025-06-06 08:21:38.
This study evaluated the performance of three packing methods for long distance transport of sterile adult Aedes albopictus males, considering the specific effects of pupal vs. adult irradiation and two compaction methods. The results indicated that while transportation significantly impacted the quality of sterile males, all the three packing methods (IAEA V.1.0, IAEA V.2.0, and CAA) tested under simulated transportation durations of 25–48 h resulted in average mortality rates below 12%, with male escape rates ranging between 30 and 50% after a 24-h recovery period. The transported males were able to survive for about 2 days under stress conditions. Additionally, adult irradiation led to higher male survival and escape rates than pupal irradiation, for both before and after transportation. The study also found that stacked cups were more effective as compaction method than the square plastic boxes, despite having a reduced maximum transport capacity. Providing sterile males with 10% sugar for a 24-h recovery period after transportation, also played a role in enhancing escape rate and survival. Although Ae. albopictus prove to be more sensitive to packaging and shipping procedures compared to Aedes aegypti, this study provides valuable insights for developing and improving handling packing and shipping guidelines.
The challenge of measuring mosquito flight performance: going beyond sterile insect technique and into transgenic and gene drive-based approaches
35311Paola Najera, Christian E. Ogaugwu, Tyler F. Chan, et al., Open Biology, 15. 2025-06-01 10:32:43.
Invasive insects inflict global costs of more than 70 billion USD annually by destroying crops and spreading disease-causing pathogens. Sterile insect technique (SIT), an insect population control method, involves the irradiation or chemical sterilization of insects to produce sterile males that are mass-released. SIT has proven effective in reducing populations of the Mediterranean fruit fly, Mexican fruit fly and screwworm fly. In the past decade, efforts to improve SIT with transgenic approaches have increased, including the development of potentially highly invasive gene drive transgenes. Determining flight capability is vital to the success of any insect control programme, and various flight assays can be used to analyse insect dispersal, flight behaviour and the mechanics behind flight. However, traditional flight assays such as mark–release–recapture become more challenging with transgenic or gene drive arthropods due to ecological concerns, while assays such as wind tunnels or flight mills/arenas may not capture the full range of flight abilities. This review seeks to cover current flight assays and their limitations as well as the requirements for flight assays to establish comparative flight ability for genetically modified insects to better prioritize strains prior to any potential field-based releases.
Optimizing larval mass-rearing techniques for Aedes mosquitoes: enhancing production and quality for genetic control strategies
34858Wadaka Mamai, Cécile Brengues, Hamidou Maiga, et al, Parasite, 32. 2025-05-26 20:56:36.
The quantity and quality of laboratory-reared insects are pivotal for the success of any sterile male-release program. Optimizing larval mass-rearing methods to enhance both production and quality in Aedes mosquitoes is essential to meet the growing demand from FAO/IAEA Member States for the sterile insect technique (SIT) as a component of area-wide integrated pest management to control or suppress disease vectors. This study was designed to identify the most effective feeding regime and schedule that maximize pupae production with a single tilt/sorting event and to evaluate an alternative larval-rearing unit. The results demonstrated that ingredient particle size, mosquito strain and feeding regime significantly influenced insect production and quality, underscoring the critical need to account for these factors in mass-rearing operations. A daily feeding regime of 0.17, 0.33, 0.67, 0.67 and 0.5 mg per larva was identified as optimal for both species (Ae. aegypti and Ae. albopictus) achieving up to 80 ± 2.5% male pupae recovery rate when sorted 48 h after the onset of pupation. Production outcomes were not compromised with the exclusion of feeding on Days 2 and 3. Furthermore, under the conditions of this study, the Wolbaki rack (Model WBK-P0003-V2) was shown to be sufficient for mass-rearing Aedes mosquitoes. Finally, a 4-day feeding regime was implemented in a field program on Reunion island, yielding similar pupae recovery rates and contamination as the reference regime, a significant step toward improving cost-efficiency and scaling-up the program. These findings provide valuable information for refining standard operating procedures (SOPs) for mass-rearing, thereby enhancing the efficiency and scalability of SIT programs.
Suppression of Aedes mosquito populations with the boosted sterile insect technique in tropical and Mediterranean urban areas
34854Bouyer, J., Gil, D.A., Mora, I.P. et al., Scientific Reports, 15. 2025-05-26 20:31:16.
Aedes mosquitoes are the vectors of dengue viruses and other arboviruses, which threaten billions of people all over the world. The boosted sterile insect technique (boosted SIT) is a version of SIT in which irradiated sterile males also transmit a biocide to immature stages. We describe three field trials that were run in 2021: one against Aedes aegypti in La Reunion and two against Aedes albopictus in Spain, each using pyriproxyfen as a biocide. The relative density of adults (compared to their density in control sites: without sterile male release) decreased from 1.00 to 0.09, 95% credible interval [0.06, 0.15] (La Reunion, July) and to 0.02 [0.01, 0.03] and 0.11 [0.08, 0.16] (Spain, July and October). The success rate, corresponding to the proportion of traps with suppression greater than 80%, ranged from 0.43 to 0.71 in La Reunion, from 0.26 to 1.00, and from 0.50 to 0.70 in Spain. In Spain, suppression with boosted SIT was higher than with non-boosted SIT, in 2020 and 2022. This work is in line with the predictions of the model of a better efficacy of boosted SIT compared to SIT, together with partial protection from invasion of treated areas by fertile females, paving the way for larger-scale field trials.
Advances in Sterile Insect Technique Driven by Sugarcane Pest Management in South Africa
34852Lawrence N. Malinga, Ph.D., and Samara Singh, Entomology Today, 2025-05-26 20:21:30.
Eldana saccharina, also known as the African sugarcane stalk borer, is an insect pest indigenous to Africa that targets gramineous crops such as sugarcane, maize (corn), sorghum, and millet in several countries, including Zimbabwe, Mozambique, Ethiopia, Ghana, Nigeria, and others. In South Africa, E. saccharina is the most damaging pest of sugarcane. The larvae feed internally on plant tissue, leading to a significant reduction in sugarcane yield. In South Africa, this damage amounts to over $60 million in annual revenue losses. In 1939, the first severe outbreak of this pest was recorded on sugarcane in South Africa. Since then, E. saccharina has spread throughout the sugarcane-growing areas of South Africa, affecting both coastal and inland regions (see map). Since the 1970s, the South African Sugarcane Research Institute (SASRI) has been actively involved in conducting research to control this pest. Over the years, attempts have been made to manage E. saccharina using a variety of control tactics, including insecticides, varietal resistance, biological control, and habitat management. A more recent control strategy is the sterile insect technique (SIT), which is currently in the proof-of-concept phase at SASRI.
Evaluating the impact on F1 sterility of tsetse pupae Glossina morsitans morsitans irradiated following short-term hypoxic conditioning
34848Caroline K. Mirieri, Kiswend-sida M. Dera, Vanessa S. Dias, et al, Insect Science, 2025-05-26 20:07:11.
The sterile insect technique (SIT) for tsetse involves releasing sterilized males to outcompete wild males in mating, resulting in nonviable progeny. Balancing optimum sterility and male quality is crucial. While irradiation in hypoxia or anoxia is routine for tephritid flies, its effect on tsetse, especially postrelease, is not well understood. We conducted experiments to understand the impact of irradiation in hypoxia on the sterility of the F1 generation of Glossina morsitans morsitans (Gmm). Initially, we tested the impact of 1-h preconditioning in hypoxia before irradiation and continued hypoxia up to 24, 48, and 72 h postirradiation on the emergence and flight propensity of treated males. We then assessed mating ability, survival, pupae per initial female (PPIF) and residual fertility of flies following irradiation at various doses after 1-h hypoxia conditioning. Finally, we determined the PPIF and residual fertility of the F1generation and the emergence of treated flies to the F2 generation. Results show that short-term conditioning (1 h) in hypoxia maintains or improves the qualities of the irradiated Gmm pupae. Regardless of irradiation in normoxia or hypoxia, higher residual fertility was observed in females than males in the F0 generation, and higher residual fertility in the F1 than the F0 generation for both sexes. However, the emergence rates of males decreased in the F2 generation compared with the F1 generation, a noteworthy finding for SIT programs for tsetse, implying diminishing populations of sterile flies.
Spiroplasma infection in colonized Glossina fuscipes fuscipes: impact on mass rearing and the sterile insect technique
34846Kiswend-sida M. Dera, Daouda Tande Barro, Bénéwendé Aristide Kaboré, et al, Insect Science, 2025-05-26 20:02:52.
Tsetse flies (Glossina spp.) can vector the parasites (Trypanosoma spp.) that cause the socioeconomically devastating neglected tropical diseases human and animal African trypanosomoses. In addition to this parasite, tsetse can harbor four genera of endosymbiotic bacteria, including Wigglesworthia, Sodalis, Wolbachia, and Spiroplasma, which are functionally crucial for the fly's physiological homeostasis and/or are potentially useful for the development of disease control strategies. Recent discoveries indicate that Spiroplasma infection negatively impacts tsetse fecundity. Conversely, housing the bacterium can benefit its fly host by making it unusually refractory to infection with parasitic African trypanosomes. In this study, we assessed the physiological impact of Spiroplasma infection on a laboratory colony of Glossina fuscipes fuscipes (Gff). For this purpose, two distinct Gff colonies were established: a Spi– colony that harbors a low Spiroplasma infection prevalence and a Spi+ colony that harbors a high Spiroplasma infection prevalence. Fitness parameters for both colonies revealed no significant differences in the length of larval development, adult eclosion rate, and flight propensity. However, flies from the Spi+ colony presented with lower fecundity and higher overall mortality than did individuals from the Spi– colony. Furthermore, males from the Spi– colony exhibited a competitive mating advantage over their Spi+ counterparts in a field cage setting. These findings have potential implications for the improvement of mass-rearing of Gff for sterile insect technique (SIT) applications.
Overview of the sterile insect technique for Aedes aegypti in Lee County, Florida, USA
34841Morreale, R., Stenhouse, S., Bajonero, J. et al., Infectious Diseases of Poverty, 14. 2025-05-12 20:10:08.
Lee County Mosquito Control District (LCMCD) is an independent taxing district that works to protect human health and improve quality of life in Lee County, Florida, USA. With local dengue transmission in southern Florida, LCMCD prioritized the control of Aedes aegypti. Due to the cryptic larval habitats of Ae. aegypti and insecticide resistance, effective control using conventional methods is difficult. Thus, the sterile insect technique (SIT) program, using X-ray irradiated male mosquitoes, was created to target Ae. aegypti. The goal of this program was to suppress Ae. aegypti through establishing a robust SIT program and performing a pilot study in the field to assess the impacts of SIT releases. The SIT program at LCMCD released sterile male Ae. aegypti from 2020 to 2022 in Captiva Island, Florida. The SIT program works within a larger Integrated Mosquito Management (IMM) framework and is not a standalone tool. The SIT program consists of nine employees, one of which is dedicated to quality assurance. Quality assurance assessments are performed routinely and periodically. Due to widespread destruction throughout Captiva and Sanibel Islands from Hurricane Ian in September 2022, the SIT pilot in Captiva Island was concluded and moved to Fort Myers, Florida. During the pilot study on Captiva Island, various lessons were learned and this knowledge has been applied to efforts in Fort Myers. LCMCD has established a successful SIT program to suppress populations of Ae. aegypti. Through connections with the International Atomic Energy Agency (IAEA) and the University of Florida, LCMCD received guidance from experts in the field to help ensure the program’s success. Stable funding through taxes levied specifically for mosquito control provided essential consistency, allowing the program to grow and evolve. Consistent trapping routines provided immense amounts of entomological data. Thoughtful and intentional community engagement was essential in ensuring acceptance of the SIT program in Lee County. Following the phased conditional approach suggested by IAEA, LCMCD has built an effective and resilient SIT program. The integration of the SIT as a tool of an area-wide mosquito control program is a feature that distinguishes LCMCD’s SIT program from others.
Functional validation of a white pupae minimal gene construct in Ceratitis capitata
34835Lucas Henrique Figueiredo Prates, Roswitha A. Aumann, Inga Sievers, et al., Insect Science, 2025-05-12 19:41:58.
Genetic sexing strains (GSS) are important tools for the sterile insect technique (SIT), an environmentally friendly and species-specific insect pest control method. GSS feature sex-specific phenotypes, enabling sex sorting in mass-rearing facilities and male-only releases, which significantly improve the cost-effectiveness and efficiency of SIT programs. In classical GSS, sex linkage of marker gene(s), such as white pupae (wp), is achieved through an irradiation-induced translocation between the marker-carrying autosome and the Y chromosome. However, this approach may render GSS males semisterile. The recently proposed neo-classical GSS concept suggests using genome editing to achieve sex linkage by directly inserting the wild-type marker allele onto the Y chromosome, potentially yielding GSS males with higher fertility. In this study, we examined the Ceratitis capitata wp gene as a genetic marker for the neo-classical GSS concept and developed a minimal, intronless version of this gene, termed mini-wp. We demonstrate that a single copy of mini-wp is sufficient to restore the wild-type brown puparium phenotype and is functional when integrated at various positions within the C. capitata genome, including the X chromosome. Due to its smaller size (4689 bp, including 2000 bp of putative promoter region) relative to the full wild-type wp allele (20868 bp), mini-wp may facilitate its precise insertion into the Y chromosome, representing an important step toward realizing neo-classical GSS. Furthermore, the methodology developed for designing and testing mini-wp in medfly may be adapted to other Tephritid species with an identified wp gene.
Impact of sterile Aedes aegypti males releases on vector dynamics: insights from Malaysian field trials
34815Nazni, W.A., Teoh, GN., Nuradila, M.A. et al., Infectious Diseases of Poverty, 14. 2025-05-04 16:00:48.
The Sterile insect technique (SIT) has been successfully used in agricultural pest control, leading to interest in its application for public health, particularly in controlling Aedes mosquitoes in the USA, Italy, Cuba, and Greece. Malaysia has conducted a small-scale SIT pilot trial since 2019 for dengue control. This study evaluates mosquito populations in treated and untreated sites through three objectives: (1) comparing mean larvae per trap (MLT) and dengue cases for Ae. aegypti and Aedes albopictus; (2) estimating survival rates and wild populations using mark-release-recapture (MRR); and (3) analysing spatial distribution in treated and untreated sites. Ae. aegypti males, irradiated at 55 Gray, were released in three locations: Pangsapuri Kota Laksamana (KT), Malacca (19 months), Pangsapuri Taman Tasik Utama (TTU), Malacca (8 months), and the Customs, Immigration, and Quarantine Complex (CIQ), Johor (7 months). Statistical analyses assessed SIT effectiveness, including T-tests for larval density and ovitrap indices, Mulla’s formula and relative variance (RV) for population reduction, and the Lincoln Index for estimating wild male populations and probability of daily survival. Weekly releases of sterile Ae. aegypti males at doses of 1278–7942 males/ha achieved a sterile-to-wild male ratio of 5.85 and a mean daily survival rate of 0.61, leading to significant reductions in larval densities: 76.25% in Kota Laksamana (KT), 96.74% in Taman Tasik Utama (TTU), and 89.00% in CIQ Gelang Patah, thereby supporting dengue control efforts. In KT, the MLT was initially low but increased, although with suppression < 90%, there was a reduce of dengue cases throughout the release period. The MRR’s mean survival rate (± standard deviation) in KT was 0.61 (± 0.08). The spatial clustering of Ae. aegypti was observed in central blocks during the high MLT period. However, larval densities rebounded after releases ceased. Spatial clustering revealed no initial clustering, though clustering patterns emerged over time in KT. SIT effectively suppressed Ae. aegypti populations and supported dengue control. Optimizing sterile-to-wild male ratios, spatial distribution, and monitoring strategies is essential for sustainable vector control. These findings provide insights for scaling up SIT field trials, with future efforts focusing on refining release and monitoring strategies to enhance SIT as an effective dengue control tool. Trial registration NMRR-17–2652-39,099 “Field evaluation of Sterile Insect for Aedes aegypti Suppression.”
A comparative assessment of self-limiting genetic control strategies for population suppression
34572Yue Han, Jackson Champer, Molecular Biology and Evolution, 2025-03-12 16:21:17.
Genetic control strategies are promising solutions for control of pest populations and invasive species. Methods utilizing repeated releases of males such as Sterile Insect Technique (SIT), Release of Insects carrying a Dominant Lethal (RIDL), self-limiting gene drives, and gene disruptors are highly controllable methods, ensuring biosafety. Although models of these strategies have been built, detailed comparisons are lacking, particularly for some of the newer strategies. Here, we conducted a thorough comparative assessment of self-limiting genetic control strategies by individual-based simulation models. Specifically, we find that repeated releases greatly enhance suppression power of weak and self-limiting gene drives, enabling population elimination with even low efficiency and high fitness costs. Moreover, dominant female sterility further strengthens self-limiting systems that can either use gene drive or disruptors that target genes without a mechanism to bias their own inheritance. Some of these strategies are highly persistent, resulting in relatively low release ratios even when released males suffer high fitness costs. To quantitively evaluate different strategies independent from ecological impact, we proposed constant-population genetic load, which achieves over 95% accuracy in predicting simulation outcomes for most strategies, though it is not as precise in a few frequency-dependent systems. Our results suggest that many new self-limiting strategies are safe, flexible, and more cost-effective than traditional SIT and RIDL, and thus have great potential for population suppression of insects and other pests.
Dissecting The Sterility Phenotype Of Drosophila Suzukii Males
34489Evrim Ağacı, The Pinnacle Gazette, 2025-02-04 17:43:46.
Groundbreaking findings on gene-edited males provide insights for pest management strategies. Researchers have made significant strides in controlling the invasive fruit pest Drosophila suzukii, commonly known as the spotted wing drosophila, utilizing innovative genetic engineering techniques to generate sterile males. This development could offer growers much-needed relief as traditional pest control methods face increasing challenges. Drosophila suzukii, native to East Asia, poses substantial threats to soft fruits, including strawberries and blueberries, by laying their eggs directly within the fruits, leading to damage and economic losses for farmers. With insecticide resistance on the rise and grower reliance on chemical management becoming less sustainable, there is urgent demand for novel pest control strategies. One promising approach is the precision-guided Sterile-Insect Technique (pgSIT), which employs CRISPR-based technology to develop sterile males efficiently. Unlike traditional Sterile-Insect Techniques, which involve labor-intensive processes like sex sorting and radiation to sterilize males, pgSIT simplifies the method and reduces costs by creating sterile males without offspring. The recent study, published on February 1, 2025, by researchers affiliated with Agragene Inc., aimed to dissect the sterility phenotype of these genetically modified males. It was found through multiple experiments and rigorous testing processes, including mating trials with wildtype females, determining the absence of mature sperm and the lack of genetic material transfer during mating.
Life-history traits of a fluorescent Anopheles arabiensis genetic sexing strain introgressed into South African genomic background
34435Nonhlanhla L. Ntoyi, Thabo Mashatola, Jérémy Bouyer, Carina Kraupa, Hamidou Maiga, Wadaka Mamai, Nanwintoum, Bimbile‑Somda, Thomas Wallner, Danilo O. Carvalho, Givemore Munhenga and Hanano Yamada, Malaria Journal, 21. 2025-02-03 06:44:24.
South Africa has set a mandate to eliminate local malaria transmission by 2023. In pursuit of this objective a Sterile Insect Technique programme targeting the main vector Anopheles arabiensis is currently under development. Significant progress has been made towards operationalizing the technology. However, one of the main limitations being faced is the absence of an efficient genetic sexing system. This study is an assessment of an An. arabiensis (AY‑2) strain carrying the full Y chromosome from Anopheles gambiae, including a transgenic red fluorescent marker, being introgressed into a South African genetic background as a potential tool for a reliable sexing system. Adult, virgin males from the An. arabiensis AY‑2 strain were outcrossed to virgin females from the South African, Kwazulu‑Natal An. arabiensis (KWAG strain) over three generations. Anopheles arabiensis AY‑2 fluorescent males were sorted as first instar larvae (L1) using the Complex Object Parametric Analyzer and Sorter (COPAS) and later screened as pupae to verify the sex. Life history traits of the novel hybrid KWAG‑AY2 strain were compared to the original fluorescent AY‑2 strain, the South African wild‑type KWAG strain and a standard laboratory An. arabiensis (Dongola reference strain). Results: The genetic stability of the sex‑linked fluorescent marker and the integrity and high level of sexing efficiency of the system were confirmed. No recombination events in respect to the fluorescent marker were detected over three rounds of introgression crosses. KWAG‑AY2 had higher hatch rates and survival of L1 to pupae and L1 to adult than the founding strains. AY‑2 showed faster development time of immature stages and larger adult body size, but lower larval survival rates. Adult KWAG males had significantly higher survival rates. There was no significant difference between the strains in fecundity and proportion of males. KWAG‑AY2 males performed better than reference strains in f light ability tests. The life history traits of KWAG‑AY2, its rearing efficiency under laboratory conditions, the preservation of the sex‑linked fluorescence and perfect sexing efficiency after three rounds of introgression crosses, indicate that it has potential for mass rearing. The potential risks and benefits associated to the use of this strain within the Sterile Insect Technique programme in South Africa are discussed.
Animal trypanosomosis eliminated in a major livestock production region in Senegal following the eradication of a tsetse population
34426Momar Talla Seck, Assane Guèye Fall, Adji Marème Gaye, Geoffrey Gimonneau, Mamadou Ciss, Mame Thierno Bakhoum, Baba Sall, Mireille Djimangali Bassène1, Renaud Lancelot, Marc J.B., Vreysen, and Jérémy Bouyer, Parasite 31, 31. 2025-02-03 04:43:45.
African animal trypanosomosis (AAT) was one of the main disease-related constraints to the development of intensive livestock production systems in the Niayes region of Senegal, a 30 km wide strip of land along the coast between Dakar and Saint-Louis. To overcome this constraint, the Government of Senegal initiated an area-wide integrated pest management programme combining chemical control tactics with the sterile insect technique to eradicate a population of the tsetse fly Glossina palpalis gambiensis Vanderplank, 1949 (Diptera, Glossinidae) in this area. The project was implemented following a phased conditional approach, and the target area was divided into three blocks treated sequentially. This study aims to assess the temporal dynamics of the prevalence of Trypanosoma spp. during the implementation of this programme. Between 2009 and 2022, 4,359 blood samples were collected from cattle and screened for trypanosomes using both the buffy coat and ELISA techniques, and PCR tests since 2020. The seroprevalence decreased from 18.9% (95%CI: 11.2–26.5) in 2009 to 0% in 2017–2022 in block 1, and from 92.9% (95%CI: 88.2–97) in 2010 to 0% in 2021 in block 2. The parasitological and serological data confirm the entomological monitoring results, i.e., that there is a high probability that the population of G. p. gambiensis has been eradicated from the Niayes and that the transmission of AAT has been interrupted in the treated area. These results indicate the effectiveness of the adopted approach and show that AAT can be sustainably removed through the creation of a zone free of G. p. gambiensis.
Assessing Radiation-Induced Enzyme Activation in Aedes aegypti: Potential Challenges for SIT-Based Vector Management
34370Edvane Borges da Silva, Sloana Giesta Lemos Florêncio, Ademir Amaral, et al., Acta Tropica, 261. 2025-01-28 14:35:08.
This study characterizes the Aedes aegypti population from Fernando de Noronha Island, Pernambuco, Brazil, prior to implementing the Sterile Insect Technique (SIT). The main objective was to assess changes in glutathione S-transferase (GST) enzyme activity, previously linked to cypermethrin resistance in this population, in 2010. GST activity was measured in both male and female mosquitoes, mass-produced in the lab, after exposure to ionizing radiation. The population evaluation after six years showed complete susceptibility to cypermethrin, deltamethrin, and lambda-cyhalothrin, although GST activity remained altered, increasing further following irradiation (50% higher in irradiated males and 31% higher in irradiated females compared to non-irradiated controls). This stress response to gamma radiation suggests implications for the effectiveness and viability of sterile males, particularly when SIT is combined with chemical insecticides. These findings enhance our understanding of radiation's impact on metabolic responses of the sterile males and provide valuable insights for refining integrated control strategies in vector management programs.
Recommendations for Implementing Innovative Technologies to Control Aedes aegypti: Population Suppression Using a Combination of the Incompatible and Sterile Insect Techniques (IIT-SIT), Based on the Mexican Experience/Initiative
34247Martín-Park, A., Contreras-Perera, Y., et al., Insects, 15:987. 2025-01-13 11:41:22.
The future of Aedes aegypti control emphasizes the transition from traditional insecticides toward more sustainable and multisectoral integrated strategies, like using Wolbachia-carrying mosquitoes for population suppression or replacement. We reviewed the integration of the successful Mexican initiative, “Mosquitos Buenos”, with the key challenges outlined in the PAHO guidelines for incorporating innovative approaches into vector control programs. These challenges include establishing essential infrastructure, training personnel, managing field operations, and fostering community support. Our experience provides critical evidence to support the strategic National Plan for implementing and integrating IIT-SIT technologies to control Ae. aegypti and dengue. Furthermore, this experience serves as a foundation for other countries in the region interested in adopting these technologies. It underscores the importance of strategic planning, multisectoral collaboration, continuous evaluation, and scaling up innovative tools to ensure their long-term effectiveness and sustainability in urban areas where Aedes vectors and the diseases they transmit are endemic.
‘Toxic Male Technique’ promises faster biocontrol of mosquito populations
34223Macquarie University, Phys.org, 2025-01-07 20:57:52.
A new biological pest control method that targets the lifespan of female insects could significantly reduce the threat of insect pests such as disease-carrying mosquitoes by offering faster and more effective results than current methods. Described in Nature Communications, the technique developed by researchers in Applied BioSciences and the ARC Center of Excellence in Synthetic Biology at Macquarie University is a new approach called the Toxic Male Technique (TMT). It works by genetically engineering male insects to produce insect-specific venom proteins in their semen. When these males mate with females, the proteins are transferred, significantly reducing female lifespan and their ability to spread disease. Insect pests pose a growing threat to global health and agriculture, causing hundreds of thousands of deaths, millions of infections, and costing billions in health care and crop damage annually. In mosquitoes like Aedes aegypti and Anopheles gambiae, only the females bite and transmit diseases such as malaria, dengue, Zika, chikungunya disease and yellow fever. Pesticides face declining effectiveness due to resistance and have caused harm to non-target species and ecosystems. Genetic biocontrol has emerged as a promising alternative. Current techniques like the Sterile Insect Technique (SIT) or insects carrying lethal genes (RIDL) work by releasing massive numbers of sterilized or genetically modified males to mate with the wild females. While these mated females produce no offspring or only male offspring, they continue to blood-feed and spread disease until they die naturally—meaning populations of biting females only decrease when the next generation emerges. By immediately reducing the biting female population, TMT offers significant advantages over competing genetic biocontrol methods. "As we've learned from COVID-19, reducing the spread of these diseases as quickly as possible is important to prevent epidemics," says lead author Sam Beach.
Biotechnology-enhanced genetic controls of the global pest Drosophila suzukii
33392Ying Yan, Hassan M.M. Ahmed, Ernst A. Wimmer, et al., Trends in Biotechnology, 2024-11-04 17:35:39.
Genetic control is a biological control method that introduces traits that sterilize, kill, or modify the population via intraspecific mating. Therefore, it is regarded as a species-specific and environmentally friendly management option for pest species. Spotted wing Drosophila (SWD) is an ideal insect model for studying genetic control strategies due to its pest status, laboratory-friendly biology, and close relationship to Drosophila melanogaster, which has abundant genetic resources. Different biotechnology-enhanced genetic control strategies of SWD are featured. The working schematics, control efficacies, some resistance mechanisms, and possible future development of these strategies are described. The designs and experience from these studies aid in the sustainable control of SWD and serve as essential references to other insect pests of economic or public health importance.
Pest control gets the CRISPR treatment
33376Seydel, C., Nature Biotechnology, 2024-11-04 13:45:02.
In June 2024, the St. Louis–based pest control company Agragene released genetically modified fruit flies on berry farms in California and Oregon, moving the technology out of the laboratory and into contained field testing. The trial marked a milestone for a next-generation biocontrol technology called the precision-guided sterile insect technique, or pgSIT. “The spotted wing drosophila (SWD) is the number 1 problem for any kind of strawberry, blueberry, raspberry, blackberry grower,” said Bryan Witherbee, president and CEO of Agragene. The flies have developed resistance to conventional chemical pesticides, and fruit growers suffer enormous economic losses due to the pest. “Growers are crying out for new tools,” Witherbee said. Hope is on the horizon, not only for farmers battling SWD and other agricultural pests but also for public health agencies struggling to control disease vectors. Several companies, including Agragene, are bringing biological pest control into the CRISPR era with pgSIT and other molecular tools that can specifically target the pest without killing beneficial insects, polluting the water or blanketing communities with toxic airborne chemicals. San Diego–based Synvect is applying pgSIT to disease-causing mosquitoes. Meanwhile, Oxitec, which has already successfully commercialized its “Friendly” genetic modification platform in mosquitoes, is turning its attention to crop pests.
Fluorescent-based sex-separation technique in major invasive crop pest, Drosophila suzukii
32544Junru Liu, Danny Rayes, Minzhe Yang, Omar S. Akbari, bioRxiv, 2024-10-09 12:30:05.
Insect population biocontrol methods such as the sterile insect technique (SIT), represent promising alternatives to traditional pesticide-based control applications. To use these strategies efficiently requires scalable sex separation techniques which are currently lacking in Drosophila suzukii, a prominent crop pest species. Having previously characterized a fluorescence-based sex-sorting technique in other pests, termed SEPARATOR (Sexing Element Produced by Alternative RNA-splicing of A Transgenic Observable Reporter), here we explore its potential applicability to Drosophila suzukii. Here, we engineer several strains of Drosophila suzukii encoding SEPARATOR constructs that allow for efficient sex selection in early larval stages.
Loss-of-function in testis-specific serine/threonine protein kinase triggers male infertility in an invasive moth
32506Wei, Z., Wang, Y., Zheng, K. et al., Communications Biology, 7. 2024-10-08 09:10:05.
Genetic biocontrol technologies present promising and eco-friendly strategies for the management of pest and insect-transmitted diseases. Although considerable advancements achieve in gene drive applications targeting mosquitoes, endeavors to combat agricultural pests have been somewhat restricted. Here, we identify that the testis-specific serine/threonine kinases (TSSKs) family is uniquely expressed in the testes of Cydia pomonella, a prominent global invasive species. We further generated male moths with disrupted the expression of TSSKs and those with TSSKs disrupted using RNA interference and CRISPR/Cas9 genetic editing techniques, resulting in significant disruptions in spermiogenesis, decreased sperm motility, and hindered development of eggs. Further explorations into the underlying post-transcriptional regulatory mechanisms reveales the involvement of lnc117962 as a competing endogenous RNA (ceRNA) for miR-3960, thereby regulating TSSKs. Notably, orchard trials demonstrates that the release of male strains can effectively suppress population growth. Our findings indicate that targeting TSSKs could serve as a feasible avenue for managing C. pomonella populations, offering significant insights and potential strategies for controlling invasive pests through genetic sterile insect technique (gSIT) technology.
Current status of the sterile insect technique for the suppression of mosquito populations on a global scale
32019Bouyer, J., Infectious Diseases of Poverty, 13. 2024-10-01 16:03:32.
The World Health Organization (WHO) has emphasized the urgent need for alternative strategies to chemical insecticides for controlling mosquito populations, particularly the invasive Aedes species, which are known vectors of arboviruses. Among these alternative approaches, the sterile insect technique (SIT) is experiencing rapid development, with numerous pilot trials being conducted worldwide. This review aims to elucidate the principles of SIT and highlight the significant recent advancements that have facilitated its scalability. I also employ a phased conditional approach to categorize the progression of 39 projects, drawing on peer reviewed studies, press releases and direct communication with project managers. This review indicates that a substantial number of projects illustrate the efficacy of SIT in suppressing Aedes populations, with one project even demonstrating a reduction in dengue incidence. I offer several recommendations to mitigate potential failures and address the challenges of compensation and overcompensation when implementing SIT field trials. Furthermore, I examine the potential implications of male mating harassment on the effectiveness of SIT in reducing disease transmission. This comprehensive assessment underscores the promise of SIT as a viable strategy for mosquito control. The insights gained from these trials not only contribute to the understanding of SIT’s effectiveness but also highlight the importance of careful project management and ecological considerations in the pursuit of public health objectives.
Mark–Release–Recapture Trial with Aedes albopictus (Diptera, Culicidae) Irradiated Males: Population Parameters and Climatic Factors
31590Amaro FIF, Soares P, Velo E, et al, Insects, 15. 2024-09-17 12:23:28.
Aedes albopictus mosquitoes spread arboviruses like dengue, Zika, or chikungunya. The Sterile Insect Technique (SIT) can be used as a prevention and control tool against Ae. albopictus populations. Mark–release–recapture (MRR) trials are fundamental to estimate the size of the wild population in target areas and to determine the dispersal capacity and survival of sterile males in open field conditions. Environmental conditions can affect the MRR trial’s results; thus, the influence of climatic factors on the first MRR trial with Ae. albopictus marked sterile males conducted in Portugal was analyzed. In October 2022, for three consecutive weeks at two different release points, 84,000 sterile males were released over 50 ha of the study area, in the municipality of Faro, Southern Portugal, and mosquitoes were recaptured by human landing collection (HLC) one, two, four, and six days after release. Distance travelled, daily survival, and life expectancy in the field were estimated for the released sterile males and the influence of climatic factors was analyzed. Despite no statistically significant association being found with humidity, temperature, and precipitation, it is crucial to plan MRRs, considering weather conditions for a more efficient application of the SIT in an integrated vector management program.
Effectiveness of Wolbachia-mediated sterility coupled with sterile insect technique to suppress adult Aedes aegypti populations in Singapore: a synthetic control study
31580Bansal, Somya, et al., The Lancet Planetary Health, 8:617-628. 2024-09-17 10:04:54.
In this synthetic control study, we conducted a large-scale, field trial of IIT-SIT targeting Aedes aegypti among high-rise public housing estates in Singapore, an equatorial city state. Routinely collected data from a large, nationwide surveillance system of 57 990 unique mosquito traps, combined with a high-dimensional set of anthropogenic and environmental confounders were collected to ascertain mosquito abundance and its key drivers. Four townships were selected as the intervention groups (approximate population size of 607 872 residents as of 2022), wherein interventions that combined ITT with SIT over the course of the study period were conducted. Townships were subject to releases of wAlbB-SG male A aegypti mosquitoes twice a week. Data were assessed over the course of epidemiological weeks (EWs), which provide the finest temporal resolution of recorded Wolbachia release schedule and mosquito abundance data. A novel synthetic control framework was then developed to account for the non-randomised and staggered adoption setting of the intervention across trial sectors to identify the direct suppressive effectiveness of IIT-SIT on female A aegypti populations, the spillover effects in non-release areas, and the effect of the intervention on other mosquito populations such as Aedes albopictus. Furthermore, we recalculated effectiveness in terms of calendar time, time since intervention, and over multiple sites to examine heterogeneities in IIT-SIT effectiveness. Between EW27 2018 and EW26 2022, Wolbachia releases were conducted across 117 sectors, of which 97 had sufficient trap data, which were collected between EW8 2019 and EW26 2022. We found that Wolbachia-based IIT-SIT reduced wild-type female A aegypti populations by a mean of 62·01% (95% CI 60·68 to 63·26) by 3 months, 78·40% (77·56 to 79·18) by 6 months, and 91·32% (90·95 to 91·66) by at least 18 months of releases. We also found a smaller but non-negligible spillover suppression effect that gradually increased over time (mean spillover intervention effectiveness 61·02% [95% CI 57·89 to 63·72] in adjacent, non-intervention sectors). Although no consistent change in A albopictus populations was seen across the four intervention townships after Wolbachia releases, the average intervention effectiveness on the A albopictus population across all release sectors was –25·80% (95% CI –30·93 to –21·05), which was driven by increases in two towns.
Optimizing and synchronizing Aedes aegypti colony for Sterile Insect Technique application: Egg hatching, larval development, and adult emergence rate
31193Jennifer Thieme Castellon, Solomon Kibret Birhanie, Ale Macias, Rubi Casas, Jacob Hans, Michelle Q. Brown, Acta Tropica, 259. 2024-08-27 08:24:10.
Mosquito Sterile Insect Technique (SIT) programs can be developed in smaller agencies through synchronization of the colony development to take advantage of the natural male early emergence. This paper examined key aspects of Ae. aegypti colony synchronization work, including egg hatching, larval development, and adult emergence to produce sufficient numbers of adult male mosquitoes within a specific timeframe for irradiation and release. Our data indicated that a relatively low percentage of males are required for colony propagation. Additional results highlighted that fresher Ae. aegypti eggs could yield as high as a 93 % hatching success than older eggs when placed under vacuum pressure in yeast infused water for 1.5 h. Eggs that were one-month old hatched (93 %) better than older eggs (0–32 %). A higher egg density in the hatching flask was correlated to a lower hatch rate, and higher larval density was related to unsynchronized pupae and delayed adult emergence. By keeping Ae. aegypti larvae at reasonable density, over 95 % of adults emerged on the first two days of emergence – indicating a high synchronicity. A standardized colony maintenance protocol therefore renders a synchronized larval development and adult male emergence which are critical in SIT programs.
Mark–Release–Recapture (MRR) of Sterile Male Aedes albopictus (Skuse) in Sri Lanka: Field Performance of Sterile Males and Estimation of the Wild Mosquito Population Density
30876Hapugoda, Menaka, Nilmini Silva Gunawardena, Tharaka Ranathunge, Jeremy Bouyer, Hamidou Maiga, Kankanige Karunathilake, Gayan Parakrama Withanage, Indika Weerasinghe, Bazoumana B. D. Sow, and Jeevanie Harishchandra, Insects, 15:466. 2024-07-02 13:27:59.
Dengue is an important mosquito-borne disease in Sri Lanka. The Sterile Insect Technique (SIT) is an environment-friendly and novel method that can suppress dengue vector mosquitoes in Sri Lanka. This study aimed to evaluate the field performance of sterile males and the density of wild male Aedes albopictus (Skuse) using a Mark–Release–Recapture (MRR) assay. Laboratory-colonized male pupae were exposed to 50 Gy gamma using a Co60 source. Sterile males (approx. 10,000) marked with fluorescent dust were released weekly for 4 consecutive weeks (January–February 2021) in a geographically isolated 30 ha site in Gampaha. Results show sterile males could disperse up to 543.8 m with a mean distance of 255.1 ± 44.6 m and survive up to 6 days with a mean life expectancy of 3.55 ± 2.32 days. A high field mating competitiveness of sterile males based on a Fried value of 0.47 ± 0.007 and significant induced sterility in the wild eggs in the second generation were found. The mean wild male mosquito population density was 163 males/ha. The data generated will be useful for designing future trials in Sri Lanka and other countries with similar situations.
Exploration of the potential of a boosted sterile insect technique to control fruit flies in mango orchards
30856Esther Gnilane Diouf, Thierry Brévault, Saliou Ndiaye, Cyril Piou, Pest Management Science, 2024-06-28 15:39:38.
An innovative version of the sterile insect technique (SIT) for pest control, called boosted SIT, relies on the use of sterile males coated with a biocide to control a target wild pest population of the same species. The objective of the present study was to assess the relevance of such technology to control the fruit fly Bactrocera dorsalis and fruit losses in mango orchards using. An agent-based simulation model named BOOSTIT was used to explore the reduction of fruit losses thank to sterile male fruit flies control and economic benefits according to different strategies of sterile male release. The simulation considered a landscape of 30.25 ha made up of four mango orchards. The SIT and the boosted SIT reduced fruit losses when releases were made before the mango fruiting period. According to model simulations, releases should be performed at least seven times at 2-week intervals and with a sterile/wild male ratio of at least 10:1. Considering the benefit/cost ratio (BCR), few releases should be done with a late start date. The BCR showed economic gains from the two control methods, the number of saved fruits and BCR being higher for SIT. Our simulations showed that SIT would have better results than the boosted SIT to contribute to an effective control of Bactrocera dorsalis at the scale of a small landscape. We highlight the need for laboratory studies of other types of pathogen to find a suitable one with higher incubation time and lower cost. © 2024 Society of Chemical Industry.
Eliminating malaria vectors with precision-guided sterile males
30852Reema A. Apte, Andrea L. Smidler, James J. Pai, et al, Applied Biological Sciences, 121. 2024-06-28 12:20:46.
Controlling the principal African malaria vector, the mosquito Anopheles gambiae, is considered essential to curtail malaria transmission. However, existing vector control technologies rely on insecticides, which are becoming increasingly ineffective. Sterile insect technique (SIT) is a powerful suppression approach that has successfully eradicated a number of insect pests, yet the A. gambiae toolkit lacks the requisite technologies for its implementation. SIT relies on iterative mass releases of nonbiting, nondriving, sterile males which seek out and mate with monandrous wild females. Once mated, females are permanently sterilized due to mating-induced refractoriness, which results in population suppression of the subsequent generation. However, sterilization by traditional methods renders males unfit, making the creation of precise genetic sterilization methods imperative. Here, we introduce a vector control technology termed precision-guided sterile insect technique (pgSIT), in A. gambiae for inducible, programmed male sterilization and female elimination for wide-scale use in SIT campaigns. Using a binary CRISPR strategy, we cross separate engineered Cas9 and gRNA strains to disrupt male-fertility and female-essential genes, yielding >99.5% male sterility and >99.9% female lethality in hybrid progeny. We demonstrate that these genetically sterilized males have good longevity, are able to induce sustained population suppression in cage trials, and are predicted to eliminate wild A. gambiae populations using mathematical models, making them ideal candidates for release. This work provides a valuable addition to the malaria genetic biocontrol toolkit, enabling scalable SIT-like confinable, species-specific, and safe suppression in the species.
Upscaling irradiation protocols of Aedes albopictus pupae within an SIT program in Reunion Island
30485Marquereau, L., Yamada, H., Damiens, D. et al., Scientific Reports, 14. 2024-06-04 16:44:56.
The implementation of the sterile insect technique against Aedes albopictus relies on many parameters, in particular on the success of the sterilization of males to be released into the target area in overflooding numbers to mate with wild females. Achieving consistent sterility levels requires efficient and standardized irradiation protocols. Here, we assessed the effects of exposure environment, density of pupae, irradiation dose, quantity of water and location in the canister on the induced sterility of male pupae. We found that the irradiation of 2000 pupae in 130 ml of water and with a dose of 40 Gy was the best combination of factors to reliably sterilize male pupae with the specific irradiator used in our control program, allowing the sterilization of 14000 pupae per exposure cycle. The location in the canister had no effect on induced sterility. The results reported here allowed the standardization and optimization of irradiation protocols for a Sterile Insect Technique program to control Ae. albopictus on Reunion Island, which required the production of more than 300,000 sterile males per week.
To fend off aggressive female mosquitoes, L.A. is releasing thousands of sterile males
29882Evan Bush, NBC News, 2024-05-07 15:46:02.
In Los Angeles, those who wage war on mosquitoes are adding a weapon to their arsenal: more mosquitoes. The Greater Los Angeles County Vector Control District on Thursday launched a pilot program to release tens of thousands of irradiated, lab-raised mosquitoes into the local environment. These mosquitoes are all male and have been sterilized by the radiation, so the hope is that they will find wild female mates and impregnate them with dead-end sperm, rendering the resulting eggs worthless. The target is a particular species, Aedes aegypti. The insects, which began to populate Los Angeles County in 2014, have evolved to hone in on one thing — you. “Thousands of years ago, a strain of Aedes aegypti moved in close to people and started to specialize to live near houses and bite people,” said Daniel Hahn, a professor in the University of Florida’s Department of Entomology and Nematology. “They’re characterized as aggressive nuisance biters because they’ll bite you all day long.” Aedes Aegypti thrive in backyards and make their homes in small containers like bottle caps and dog bowls. They can carry worrisome diseases like yellow fever, Chikungunya, Zika and dengue. “We know our residents are suffering,” said Susanne Kluh, the general manager of the Greater Los Angeles County Vector Control District, which serves 6 million people and has more than 90 full-time staffers. The district on Thursday released about 20,000 sterile male mosquitoes, dyed to appear fluorescent under a black light, as part of its final pilot program test. Male Aedes Aegypti mosquitoes don’t bite, so experts say the program poses near-zero risk to humans.
CRISPR could eradicate horrific parasite that’s killing cattle
28993Kristin Houser, Freethink, 2024-03-11 10:19:23.
Uruguay is developing a CRISPR gene drive to eradicate the New World screwworm, a parasitic fly that kills cattle in a painful, grisly fashion. Releasing it into the wild would have risks, but if it works, it could help rid South America of this horrific agricultural pest. The screwworm fly lays its eggs on living creatures — often livestock — and once they hatch, the larvae eat into the animal’s flesh for about a week, before emerging from the tunnel they created and flying away. “We know that it’s horrendously painful, because people get affected by this, and the standard of treatment is you give them morphine immediately so that surgeons can cut the things out — because it’s just that painful; it’s unbelievably agonizing,” Kevin Esvelt, a biologist at the MIT Media Lab, told the 80,000 Hours podcast in 2023. Aside from being painful, screwworm infestations of livestock are incredibly costly. In the 1950s, the US meat and dairy industries were losing an estimated $200 million per year to the pests — that’d be about $2.3 billion today. Screwworms are no longer a problem for American farmers thanks to the USDA. In 1955, it set out to eradicate the screwworm in the US by irradiating the insects’ larvae, which made adults sterile. Infertile males could then be released into infested areas to mate with females, which wouldn’t produce any offspring.
Protecting the peppers: Unlocking the potential of the sterile insect technique
28989Society of Chemical Industry, Phys.org, 2024-03-11 10:00:52.
For the first time, researchers in Canada have investigated the use of the sterile insect technique for controlling populations of the pepper weevil, Anthonomus eugenii, an economically significant crop pest in North America. The paper, published in Pest Management Science, revealed compelling findings on the use of gamma irradiation as a sterilization technique to improve the sustainability and effectiveness of pepper weevil management worldwide. The study was a collaboration between Bruce Power, Nordion Inc., the University of Guelph, Agriculture and Agri-Food Canada, and the Fruit and Vegetable Growers of Canada. A. eugenii poses a significant challenge to pepper growers across much of North America, causing millions of dollars worth of crop damage annually. The beetle larvae damage the flowers and immature fruit of capsicum plants, with infestations causing yield losses of up to 90%. Managing A. eugenii populations is particularly challenging as the development of beetle larvae takes place in the protective confines of pepper fruits. Roselyne Labbe, Greenhouse Entomologist at Agriculture and Agri-Food, Canada, and corresponding author of the study, explained the challenges in identifying effective strategies to manage populations of A. eugenii. "In prior research, we found that few conventional, reduced-risk, or microbial pesticides could effectively knock down adult populations of the pepper weevil on greenhouse pepper crops."
Mosquito Control releases over 100K sterile male mosquitos to combat Aedes aegypti population
28978NBC2 News, 2024-03-05 14:41:50.
Mosquito Control releases over 100K sterile male mosquitos to combat Aedes aegypti population
CRISPR-mediated germline mutagenesis for genetic sterilization of Anopheles gambiae males
28970Smidler, A.L., Marrogi, E., Kauffman, J. et al., Scientific Reports, 14. 2024-03-05 13:54:40.
Rapid spread of insecticide resistance among anopheline mosquitoes threatens malaria elimination efforts, necessitating development of alternative vector control technologies. Sterile insect technique (SIT) has been successfully implemented in multiple insect pests to suppress field populations by the release of large numbers of sterile males, yet it has proven difficult to adapt to Anopheles vectors. Here we outline adaptation of a CRISPR-based genetic sterilization system to selectively ablate male sperm cells in the malaria mosquito Anopheles gambiae. We achieve robust mosaic biallelic mutagenesis of zero population growth (zpg, a gene essential for differentiation of germ cells) in F1 individuals after intercrossing a germline-expressing Cas9 transgenic line to a line expressing zpg-targeting gRNAs. Approximately 95% of mutagenized males display complete genetic sterilization, and cause similarly high levels of infertility in their female mates. Using a fluorescence reporter that allows detection of the germline leads to a 100% accurate selection of spermless males, improving the system. These males cause a striking reduction in mosquito population size when released at field-like frequencies in competition cages against wild type males. These findings demonstrate that such a genetic system could be adopted for SIT against important malaria vectors.
Revolutionizing Livestock Biosecurity: Using CRISPR Technology to Combat the New World Screwworm
28963Dr. Jessica Nelson, Medriva, 2024-03-05 13:07:55.
The New World screwworm, a persistent parasite responsible for significant damage to the global livestock industry, may soon meet its match. Researchers at Uruguay's National Institute of Agricultural Research (INIA) have developed a gene drive using CRISPR technology to combat this destructive pest. By manipulating the reproductive process of the screwworm fly, INIA scientists aim to cause a population crash, thereby reducing the parasite's devastating impact on the livestock industry. CRISPR gene drive technology offers a potentially more efficient and powerful solution compared to previous methods, such as the sterile insect technique (SIT) used by the US. Unlike traditional techniques, CRISPR gene drives aim to spread fertility-damaging genes throughout the screwworm population, causing a significant decrease in their numbers. The process works by making female screwworms sterile. The ultimate goal is to release gene-edited male screwworm flies into the wild. These males will mate with females, passing on the gene drive and leading to a population crash of the screwworm fly. This innovative approach has shown promise in caged trials and is currently being tested further in the INIA labs.
Uruguay wants to use gene drives to eradicate devastating screwworms
28961Abdullahi Tsanni, MIT Technology Review, 2024-03-05 12:53:17.
On a warm, sunny day in Montevideo, Uruguay, the air is smogless and crisp. Inside a highly secured facility at the National Institute of Agricultural Research (INIA) are a sophisticated gene gun, giant microscopes, and tens of thousands of gene-edited flies, their bright blue wings fluttering against the walls of their small, white, netted cages. These flies—shown to me on video by an INIA veterinarian, Alejo Menchaca—are a new weapon that may soon be unleashed against an enemy that kills cattle and costs the livestock industry millions of dollars every year: the New World screwworm, a parasite common in parts of South America and the Caribbean. When a female screwworm fly attacks cattle, it lays eggs, which hatch and turn into worm-like larvae that screw down into the host animal, feeding on flesh along their way and damaging the animal’s skin. Left untreated, the animals eventually die in excruciating agony. But Menchaca and colleagues have a plan. Using the genome-editing system CRISPR, they’ve developed what’s known as a gene drive, a type of genetic element that manipulates the reproductive process to spread farther and faster than an ordinary gene. They are about to move into the next stage of caged trials in the lab, with a view to eventually using the genetic tool to decimate the screwworm fly population. In collaboration with Institut Pasteur de Montevideo, they have received a $450,000 grant from the Inter-American Development Bank (IDB) for the research.
Taking the fight against disease to mosquitoes
28948Gregory Devine, Setopati, 2024-02-27 18:33:30.
In the medium term it's likely that suppression strategies involving self-limiting genetic modifications, Wolbachia infection and irradiation will be extended to a small number of our most important mosquito vectors of disease.
Biotech Mosquitoes Can Help to Regain Ground in Fight Against Malaria
28932Florence Banoba, East News, 2024-02-27 17:59:07.
In response to the recent opinion articles that ran in the National print and online media in the last couple of days (1st and 5th February, 2024), regarding the use of GMO technology as a tool in the fight against malaria, I wish to address the writer’s broad-brush dismissal of the significance of genetic modification technologies in combating malaria. It is crucial, from the outset, to clarify a fundamental distinction overlooked in the article between Gene-drive and Self-limiting technologies in addressing this global health challenge. As rightly stated in that article, gene-drive technology refers to a genetic engineering technique that aims to spread a particular gene throughout a population at an accelerated rate. The primary objective would be to either suppress a mosquito population or reduce its ability to transmit malaria. Under this method, the introduced mosquitoes are designed to stay in the environment for long. In contrast, self-limiting technology involves the introduction of genetically modified organisms which possess traits designed to limit their population growth. This technology focuses on controlling or suppressing the modified organisms themselves.
Maui ‘ground zero’ for release of billions of biopesticide lab-altered mosquitoes
28929Michael Nevradakis, LifeSite, 2024-02-27 16:57:41.
Up to 775,992,000 bacteria-infected mosquitoes could be released in Maui every week for the next 20 years, according to Hawaii Unites, an environmental advocacy group that last month lost its bid to require the state to conduct an environmental impact statement before allowing the controversial project to proceed. Hawaii Unites in May 2023 sued the state in the Circuit Court of the First Circuit in Hawaii. The group’s president and founder, Tina Lia, told The Defender: "These biopesticide lab-altered mosquitoes are already being released in East Maui. Hawaii Unites has taken the state to court seeking a ruling to require an environmental impact statement for the project and comprehensive studies of the risks". She said Hawaii Unites describes itself as “a 501(c)(3) non-profit organization dedicated to the conservation and protection of our environment and natural resources,” with a focus on “protecting the health of Hawai‘i’s people, wildlife, and the ‘āina from the State of Hawaii’s biopesticide bacteria-infected mosquito experiment.”
Judge sides with Hawaii to block challenge to mosquito release plan
28925Candice Cheung, Courthouse News Service, 2024-02-27 16:29:17.
A planned program to save endemic Hawaiian birds from avian malaria by releasing thousands of biopesticide mosquitoes into Maui’s rainforest will go on, despite an attempt by an environmental nonprofit to block the project.First Circuit Court Judge John Tonaki ruled Tuesday in favor of the state of Hawaii, its Department of Land and Natural Resources and conservationists to block a lawsuit claiming the state agency did not complete a proper environmental evaluation of program aimed at curbing mosquito population to prevent them from spreading avian malaria.“This is a victory for our endangered forest birds who some native Hawaiians consider their ancestors,” Dawn Chang, chair of the state’s Board of Land and Natural Resources said in a statement. “The HEPA is an important tool that enables decisionmakers to assess environmental impacts — not the sword by which misinformation kills a project, aimed at saving native species.”
Deep orange gene editing triggers temperature-sensitive lethal phenotypes in Ceratitis capitata
28906Sollazzo, G., Nikolouli, K., Gouvi, G. et al., BMC Biotechnology, 24. 2024-02-20 15:24:38.
The Mediterranean fruit fly, Ceratitis capitata, is a significant agricultural pest managed through area-wide integrated pest management (AW-IPM) including a sterile insect technique (SIT) component. Male-only releases increase the efficiency and cost-effectiveness of SIT programs, which can be achieved through the development of genetic sexing strains (GSS). The most successful GSS developed to date is the C. capitata VIENNA 8 GSS, constructed using classical genetic approaches and an irradiation-induced translocation with two selectable markers: the white pupae (wp) and temperature-sensitive lethal (tsl) genes. However, currently used methods for selecting suitable markers and inducing translocations are stochastic and non-specific, resulting in a laborious and time-consuming process. Recent efforts have focused on identifying the gene(s) and the causal mutation(s) for suitable phenotypes, such as wp and tsl, which could be used as selectable markers for developing a generic approach for constructing GSS. The wp gene was recently identified, and efforts have been initiated to identify the tsl gene. This study investigates Ceratitis capitata deep orange (Ccdor) as a tsl candidate gene and its potential to induce tsl phenotypes. An integrated approach based on cytogenetics, genomics, bioinformatics, and gene editing was used to characterize the Ccdor. Its location was confirmed on the right arm of chromosome 5 in the putative tsl genomic region. Knock-out of Ccdor using CRISPR/Cas9-NHEJ and targeting the fourth exon resulted in lethality at mid- and late-pupal stage, while the successful application of CRISPR HDR introducing a point mutation on the sixth exon resulted in the establishment of the desired strain and two additional strains (dor 12del and dor 51dup), all of them expressing tsl phenotypes and presenting no (or minimal) fitness cost when reared at 25 °C. One of the strains exhibited complete lethality when embryos were exposed at 36 °C. Gene editing of the deep orange gene in Ceratitis capitata resulted in the establishment of temperature-sensitive lethal mutant strains. The induced mutations did not significantly affect the rearing efficiency of the strains. As deep orange is a highly conserved gene, these data suggest that it can be considered a target for the development of tsl mutations which could potentially be used to develop novel genetic sexing strains in insect pests and disease vectors.
Mass-Rearing Conditions Do Not Always Reduce Genetic Diversity: The Case of the Mexican Fruit Fly, Anastrepha ludens (Diptera: Tephritidae)
28817Ruiz-Montoya L, Sánchez-Rosario M, López-Gómez E, Garcia-Bautista M, Canedo-Texón A, Haymer D, Liedo P, Insects, 15:56. 2024-01-23 14:31:12.
The application of the sterile insect technique (SIT) requires the adaptation of insects to mass-rearing conditions. It is generally accepted that this adaptation may include a reduction in genetic diversity and an associated loss of desirable characteristics for the effective performance of sterile insects in the field. Here, we compare the genetic diversity of two mass-reared strains of the Mexican fruit fly, Anastrepha ludens, and a wild (WIL) population collected near Tapachula, Mexico, using seven DNA microsatellites as molecular genetic markers. The mass-reared strains were a bisexual laboratory strain (LAB) with approximately 130 generations under mass-rearing and a genetic sexing strain, Tapachula-7 (TA7), also under mass-rearing for 100 generations. Our results revealed an overall low level of genetic differentiation (approximately 15%) among the three strains, with the LAB and WIL populations being genetically most similar and TA7 most genetically differentiated. Although there were some differences in allele frequencies between strains, our results show that overall, the adaptation to mass-rearing conditions did not reduce genetic variability compared to the wild sample in terms of heterozygosity or allelic richness, nor did it appear to alter the level of inbreeding with respect to the wild populations. These results are contrary to the general idea that mass-rearing always results in a reduction in genetic diversity. Overall, our findings can contribute to a better understanding of the impact that adaptation to mass-rearing conditions may have on the genetic make-up of strains.
Mosquito makeover: Tahiti’s groundbreaking solution to disease
28823Atutahi Potaka-Dewes, Pacific Media Network, 2024-01-19 14:49:43.
Mosquitoes are responsible for transmitting such diseases as dengue, malaria, zika, chikungunya, or filariosis, causing millions of deaths worldwide. French Polynesia is taking a groundbreaking initiative to address public health concerns and demonstrate a commitment to finding environmentally friendly solutions to curb disease spread. Building on a successful decade-long pilot project on the atoll Teti’aroa, the innovative method involves the strategic release of sterilised male Aedes Aegypti mosquitoes. The process sees the release of sterile males that will "contaminate" females, rendering them sterile and thereby naturally reducing the proliferation of the disease-bearing insect population. The Louis Malardé Institute's entomology laboratory says they have now developed an X-ray device that can mass-sterilise the males.
Sex or poison? Genetic pest management in the 21st century
28782Luke Alphey, BMC Biology, 21:289. 2024-01-11 13:14:20.
Pests do enormous damage to human and animal health, to agriculture and to biodiversity, with mosquitoes transmitting pathogens, insect larvae eating crops or invasive rodents threatening the last island refuges of endangered birds. This commentary focuses on insects, particularly mosquitoes. However, most considerations apply equally to other pest species. Genetic pest management (GPM) is the use of genetics to control pests through mating of modified pests with their wildtype counterparts. This allows heritable traits to be transferred (“introgressed”) into the wild pest population. In principle, any sexually reproducing pest species can be targeted. The aim is to reduce harm done by the pest population, with typical intended outcomes overwhelmingly falling into two types: population suppression and population modification. For population suppression, one would introgress fitness-reducing traits, such as lethality or sterility, leading to reduction in the numerical size of the pest populations if spread into the target population at sufficiently high frequency. Population modification aims to reduce the harm done by the pest without large changes in the numerical size of the pest population, for example by reducing the ability to transmit disease (“vector competence”) of modified mosquitoes. If such traits, or the DNA sequences encoding them, can be sustained at sufficiently high allele frequency in the target population then the desired harm-reduction outcome should be achieved, by reduction in the number of pests or by reduction in the per-pest harm.
Assessing the sterility and quality of gamma-irradiated pepper weevils, Anthonomus eugenii (Coleoptera: Curculionidae), toward the development of the sterile insect technique
28713Basso, J.V., Labbe, R. and Scott-Dupree, C., Pest Management Science, 2023-12-18 09:48:19.
The pepper weevil (PW), Anthonomus eugenii, is an economically significant pest of cultivated Capsicum spp. pepper crops in North America where it remains a challenge to manage because of its cryptic immature life stages. The sterile insect technique (SIT) is a genetic pest management tactic that relies on the release of insects that have been sterilized with ionizing radiation to lower the population reproductive rate. Toward developing an effective PW-SIT program, this study has, for the first time, investigated the effects of gamma irradiation on the sterility and survival of this species. Among the array of doses tested, we found that pupal PW males and females irradiated at 110 Gy produced no adult offspring. Furthermore, females mated with a male irradiated at 110 Gy had high egg sterility (97.3%), and irradiated females nearly completely failed to lay eggs (97.5%). Individuals irradiated at this dose had a shortened lifespan (lethal time to 50% mortality values of 12 and 11 days for males and females, respectively) and quantitatively reduced spontaneous flight activity. The eclosion rate of PW pupae was not significantly reduced by any radiation treatment. This study suggests that PWs irradiated at a gamma radiation dose of 110 Gy as pupae could feasibly be used in a PW-SIT program, because both males and females were 100% sterile at this dose. These findings will inform the development of a SIT program that could considerably improve the sustainability and effectiveness of PW management in greenhouse and field pepper crops worldwide.
Side effects of X-ray irradiation on flight ability of Cydia pomonella moth
28694Huang, S.-W., Zhang, J.-H., Wei, Z.-H., Yang, X.-M., Wang, X.-Y. and Yang, X.-Q., Pest Management Science, 2023-12-12 14:27:29.
The sterile insect technique (SIT) has proven to be an effective approach in managing the population of major invasive pests Our previous studies showed that irradiation of males at a dosage of 366 Gy X-rays resulted in complete sterility. However, the mating competitiveness of sterilized males is significantly compromised, which can be attributed to a decline in their ability to fly. In this study, we examined the flight patterns of both male and female adults of C. pomonella. The results revealed significant variations in the average flight speed of both genders at different stages of maturity, with females displaying longer flight duration and covering greater distances. Effect of irradiation on the flight performance of 3-day-old male moths was further evaluated, as they demonstrated the longest flight distance. The findings indicated a significant decrease in flight distance, duration, and average speed, due to wing deformities caused by irradiation, which also limited the dispersal distance of moths in orchards, as indicated by the mark-and-recapture assay. Quantitative reverse-transcription PCR analysis revealed a down-regulation of flight-related genes such as flightin, myosin heavy chain, and distal-less following radiation exposure. These findings demonstrate that X-ray irradiation at a radiation dose of 366 Gy has a detrimental effect on the flight ability of male C. pomonella adults. These insights not only contribute to a better understanding of how radiation sterilization diminishes the mating competitiveness of male moths, but also aid in the development and improvement of SIT practices for the effectively controlling C. pomonella.
Aerial release of Aedes aegypti male mosquitoes using an unmanned aerial vehicle: a novel control strategy
28690Valdez-Delgado KM, Ríos-Delgado JC, Nettel-Cruz JA, Angulo-Kladt R, Villarreal-Treviño C., Salud Pública de México, 65. 2023-12-12 14:17:22.
Objective. To development of a methodology for the chilling, handling, transport, and release of male Aedes aegypti mosquitoes, reared in insectary conditions to release in the field with unmanned vehicles to compete sexually with wild males in the field. Materials and methods. A population of Ae. aegypti from different areas in Tapachula, Chiapas, was used. Laboratory tests were conducted: Effect of temperature and cooling time on the knockdown, recovery of males, and copulatory success. Results. The chilling temperature of 3 ± 1ºC for 30 min, was used as a knockdown temperature before handling, packing, transportation, and aerial release. The males subjected to the entire process, including the semi-field aerial release test, showed normal sexual behavior activity, obtaining 100% of females inseminated. Conclusion. These results present the feasibility of applying a new control methodology using unmanned aerial vehicle (UAV) as support for the sterile insect release technique (SIT), use of Wolbachia or both, in male Ae. aegypti, for the design of strategies to control their populations.
The Sterile Insect Technique can efficiently reduce the reproduction of the spotted wing drosophila (Drosophila suzukii) in strawberry
28688B. Gard, A. Panel, A. Labbetoul, N. Bosshard, A. Xuereb, B. Cariou, A. Debelle, C. Oliva, S. Fellous, bioRxiv, 2023-12-11 13:19:11.
The spotted wing drosophila (SWD) Drosophila suzukii (Diptera: Drosophilidae) is a highly problematic pest in soft fruit crops. Since its introduction in Europe in 2008, no satisfying nor environment-friendly control method has emerged against this species. The sterile insect technique (SIT) has proven efficient at controlling numerous fruit fly species. In recent years, key elements of SIT against D. suzukii have become available, leading to the publication of encouraging results. However, field- and field-like experiments are notoriously under the influence of various, often unidentified factors granting the need for replicated studies. In this experiment, we assayed the efficacy of a high-performance strain at reducing the reproduction of D. suzukii in complex, yet replicated and controlled conditions. Two ratios of sterile to fertile insects (5:1 and 1:1) using bisexual releases were compared to a control treatment with fertile, wild flies only. The presence of sterile individuals at a 5:1 ratio significantly reduced fly reproduction, measured after 5 days, by an approximate threefold factor. However, the proportion of infested fruits in the treated plots remained unaffected. The number of available berries in the cage appeared as an unexpected determinant of fly infestation, suggesting undocumented density-dependent processes. The success of this assay opens the door to larger scales experiments, over several generations, and, in the near future, the field-evaluation of the efficacy of the SIT to control D. suzukii.
Population suppression with dominant female-lethal alleles is boosted by homing gene drive
28685Jinyu Zhu, Jingheng Chen, Yiran Liu, Xuejiao Xu, Jackson Champer, bioRxiv, 2023-12-07 10:24:25.
Methods to suppress pest insect populations using genetic constructs and repeated releases of male homozygotes have recently been shown to be an attractive alternative to older sterile insect technique based on radiation. Female-specific lethal alleles have substantially increased power, but still require large, sustained transgenic insect releases. Gene drive alleles bias their own inheritance to spread throughout populations, potentially allowing population suppression with a single, small-size release. However, suppression drives often suffer from efficiency issues, and the most well-studied type, homing drives, tend to spread without limit. In this study, we show that coupling female-specific lethal alleles with homing gene drive allowed substantial improvement in efficiency while still retaining the self-limiting nature (and thus confinement) of a lethal allele strategy. Using a mosquito model, we show the required releases sizes for population elimination in a variety of scenarios, including different density growth curves, with comparisons to other systems. Resistance alleles reduced the power of this method, but these could be overcome by targeting an essential gene with the drive while also providing rescue. A proof-of-principle demonstration of this system in Drosophila melanogaster was effective in both basing its inheritance and achieving high lethality among females that inherit the construct in the absence of antibiotic. Overall, our study shows that substantial improvements can be achieved in female-specific lethal systems for population suppression by combining them with a gene drive.
Different mechanisms of X-ray irradiation-induced male and female sterility in Aedes aegypti
28570Zhang, H., Trueman, E., Hou, X. et al., BMC Biology, 21. 2023-11-29 14:14:21.
Aedes aegypti (Ae. aegypti) is the major vector that transmits many diseases including dengue, Zika, and filariasis in tropical and subtropical regions. Due to the growing resistance to chemical-based insecticides, biological control methods have become an emerging direction to control mosquito populations. The sterile insect technique (SIT) deploys high doses of ionizing radiation to sterilize male mosquitoes before the release. The Wolbachia-based population suppression method of the incompatible insect technique (IIT) involves the release of Wolbachia-infected males to sterilize uninfected field females. Due to the lack of perfect sex separation tools, a low percentage of female contamination is detected in the male population. To prevent the unintentional release of these Wolbachia-infected females which might result in population replacement, a low dose of X-ray irradiation is deployed to sterilize any female escapees. However, it remains unclear whether these irradiation-induced male and female sterilizations share common mechanisms.
Effects of different diets on Aedes aegypti adults: improving rearing techniques for sterile insect technique
28541Aynoanne Leandro Barbosa , Glayciane Costa Gois , Verenna Barros dos Santos , Aline Taiane de Macedo Pinto , Bianca Pires de Castro Andrade , Lucas Barbosa de Souza , Fernanda Hohana Almeida e Sá , Jair Fernandes Virginio and Mário Adriano Ávila Queiroz, Bulletin of Entomological Research, 2023-11-28 11:17:21.
The aim was to evaluate the effect of different energy diets available in adulthood on the longevity, dispersal capacity and sexual performance of Aedes aegypti produced under a mass-rearing system. To evaluate the effects of diets in relation to the survival of the adult male insects of Ae. aegypti, six treatments were used: sucrose at a concentration of 10%, as a positive control (sack10); starvation, as a negative control (starvation); sucrose at a concentration of 20% associated with 1 g/l of ascorbic acid (sac20vitC); wild honey in a concentration of 10% (honey10); demerara sugar in a 10% concentration (demerara10); and sucrose at a concentration of 20% associated with 1 g/l of ascorbic acid and 0.5 g/l of amino acid proline (sac20vitCPr). Each treatment had 16 cages containing 50 adult males. For the tests of flight ability and propensity to copulation, five treatments were used (saca10; sac20vitC; mel10; demerara10; and sac20vitCPr), with males each for flight ability and females copulated by a single male for copulation propensity. The diet composed of sucrose at a concentration of 20% associated with ascorbic acid, as an antioxidant, improved the survival, flight ability and propensity to copulate in Ae. aegypti males under mass-rearing conditions, and may be useful to enhance the performance of sterile males, thus improving the success of sterile insect technique programmes.
Oxitec concludes GMO mosquito release phase
28361Anonymous, keysnews.com, 2023-11-08 09:35:19.
Oxitec and the Florida Keys Mosquito Control District announced last week that the release phase during the third season of the FKMCD-Oxitec Mosquito Project has concluded for the 2023 season. Mosquito population monitoring will continue for the next several weeks.9
Current Status of the Main Olive Pests: Useful Integrated Pest Management Strategies and Genetic Tools
28380E. Lantero, B. Matallanas and C. Callejas, Applied Sciences, 13. 2023-11-06 09:55:38.
Mediterranean olive cultivation faces challenges in the global environmental change context. Pests and diseases caused by arthropods such as Bactrocera oleae, Prays oleae, and certain vectors of Xylella fastidiosa are expected to increase and spread in part due to this global scenario. The control of these arthropods has relied on synthetic pesticides, the misuse of which has led to pest population resistance and concerns about their negative impacts on biodiversity and global health. Integrated pest management (IPM) methods have emerged through the careful consideration of all available control techniques and the subsequent integration of appropriate measures that discourage the development of pest populations. This paper reviews the IPM guidelines for olive cultivation, prioritizing the use of biological control methods, and the integration of genetics and biotechnology, which bring precision, efficacy, and safety. It evidences the importance of genetic analysis in pest populations, pesticide resistance and in the contributions of predators to pest control. Advances in formulations and delivery systems for pesticides such as Bacillus thuringiensis, plant-incorporated protectants, improved SIT techniques, and the specific efficacy of biologicals pesticides are covered. Finally, this paper explores promising tools such as RNAi and gene drive while recognizing the ethical, environmental, and regulatory challenges associated with their use. Shortly, these innovations have the potential to reduce the environmental impacts of pests while ensuring the long-term viability of the olive industry.
How to fight insects that transmit diseases to people without harming those who cannot?
28157Nation World News Desk, Nation World, 2023-10-20 11:55:16.
One way to avoid this severe environmental impact is to specifically control the population of species that cause problems. This can be done chemically by releasing hormones into the environment that prevent passage to the adult stage, or pheromones that make them believe that a beautiful insect is waiting for them ready for sex, when in fact they fell in the trap of death. The problem with these methods is that sometimes the required molecules are very expensive and not always specific to what we want. A more effective strategy is to sterilize the population of male insects with radioactivity. In nature, these males mate with females, but cannot produce children. This technique has been used for a long time with reasonable results, although it is not 100% effective and the use of radioactivity means the appearance of mutations and it may happen (unlikely) that some give some development for the insect, and a recurring problem for us.However, genetic engineering offers us help. CRISPR/Cas9 is a technology that allows us to make specific changes in a specific area of the genome of any living organism. We can give it a twist and, instead of applying this technique to the genome of an insect by making a specific modification, what we do is modify an insect so that its genome has everything it needs to activate CRISPR/Cas9. time and cause sterility. It’s like hiding in your genome a complete CRISPR/Cas9 kit and the instructions to change a specific gene to create sterility. What is the advantage? If we only disperse the sterile males, those that are not sterile (sterilization is never 100% and we have to compete with the native population) will continue to reproduce, and in a few generations the effect will disappear.
X-rays are as effective as gamma-rays for the sterilization of Glossina palpalis gambiensis Vanderplank, 1911 (Diptera: Glossinidae) for use in the sterile insect technique
28223B. A. Kaboré, A. Nawaj, H. Maiga, O. Soukia, S. Pagabeleguem, M. S. G. Ouédraogo/Sanon, M. J. B. Vreysen, R. L. Mach and C. J. de Beer, Scientific Reports, 13:17633. 2023-10-17 15:00:27.
An area-wide integrated pest management strategy with a sterile insect technique (SIT) component requires a radiation source for the sterilisation of male insects. Self-contained gamma irradiators, which were exclusively used in past SIT programmes, are now facing increasing constraints and challenges due to stringent regulations. As a potential alternative, new generation high output X-ray irradiators have been proposed. The feasibility of using X-ray irradiators was assessed by comparing the effects of both gamma- and X-ray irradiators on biological parameters of Glossina palpalis gambiensis (Vanderplank, 1911), that are important for SIT applications. The gamma irradiator Foss Model 812 and two X-ray irradiators, the Rad Source 2400 and the blood irradiator Raycell Mk2 were used. Glossina palpalis gambiensis males were exposed to radiation as pupae. A radiation dose of 110 Gy or above induced more than 97% sterility in females that mated with the irradiated males for all the irradiators. Adult emergence rate, flight propensity, survival and mating performance did not differ between gamma- and X-rays irradiators. These results suggest that irradiating pupae with a dose of 110 Gy is optimal for both gamma-and X-ray irradiators used in this study, to achieve a sterility of approximately 99%. Similar research on other tsetse species could gradually phase out the use of gamma-ray irradiators in favour of X-rays irradiators, especially for smaller SIT programmes.
Mosquito Embryo Microinjection
27969R. A. Harrell, Cold Spring Harbor Protocols, 2023-10-03 07:27:01.
Genetically modified (GM) mosquitoes are an important tool in the fight against mosquito-borne disease, both indirectly through their use in research investigating host–pathogen interaction, mosquito olfaction, and anthropomorphic behavior and in future direct uses for suppression and possibly eradication through sterile insect technique (SIT) and/or gene-drive programs. Successful creation of GM mosquitoes depends on microinjection procedures that precisely deliver injection materials while causing as little damage to mosquito embryos as possible. Genetic modification reagents, such as transposon system components (vector plasmids, helper plasmids, and helper mRNA), and CRISPR–Cas9 components (guide RNAs, Cas9 protein, plasmids expressing Cas9 and/or guide RNAs, and donor plasmids used in homology-directed repair [HDR]), must be delivered into the preblastoderm embryo at the posterior end where the pole cells will form before cellularization occurs. Sharp needles that pierce the embryo easily are important tools in this procedure and work best when the embryos are not desiccated. The two main procedures for mosquito embryo microinjection involve injecting embryos under halocarbon oil or under aqueous solution.
Next-generation genetic sexing strain establishment in the agricultural pest Ceratitis capitata
27972S. Davydova, J. Liu, N. Kandul, P., W. E. Braswell, O. Akbari, S. and A. Meccariello, bioRxiv, 2023.09.29.560088. 2023-10-01 07:32:11.
Tephritid fruit fly pests pose an increasing threat to the agricultural industry due to their global dispersion and a highly invasive nature. Here we showcase the feasibility of an early-detection SEPARATOR sex sorting approach through using the non-model Tephritid pest, Ceratitis capitata. This system relies on female-only fluorescent marker expression, accomplished through the use of a sex-specific intron of the highly-conserved transformer gene from C. capitata and Anastrepha ludens. The herein characterized strains have 100% desired phenotype outcomes, allowing accurate male-female separation during early development. Overall, we describe an antibiotic and temperature-independent sex-sorting system in C. capitata, which, moving forward, may be implemented in other non-model Tephritid pest species. This strategy can facilitate the establishment of genetic sexing systems with endogenous elements exclusively, which, on a wider scale, can improve pest population control strategies like sterile insect technique.Competing Interest StatementO.S.A is a founder of Agragene, Inc. and Synvect, Inc. with equity interest. N.P.K is a founder of Synvect, Inc. with equity interest. The terms of this arrangement have been reviewed and approved by the University of California, San Diego in accordance with its conflict-of-interest policies. All other authors declare no competing interests
Effect of 2 sex-sorting time schedules on SIT facility management
28345M. Malfacini, A. Puggioli, F. Balestrino, M. Carrieri, M. L. Dindo and R. Bellini, Journal of Insect Science, 23:9. 2023-09-18 10:58:06.
Improvements are needed in mosquito mass-rearing to effectively implement the sterile insect technique (SIT). However, managing this technique is challenging and resource intensive. SIT relies on mass rearing, sterilization, and release of adult males to reduce field populations. Maintaining an acceptable level of female presence, who can transmit viruses through biting, is crucial. Females are also essential for facility sustainability. Sex sorting plays a vital role in the production process, and our current mechanical sorting approach aims to obtain a high number of adult males with minimal female contamination within 24 h of pupation. Utilizing protandry helps control female contamination. While the 24-h sorting period achieves desired contamination levels, it may not yield enough females to sustain breeding lines, leading to increased labor costs that impact project sustainability. By delaying the sorting procedure to 48 h, we obtained sufficient females to sustain breeding lines, achieving a balance between male production and female contamination using the automatic version of the Fay–Morlan device as the sorting tool.
Development and characterization of microsatellite markers for the tsetse species Glossina brevipalpis and preliminary population genetics analyses
27882F. Gstöttenmayer, P. Moyaba, M. Rodriguez, F. C. Mulandane, H. N. Mucache, L. Neves, C. De Beer, S. Ravel, T. De Meeûs, R. L. Mach, M. J. B. Vreysen and A. M. M. Abd-Alla, Parasite, 30:34. 2023-09-15 08:27:06.
Tsetse flies, the vectors of African trypanosomes are of key medical and economic importance and one of the constraints for the development of Africa. Tsetse fly control is one of the most effective and sustainable strategies used for controlling the disease. Knowledge about population structure and level of gene flow between neighbouring populations of the target vector is of high importance to develop appropriate strategies for implementing effective management programmes. Microsatellites are commonly used to identify population structure and assess dispersal of the target populations and have been developed for several tsetse species but were lacking for Glossina brevipalpis. In this study, we screened the genome of G. brevipalpis to search for suitable microsatellite markers and nine were found to be efficient enough to distinguish between different tsetse populations. The availability of these novel microsatellite loci will help to better understand the population biology of G. brevipalpis and to assess the level of gene flow between different populations. Such information will help with the development of appropriate strategies to implement the sterile insect technique (SIT) in the framework of an area-wide integrated pest management (AW-IPM) approach to manage tsetse populations and ultimately address the trypanosomoses problem in these targeted areas.
Influence of environmental conditions on mass rearing parameters of tsetse flies at the Bobo-Dioulasso insectary (Burkina Faso): retrospective study
27966K. S. M. Dera, B. A. Kaboré, S. Pagabeleguem, A. A. Ouedraogo, A. I. Toé, M. Ira, A. M. G. Belem and G. M. S. O. Sanou, International Journal of Biological and Chemical Sciences, 17:1020-1032. 2023-08-24 07:18:58.
With the goal of eradicating tsetse flies and trypanosomiasis in Africa, several control methods have been developed. One of this is the biological control through the application of the sterile insect technique (SIT) as a part of an area-wide integrated pest management. This method required the mass production of sterile males with a high competitiveness. The success of the tsetse mass rearing is strongly linked to the rearing conditions. The objective of this study was to do a retrospective evaluation of the impact of ambient conditions on the production performances of Glossina palpalis gambiensis at Insectary of Bobo Dioulasso. Data of productivity, fecundity, adult emergence and environmental conditions (temperature and relative humidity) of the rearing rooms were recorded from March to June 2020 and were analysed. The results showed a reduction of the normal pupae produced and the increase of soft pupae during this period. In addition, the relative humidity has shown a significant positive correlation with the production of soft pupae, whereas it had a significant negative correlation with the number of pupae produced per female per 10 days. However, the temperature variation during the period of the data recording didn’t have any impact on the production parameters. Rearing rooms need a better management to avoid large variations in environmental parameters. © 2023 International Formulae Group. All rights reserved.
Effect of the Sterile Insect Technique and Augmentative Parasitoid Releases in a Fruit Fly Suppression Program in Mango-Producing Areas of Southeast Mexico
27989J. Cancino, P. Montoya, F. O. Gálvez, C. Gálvez and P. Liedo, Insects, 14. 2023-08-22 08:09:28.
The Sterile Insect Technique (SIT), by means of sterile male releases of Anastrepha ludens (Loew), coupled with Augmentative Biological Control (ABC), by releasing the parasitoid Diachasmimorpha longicaudata (Ashmead), was evaluated in a commercial mango production area for one year. The obtained results were compared with mean fruit fly population values from two previous years without the combined use of both techniques. The treatments were: SIT + ABC, SIT, ABC, and Control, and each treatment was established in blocks of 5000 Ha separated by distances of 5–10 km. The evaluations were carried out through fruit sampling to assess percent parasitism and trapping of adult flies to obtain Flies per Trap per Day (FTD) values. The mean percentage of parasitism increased from 0.59% in the control treatment to 19.38% in the block with ABC. The FTD values decreased from ~0.129 and ~0.012 in the control block to 0.0021 in the block with SIT and ABC, representing a 98% suppression. The difference between the two periods in the control block was not significant. We conclude that the integration of both techniques resulted in an additive suppression of the pest population, supporting the use of both control techniques in an area-wide pest management context.
Genetically modified Brit mosquitoes could stamp out malaria with Bill Gates’ backing
27619K. Williams, Mirror, 2023-08-15 09:49:13.
British super mosquitoes could be deployed worldwide to eradicate malaria. Billionaire Bill Gates is backing the British effort to send the country’s mosquitoes across the world in an effort to stamp out the deadly disease. This would work because the super mozzies, created by UK biotech firm Oxitec, are capable of killing off their disease-ridden rivals that spread the illness responsible for over half a million deaths a year.Oxitec genetically modifies insects to use them as biological insecticides. They work by the British mozzies being entirely male only and they carry a special gene that stops female offspring from surviving into adulthood. This is key because only the females bite and spread malaria. So Oxitec’s all-male mosquitoes are released into the wild and mate with the wild females, whose female offspring all die off. However, the male offspring survive and, unable to bite and spread the disease, go off into the world and mate with other wild females.
EPA Authorized Release Of 2 Billion More GMO Mosquitos
27606T. Mateescu, Health Thoroughfare, 2023-08-09 07:34:11.
A biotechnology company called Oxitec has produced genetically modified mosquitoes named GE mosquitoes. These mosquitoes are being released in the U.S. for a real-world experiment. Oxitec is using Aedes aegypti (A. aegypti) mosquitoes for this experiment. This species is known to carry diseases like yellow fever, dengue fever, chikungunya, Zika, West Nile, and Mayaro, a dengue-like disease. Oxitec genetically engineered the males of this species to carry a “genetic kill switch.” When they mate with wild female mosquitoes, their offspring inherit the lethal gene, and they cannot survive or reproduce in the wild. Oxitec is marketing these insects as “Oxitec Friendly” mosquitoes in the U.S.
Suppression Trial through an Integrated Vector Management of Aedes albopictus (Skuse) Based on the Sterile Insect Technique in a Non-Isolated Area in Spain
27563C. Tur, D. Almenar, M. Zacarés, S. Benlloch-Navarro, I. Pla and V. Dalmau, Insects, 14. 2023-08-03 07:16:56.
In recent years, Aedes albopictus (Skuse, 1984) has expanded its distribution globally due to its high ecological plasticity. This expansion has increased the population’s susceptibility to contracting diseases such as dengue, Zika, and chikungunya, among others, which are transmitted by this mosquito species. In the absence of effective control methods, the application of the sterile insect technique (SIT) is proposed as part of an integrated vector management (IVM) program. From 2007 to 2020, this strategy has been tested in a non-isolated mosquito population urban area of 45 ha, representative of the municipalities of the Valencian region (Spain). The population levels of adult females and eggs collected in the traps have been reduced by 70–80% compared to the control area, demonstrating its efficacy in reducing mosquito populations. This work analyzes the impact of the migration of the wild mosquito population from the peri-urban area to the urban core.
Effects of γ-Irradiation on Mating Behavior of Red Palm Weevil, Rhynchophorus ferrugineus (Olivier, 1790) (Coleoptera: Dryophthoridae)
27600M. Cristofaro, C. Fornari, F. Mariani, A. Cemmi, M. Guedj, M. L. Ben Jamaa, M. Msaad Guerfali, E. Tabone, R. Castellana, R. Sasso and S. Musmeci, Insects, 14. 2023-07-24 07:00:32.
Red palm weevil (RPW) Rhynchophorus ferrugineus (Olivier 1790) is a highly invasive species originating from Southeast Asia and Melanesia. Over the past 30 years, this alien pest has spread extensively in the Middle East and the Mediterranean basin. Its endophagous larvae feed on various palm species, causing significant damage that leads to the death of palm trees. Controlling RPW infestations is challenging due to their gregarious nature and the lack of detectable early symptoms. Systemic insecticides are effective means of control, but their use in urban areas is prohibited and resistance can develop. Considering alternative options with minimal environmental impact, the Sterile Insect Technique (SIT) has been explored. Previous research has shown that male RPWs irradiated at 80 Gy or higher achieve full sterility. This study aimed to investigate in laboratory conditions whether RPW sterile males (irradiated at 60 and 80 Gy) could compete sexually with non-irradiate males. Laboratory bio-assays under both no-choice and choice conditions assessed sexual performance in terms of number of matings, mating duration and time elapsed until the first mating. The results confirmed that irradiation does not negatively affect the mating performance of sterile males, demonstrating their ability to compete successfully with non-irradiated males in both experimental setups.
Cost-effectiveness of Precision Guided SIT for Control of Anopheles gambiae in the Upper River Region, The Gambia
27060G. William, R. Robyn, M. Agastya, M. S. C. Hector, S. Andrea, Z. David, G. I. Patrick, D. Umberto, Alessandro, M. M. John and A. Omar, bioRxiv, 2023.07.20.549762. 2023-07-22 06:41:45.
Precision-guided sterile insect technique (pgSIT) is an extremely promising vector control intervention that can reduce and potentially eliminate the unacceptable malaria burden, particularly in sub-Saharan Africa. Here we explore the cost effectiveness of using this approach in Africa using mathematical modeling and economical analysis. Overall, we find that pgSIT represents a cost-effective and promising approach to A. gambiae control in The Gambia, with the potential to deliver significant economic and social benefits.Competing Interest StatementThis work was supported by funding from an Open Philanthropy award (309937-0001). The views, opinions, and/or findings expressed are those of the authors and should not be interpreted as representing the official views or policies of the U.S. government. Figures were created using www.BioRender.com.
Eliminating Malaria Vectors with Precision Guided Sterile Males
27058L. S. Andrea, A. A. Reema, J. P. James, L. C. Martha, C. Sanle, M. Agastya, M. S. C. Hector, A. Igor, M. M. John and S. A. Omar, bioRxiv, 2023.07.20.549947. 2023-07-21 06:35:41.
Controlling the principal African malaria vector, the mosquito Anopheles gambiae, is considered essential to curtail malaria transmission. However existing vector control technologies rely on insecticides, which are becoming increasingly ineffective. Sterile insect technique (SIT) is a powerful suppression approach that has successfully eradicated a number of insect pests, yet the A. gambiae toolkit lacks the requisite technologies for its implementation. SIT relies on iterative mass-releases of non-biting, non-driving, sterile males which seek out and mate with monandrous wild females. Once mated, females are permanently sterilized due to mating-induced refractoriness, which results in population suppression of the subsequent generation. However, sterilization by traditional methods renders males unfit, making the creation of precise genetic sterilization methods imperative. Here we develop precision guided Sterile Insect Technique (pgSIT) in the mosquito A. gambiae for inducible, programmed male-sterilization and female-elimination for wide scale use in SIT campaigns. Using a binary CRISPR strategy, we cross separate engineered Cas9 and gRNA strains to disrupt male-fertility and female-essential genes, yielding >99.5% male-sterility and >99.9% female-lethality in hybrid progeny. We demonstrate that these genetically sterilized males have good longevity, are able to induce population suppression in cage trials, and are predicted to eliminate wild A. gambiae populations using mathematical models, making them ideal candidates for release. This work provides a valuable addition to the malaria genetic biocontrol toolkit, for the first time enabling scalable SIT-like confinable suppression in the species.Competing Interest StatementO.S.A is a founder of Agragene, Inc. and Synvect, Inc. with equity interest. The terms of this arrangement have been reviewed and approved by the University of California, San Diego in accordance with its conflict of interest policies. All other authors declare no competing interests.
Bukedi sub-region to receive new high-level malaria prevention technology
26950Watchdog Uganda, WATCHDOG, 2023-07-20 08:51:14.
President Yoweri Kaguta Museveni together with a group of scientists have agreed to start with Bukedi Sub-region as a pilot area for a new mosquito radiation sterilisation technology aimed at preventing malaria. “Let us start with the Bukedi Sub- region to pilot this method since the area has got a lot of water, flat area, and stagnant water. This will help us solve the problem of mosquitoes and have less patients,” President Museveni noted. Speaking during a meeting at State House, Entebbe yesterday, the President said if the study works out in Bukedi, the technology will then be spread to other areas around the country. “Sterilisation of the male mosquitoes or tsetse flies is something we have been talking about for a long time. But now, you have come, good, I support it, go ahead and have like a pilot effort which will result into a study and conclusion,” he appealed.
Population suppression by release of insects carrying a dominant sterile homing gene drive targeting doublesex in Drosophila
26903C. Weizhe, G. Jialiang, L. Yiran and C. Jackson, bioRxiv, 2023.07.17.549342. 2023-07-17 11:00:13.
Gene drive alleles, which bias their own inheritance and increase in frequency, show great promise for blocking disease transmission or directly suppressing pest populations. The most common engineered drive system is the CRISPR homing drive, which converts wild-type alleles to drive alleles in the germline of drive heterozygotes by homology-directed repair after CRISPR cleavage. One successful homing drive example targets a female-specific exon in doublesex in Anopheles mosquitos, suppressing the population by inducing recessive sterility in female drive homozygotes. We found that in Drosophila melanogaster, a 3-gRNA drive disrupting the doublesex female exon resulted in a masculine phenotype and dominant female sterility. Resistance alleles formed by end-joining repair were also dominant sterile. This was likely caused by expression of male-specific transcripts in females with drive and resistance alleles, disrupting sex development. Based on this construct, we proposed a new pest suppression system called Release of Insects carrying a Dominant-sterile Drive (RIDD). This entails continuously releasing drive heterozygous males, with drive and resistance alleles causing sterility in females. The drive remains at high frequency longer than currently used dominant female-lethal alleles (RIDL) due to drive conversion in males, and drive alleles also cause sterility based on resistance, both substantial advantages. With weekly releases of drive males into a cage population with overlapping generations, our RIDD system targeting dsx reached 100% prevalence within 27 weeks, progressively reducing egg production and eventually causing total population collapse. RIDD combines the merits of homing gene drive and RIDL. It is powerful but self-limiting, unlike unconfined standard homing drives, allowing for targeted population suppression.Competing Interest StatementThe authors have declared no competing interest.
CRISPR’d Mosquitoes With All-Male Offspring Could Help Eradicate Malaria
26610V. B. Ramirez, Singuarity Hub, 2023-07-13 13:17:26.
Though at least one vaccine for malaria is in use, it remains one of the deadliest diseases in the world. Almost half of the world’s population lives in areas where malaria transmission occurs, and an estimated 619,000 people died of the disease in 2021. Worse yet, the vast majority of cases leading to death are in young children. Researchers from the University of California in San Diego may have found a way to reduce this burden of disease. They used the gene editing tool CRISPR to alter a gene that controls sexual development in mosquitoes. Male mosquitoes don’t bite humans; it’s the females that spread malaria and other diseases. The UCSD team’s method uses gene editing to kill all female mosquito offspring within a given population of the insects. The mosquito species in question is Anopheles gambiae, commonly called the African malaria mosquito and described as “the most efficient vector of human malaria.” They’re anthropophilic, meaning they like human blood more than animal blood, and they thrive in hot climates with a lot of moisture. Why such an insect exists in the first place is hard to comprehend, is it not?
Optimization of Dieldrin Selection for the Genetic Sexing of Aedes albopictus
26598S. Scussel, B. Gaudillat, J. Esnault, Q. Lejarre, M. Duployer, D. Messaoudi, P. Mavingui, P. Tortosa and J. Cattel, Insects, 14. 2023-07-13 12:55:46.
The mass production of mosquitoes at an industrial scale requires efficient sex separation, which can be achieved through mechanical, genetic or artificial intelligence means. Compared with other methods, the genetic sexing approach offers the advantage of limiting costs and space by removing females at the larval stage. We recently developed a Genetic Sexing Strain (GSS) in Aedes albopictus based on the sex linkage of the rdlR allele, conferring resistance to dieldrin, to the male (M) locus. It has been previously reported that dieldrin ingested by larvae can be detected in adults and bioaccumulated in predators, raising the question of its use at a large scale. In this context, we performed several experiments aiming at optimizing dieldrin selection by decreasing both dieldrin concentration and exposure time while maintaining a stable percentage of contaminating females averaging 1%. We showed that the previously used dieldrin exposure induced an important toxicity as it killed 60% of resistant males at the larval stage. We lowered this toxicity by reducing the dose and/or the exposure time to recover nearly all resistant males. We then quantified the residues of dieldrin in resistant male adults and showed that dieldrin toxicity in larvae was positively correlated with dieldrin concentrations detected in adults. Interestingly, we showed that the use of reduced dieldrin exposure led to a dieldrin quantification in adult males that was below the quantity threshold of the Gas Chromatography-Mass Spectrometry detection method. Presented data show that dieldrin exposure can be adjusted to suppress toxicity in males while achieving efficient sexing and lowering the levels of dieldrin residues in adults to barely quantifiable levels.
New Study Improves Sterile Insect Technique for Mosquitoes
26600E. Ricciuti, Entomology Today, 2023-07-12 12:59:23.
As Florida health authorities work to respond to an ever-growing cadre of invasive tropical mosquitoes, a research team has sharpened an environmentally friendly tool increasingly deployed against a dangerous species that invaded the state two centuries ago. The mosquito is Aedes aegypti, vector of yellow fever, dengue fever, chikungunya, and Zika fever. It is one of the mosquitoes increasingly targeted with the sterile insect technique (SIT), in which male insects reared en masse are sterilized by gamma-ray or x-ray ionization and released to mate with wild females, which then produce non-viable eggs. Besides being environmentally innocuous, SIT is not hindered by insecticide resistance, a huge plus for pest managers. Long used against flies and other agricultural insect pests, SIT has shown promise against disease vectors such as mosquitoes, but a few wrinkles have kept it from reaching full potential. Research on Aedes aegypti described in a new study published in June in the Journal of Medical Entomology has smoothed the process, showing that the success of SIT can be measurably enhanced if male mosquitoes are sterilized when they emerge as adults, rather than as pupae, the approach now in use.
The Effect of X-ray Irradiation on the Fitness and Field Adaptability of the Codling Moth: An Orchard Study in Northeast China
26544J. Zhang, S. Huang, S. Zhao, X. Wang, X. Yang, H. Zhao, P. Gao, Y. Li and X. Yang, Insects, 14. 2023-07-07 08:43:03.
The codling moth, Cydia pomonella (L.), is an invasive agricultural pest of pome fruits and walnuts in China that threatens the apple industry in the Loess Plateau and Bohai Bay; it has developed resistance to many insecticides. Sterile insect technique (SIT) combined with area-wide integrated pest management (AW-IPM) can reduce the risk of resistance to insecticides and effectively control some insect pest species. Our previous laboratory experiment found that irradiation with 366 Gy of X-ray caused the males of the codling moth to become sterile. However, the sterility and adaptability of males after being irradiated with 366 Gy X-ray in the field are still unclear. In this study, we investigated the effect of X-ray irradiation on the fitness of male adults that emerged from pupae irradiated with 366 Gy to explore their adaptability and mating competitiveness, and to examine the effect of releasing sterile male insects in orchards in northeast China on the fruit infestation rate of the Nanguo pear. The results showed that 366 Gy of X-ray irradiation significantly reduced the mating competitiveness of males and the hatching rate of the eggs laid by females pairing with sterile males. Meanwhile, the lifespan of the sterile male moths was significantly shorter than that of the normal ones in the field. A pilot test showed that the release twice of sterile male moths in the orchards had no significant effect on the fruit infestation rate. Our field experiments provide a scientific basis for the further optimization of the SIT technology program for controlling C. pomonella.
New Genetic Technology Developed to Halt Malaria-Spreading Mosquitoes
26473M. Aguilera, UC San Diego Today, 2023-07-05 08:09:31.
Fortunately, scientists are developing safe technologies to stop the transmission of malaria by genetically editing mosquitoes that spread the parasite that causes the disease. Researchers at the University of California San Diego led by Professor Omar Akbari’s laboratory have engineered a new way to genetically suppress populations of Anopheles gambiae, the mosquitoes that primarily spread malaria in Africa and contribute to economic poverty in affected regions. The new system targets and kills females of the A. gambiae population since they bite and spread the disease. Publishing July 5 in the journal Science Advances, first-author Andrea Smidler, a postdoctoral scholar in the UC San Diego School of Biological Sciences, along with former master’s students and co-first authors James Pai and Reema Apte, created a system called Ifegenia, an acronym for “inherited female elimination by genetically encoded nucleases to interrupt alleles.” The technique leverages the CRISPR technology to disrupt a gene known as femaleless (fle) that controls sexual development in A. gambiae mosquitoes.
Scientists are Gene-Editing Flies to Fight Crop Damage
26310E. Mullin, WIRED, 2023-06-28 07:28:35.
In greenhouses in Oregon last month, researchers with the US Department of Agriculture began testing one such approach: sterilized male flies. The gene-edited bugs, made by St. Louis–based biotech company Agragene, are meant to suppress wild fly populations. The idea is that if they were to be released into the environment, the sterilized males would mate with wild females, resulting in a fertility dead end. “We see this technology as being able to provide healthier fruit and vegetables without doing a lot of harm to the environment,” says Agragene CEO Bryan Witherbee. Scientists at the company used the DNA editing tool Crispr to knock out two essential genes in fly embryos—one involved in male reproduction and another with female development. As a result, only sterile males hatch while the females die. “You don’t want to release females into the population, because those are the ones that are doing the damage,” says Stephanie Gamez, director of research and development at Agragene.
Nuclear Technique Used in Europe for First time to Battle Yellow Fever Mosquito Found in Cyprus
26314IAEA, IAEA, 2023-06-27 07:43:22.
Cyprus this month released the first batch of 100,000 sterile mosquitos to begin the implementation of a Food and Agriculture Organization (FAO) and International Atomic Energy Agency (IAEA) project testing the use of a nuclear technique to eradicate an invasive species of mosquitoes found in the country.Cyprus confirmed the presence of the Aedes aegypti mosquito, also called Yellow Fever mosquito, on the island in 2022. This species of mosquito can carry serious vector-borne diseases such as chikungunya, dengue, yellow fever and Zika. The Aedes albopictus - also a carrier for such diseases - was also confirmed to be present on the island in 2022. Vector-borne diseases cause over 700,000 global deaths per year and the presence of the two species poses an immediate threat to Cyprus’ economy and healthcare system in case of a disease outbreak.
Developing methods for chilling, compacting, and sterilizing adult Aedes aegypti (Diptera: Culicidae) and comparing mating competitiveness between males sterilized as adults versus pupae for sterile male release
26602D. A. Tussey, R. Morreale, D. O. Carvalho, S. Stenhouse, A. M. Lloyd, D. F. Hoel and D. A. Hahn, Journal of Medical Entomology, 2023-06-21 13:03:55.
The yellow fever mosquito, Aedes aegypti L., can transmit several pathogens responsible for human diseases. With insecticide resistance development becoming a concern, alternative control strategies are needed for Ae. aegypti. Sterile insect technique (SIT) is an increasingly popular option being explored. However, logistical issues in mass production and sterilization make it difficult to maintain a SIT program. Male mosquitoes are typically irradiated as pupae because this is the earliest developmental point at which females can be separated from males, but asynchrony in pupation and high variability in pupal responses to irradiation based on pupal age make it difficult to sterilize mass quantities of pupae on a regular schedule in a rearing facility. Young adult mosquitoes have wider windows for irradiation sterilization than pupae, which can allow facilities to have fixed schedules for irradiation. We produced a workflow for adult Ae. aegypti irradiation in a mosquito control district with an operational SIT program that currently irradiates pupae. The impacts of chilling, compaction, and radiation dose on survival were all assessed before combining them into a complete adult irradiation protocol. Males chilled up to 16 h prior to compaction and compacted to 100 males/cm3 during radiation resulted in low mortality. Males irradiated as adults had increased longevity and similar sterility compared to males irradiated as pupae. Additionally, males sterilized as adults were more sexually competitive than males sterilized as pupae. Thus, we have shown that irradiating adult males can be a viable option to increase the efficiency of this operational mosquito SIT program.
Effects of radiation on the fitness, sterility and arbovirus susceptibility of a Wolbachia-free Aedes albopictus strain for use in the Sterile Insect Technique
25867D. J. Zhang, S. Yan, H. Yamada, Y. Wu, G. Wang, Q. D. Feng, D. Paerhande, H. Maiga, J. Bouyer, J. Qian, Z. D. Wu and X. Y. Zheng, Pest Management Science, 2023-06-15 08:49:29.
BACKGROUND: The sterile insect technique (SIT) is a green and species-specific insect pest control technique that suppresses target populations by releasing factory-reared, radio-sterilized males into the wild. Once released, it is important to be able to distinguish the released males from the wild males for monitoring purposes. Several methods to mark the sterile males exist. However, most have limitations due to monetary, process efficiency, or insect quality. Aedes albopictus is naturally infected with Wolbachia at a high prevalence. Therefore, the elimination of Wolbachia can serve as a biomarker to distinguish the factory-reared male mosquitoes from wild conspecifics. RESULTS: In this study, a Wolbachia-free Ae. albopictus GT strain was developed and its fitness evaluated, which was found to be comparable to the wild GUA strain. In addition, GT male mosquitoes were irradiated at the adult stage and a dose of 20 Gy or more induced over 99% sterility. Moreover, a dose of 30 Gy (almost completely sterilizing male and female mosquitoes) had limited effects on the mating competitiveness of GT males and vector competence of GT females, respectively. However, radiation reduced mosquito longevity, regardless of its sex. CONCLUSION: Our results indicated that the Ae. albopictus GT strain can be distinguished from the wild mosquitoes based on Wolbachia status and shows similar fitness, radio-sensitivity and arbovirus susceptibility to the GUA strain, indicating that it is feasible to use the GT strain to suppress Ae. albopictus populations for SIT programmes. This article is protected by copyright. All rights reserved.
Sequence and expression analysis of the spermatogenesis-specific gene cognates, wampa and Prosα6T, in Drosophila suzukii
26182Q. Xia, K. Tariq, D. A. Hahn and A. M. Handler, Genetica, 2023-06-10 12:20:00.
The sterile insect technique (SIT) is a highly effective biologically-based method for the population suppression of highly invasive insect pests of medical and agricultural importance. The efficacy of SIT could be significantly enhanced, however, by improved methods of male sterilization that avoid the fitness costs of irradiation. An alternative sterilization method is possible by gene-editing that targets genes essential for sperm maturation and motility, rendering them nonfunctional, similar to the CRISPR-Cas9 targeting of β2-tubulin in the genetic model system, Drosophila melanogaster. However, since genetic strategies for sterility are susceptible to breakdown or resistance in mass-reared populations, alternative targets for sterility are important for redundancy or strain replacement. Here we have identified and characterized the sequence and transcriptional expression of two genes in a Florida strain of Drosophila suzukii, that are cognates of the D. melanogaster spermatocyte-specific genes wampa and Prosalpha6T. Wampa encodes a coiled-coil dynein subunit required for axonemal assembly, and the proteasome subunit gene, Prosalpha6T, is required for spermatid individualization and nuclear maturation. The reading frames of these genes differed from their NCBI database entries derived from a D. suzukii California strain by 44 and 8 nucleotide substitutions/polymorphisms, respectively, though all substitutions were synonymous resulting in identical peptide sequences. Expression of both genes is predominant in the male testis, and they share similar transcriptional profiles in adult males with β2-tubulin. Their amino acid sequences are highly conserved in dipteran species, including pest species subject to SIT control, supporting their potential use in targeted male sterilization strategies. © 2023, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.
How aggressive interactions with biomimetic agents optimize reproductive performances in mass-reared males of the Mediterranean fruit fly
25553D. Romano, G. Benelli and C. Stefanini, Biological Cybernetics, 2023-06-09 08:59:21.
Mass-rearing procedures of insect species, often used in biological control and Sterile Insect Technique, can reduce the insects competitiveness in foraging, dispersal, and mating. The evocation of certain behaviours responsible to induce specific neuroendocrine products may restore or improve the competitiveness of mass-reared individuals. Herein, we used a mass-reared strain of Ceratitis capitata as model organism. C. capitata is a polyphagous pest exhibiting territorial displays that are closely related to its reproductive performance. We tested if the behaviour of C. capitata males could be altered by hybrid aggressive interactions with a conspecific-mimicking robotic fly, leading to more competitive individuals in subsequent mating events. Aggressive interactions with the robotic fly had a notable effect on subsequent courtship and mating sequences of males that performed longer courtship displays compared to naïve individuals. Furthermore, previous interactions with the robotic fly produced a higher mating success of males. Reproductive performances of C. capitata males may be improved by specific octopaminergic neurones activated during previous aggressive interactions with the robotic fly. This study adds fundamental knowledge on the potential role of specific neuro-behavioural processes in the ecology of tephritid species and paves the way to innovative biotechnological control methods based on robotics and bionics.
Molecular detection of reproductive symbionts and parthenogenesis experiments in Tuta absoluta from Argentina: facing potential for sustainable and specific pest control strategies
26184C. Cagnotti, C. Conte, J. Kramar, S. Lanzavecchia and S. López, Entomologia Experimentalis et Applicata, 2023-06-07 12:24:43.
Tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a key pest of tomato crops. Specific and environmentally friendly control strategies against this pest, such as the sterile insect technique (SIT), are under development and sexual reproduction has emerged as a key focal point to ensure its success. In the present study, we analyzed four representative T. absoluta populations from Argentina, focusing on the molecular detection of endosymbionts potentially associated with reproductive abnormalities and on determining whether parthenogenesis can occur under laboratory conditions. Larvae of T. absoluta were collected in commercial tomato plantations from La Plata and Mar del Plata (both in Buenos Aires province), Bella Vista (Corrientes province), and Yuto (Jujuy province). Tuta absoluta adults were evaluated by standard PCR for the presence of reproductive endosymbionts (Wolbachia sp., Spiroplasma sp., Arsenophonus sp., Cardinium sp., and Rickettsia sp.). For parthenogenesis assays, 20–23 virgin females from each T. absoluta geographic population were life-long isolated in Petri dishes with a tomato leaf. Fecundity, fertility, and female longevity were estimated and compared with results from mated females from each population. Our results showed the presence of a unique endosymbiont (Wolbachia sp. supergroup B, sequence type 41). Fecundity of the unmated females was significantly lower than fecundity of mated females in all T. absoluta populations. In addition, unmated females only laid infertile eggs. In conclusion, the absence of parthenogenesis in T. absoluta from representative geographic populations supports the implementation of SIT and mating disruption as effective control strategies against this pest in Argentina. © 2023 Netherlands Entomological Society.
CRISPR-based gene editing of non-homologous end joining factors biases DNA repair pathway choice toward single-strand annealing in Aedes aegypti
25461K. Chae, J. M. Overcash, C. Dawson, C. Valentin, H. Tsujimoto, K. M. Myles and Z. N. Adelman, Current Research in Biotechnology, 5:100133. 2023-05-29 08:04:22.
To maintain genome stability, eukaryotic cells orchestrate DNA repair pathways to process DNA double-strand breaks (DSBs) that result from diverse developmental or environmental stimuli. Bias in the selection of DSB repair pathways, either non-homologous end joining (NHEJ) or homology-directed repair (HDR), is also critical for efficient gene editing and for homing-based gene drive approaches developed for the control of disease-transmitting vector mosquitoes. However, little is understood about DNA repair homeostasis in the mosquito genome. Here, we utilized CRISPR/Cas9 to generate indel mutant strains for core NHEJ factors ku80, DNA ligase IV (lig4), and DNA-PKcs in the mosquito Aedes aegypti and evaluated the corresponding effects on DNA repair. In a plasmid-based assay, disruption of ku80 or lig4, but not DNA-PKcs, reduced both NHEJ and SSA. However, a transgenic reporter strain-based test revealed that those mutations significantly biased DNA repair events toward SSA. Interestingly, ku80 mutation also significantly increased the end joining rate by a yet-characterized mechanism in males. Our study provides evidence that the core NHEJ factors have an antagonistic effect on SSA-based DSB repair of the Ae. aegypti genome. Down-modulating the NHEJ pathway can enhance the efficiency of nuclease-based genetic control approaches, as most of those operate by homology-based repair processes along with extensive DNA end resection that is antagonized by NHEJ.
Oxitec Launches New Technology Program to Develop a Friendly™ Solution for the World’s Most Damaging Cattle Tick
25292Oxitec Ltd, Oxitec Press Release, 2023-05-24 07:45:30.
Oxitec Ltd, the leading developer of insect-based biological solutions to control pests that transmit disease, destroy crops and harm livestock, today announced the launch of development of a targeted, biological Friendly™ solution for the world’s most devastating cattle pest, the Asian blue tick, or Rhipicephalus microplus. In a feasibility project funded by the Bill & Melinda Gates Foundation, Oxitec’s team validated the key methods for development of a Friendly™ R. microplus, and found that, for management of this dangerous tick, this biological approach is anticipated to provide a highly effective alternative to chemical pesticides. The Foundation has now committed $4.8 million to an early development phase to start to build the Friendly™ R. microplus solution, Oxitec’s first targeting a non-insect pest.
Near-infrared imaging for automated tsetse pupae sex sorting in support of the sterile insect technique
25472R. Argilés-Herrero, G. Salvador-Herranz, A. G. Parker, M. Zacarés, A. G. Fall, A. M. Gaye, A. Nawaz, P. Takáč, M. J. B. Vreysen and C. J. de Beer, Parasite, 30. 2023-05-17 08:49:45.
Tsetse flies are the cyclical vectors of African trypanosomes and one of several methods to manage this vector is the sterile insect technique (SIT). The ability to determine the sex of tsetse pupae with the objective to separate the sexes before adult emergence has been a major goal for decades for tsetse management programmes with an SIT component. Tsetse females develop faster and pharate females inside the pupae melanise 1–2 days before males. This earlier melanisation can be detected by infrared cameras through the pupal shell, and the newly developed Near InfraRed Pupae Sex Sorter (NIRPSS) takes advantage of this. The melanisation process is not homogeneous for all fly organs and the pupa needs to be examined ventrally, dorsally and laterally to ensure accurate classification by an image analysis algorithm. When the pupae are maturing at a constant temperature of 24 °C and sorted at the appropriate age, 24 days post-larviposition for Glossina palpalis gambiensis, the sorting machine can efficiently separate the sexes. The recovered male pupae can then be sterilised for field releases of males, while the rest of the pupae can be used to maintain the laboratory colony. The sorting process with the new NIRPSS had no negative impact on adult emergence and flight ability. A mean male recovery of 62.82 ± 3.61% was enough to provide sterile males to an operational SIT programme, while mean contamination with females (4.69 ± 3.02%) was low enough to have no impact on the maintenance of a laboratory colony
Scientists in Tahiti prepare to release sterilized mosquitoes to control dengue
26192F. Fouque, WHO TDR, 2023-05-16 12:42:52.
Scientists in Tahiti have launched a research project to test the Sterile Insect Technique (SIT) in French Polynesia, where the impact of the technology on dengue transmission will be measured for the first time. This is part of a global research initiative supported by TDR, (the Special Programme for Research and Training in Tropical Diseases), the International Atomic Energy Agency (IAEA), the World Health Organization (WHO), and the U.S. Centers for Disease Control and Prevention (CDC), to trial innovative, environmentally friendly solutions to disease control.
Editorial: Genetic control of insect pest species—achievements, challenges, and perspectives
25423I. Häcker, D. Bartsch, A. Choo and F. Marec, Frontiers in Bioengineering and Biotechnology, 11. 2023-05-05 08:12:07.
Genetic control is a type ofbiological control and a promising approach to regulate insect pest populations in a species-specific manner. It is based on targeting the reproductive capacity of the target pest species to reduce population size to non-critical levels. The best known and also very successful genetic control strategy is the Sterile Insect Technique (SIT), which entails the continuous mass-release ofirradiation-sterilized males ofa given species to produce infertile matings in the field, leading to the decline in the target population over time. To date, SIT is only available for a few species, as its transfer to new target species is challenging and time consuming. Key aspects of this classical SIT and challenges in applying it to new pest species include mass rearing of target species, mass removal of female insects prior to irradiation and release, the sterilization procedure, and the biological quality control of the sterile insects produced. Besides this classical SIT strategy, current research efforts are also focused on the development of genetic control approaches based on transgenic, symbiont-mediated, or gene-drive strategies. Modern genetic technologies offer new solutions for the improvement of existing genetic control strategies and insect strains, for faster and easier transfer of existing strategies to new target species, and also for the development of new genetic control approaches. Publications within this Research Topic address pressing questions and challenges related to the genetic control of insect pests.
The Role of Symbiont-Targeted Strategies in the Management of Pentatomidae and Tephritidae Pests under an Integrated Vision
24996E. Gonella and A. Alma, Agronomy, 13. 2023-04-21 15:11:32.
The interaction between insects and gut bacterial symbionts is, nowadays, regarded as an important element in the implementation of pest management, in consideration of the urgent need for sustainable alternatives to insecticide use. In this framework, a major tool is symbiotic control, with the main ready-to-use application represented by the interruption of obligate symbioses. Two insect families, namely Pentatomidae in the Hemiptera order and Tephritidae in Diptera, have been indicated as outstanding targets for symbiont-oriented control tactics. An important advantage of interrupting obligate symbioses is the target shift from insect to bacteria, which avoids insecticide use; however, the compatibility between this approach and other pest/disease management strategies is crucial to design low-impact pest control programs. Here we present the state of knowledge regarding the integration of symbiont manipulation in sustainable plant protection plans. Research assessing the potential for multitarget applications is reported, as well as studies on the impact of symbiont interruption on nontarget species. Besides symbiont-targeted pest control, another relevant outcome of symbiont manipulation is the restoration of microbial perturbation in mass-reared insects used in pest control programs, which is a required step to allow the success of other tactics, such as the Sterile Insect Technique. Despite the potential contribution that symbiont-targeted strategies may offer to integrated pest management, we point out that operational caveats may emerge in symbiont-oriented control in relation to the target extension on the label directions and to the number of required treatments. Future work is needed to increase the target range and the number of tested formulations exploiting the interruption of bacterial symbioses. This will also require assessment of the effect of different products on beneficial organisms, including biological control agents. Finally, the authorization of formulates for symbiotic control should be taken into consideration by the regulatory bodies, to really promote new readily available control options. © 2023 by the authors.
Standardization of sterile insect technique (SIT) for melon fruit fly
25144M. Math and Y. K. Kotikal, Journal of Entomological Research, 47:16-20. 2023-04-21 14:26:32.
Sterile technique was standardized for melon fly, Zeugodacus cucurbitae Coquillett under laboratory conditions. The Adult emergence of B. cucurbitae was significantly highest (96.12%) without radiation to the pupae. Among different radiation doses, 30 Gy resulted in significantly the highest adult emergence (64.12%). Significantly the highest deformed adults were observed at 90 Gy (10.61%) while, it was lowest without radiation (1.33%). When mature pupae were exposed to 30, 50, 70 and 90 Gy the male longevity was 32.37, 26.55, 24.57 and 20.63 days, respectively, as against 34.98 days for untreated males. At 90 Gy mating competitive values recorded was 5.66 and 8.29 with a treated male: Untreated male: Untreated female cross ratio of 2:1:1 and 1:2:1, respectively. Significantly the highest per cent sterility of Z. cucurbitae was recorded at 90 Gy with a cross ratio of 2:1:1 and 1:1:2 (68.36 and 55.28%, respectively). © 2023, Journal of Entomological Research. All Rights Reserved.
Targeting Sex Determination to Suppress Mosquito Populations
24988L. Ming, P. K. Nikolay, S. Ruichen, Y. Ting, D. B. Elena, J. B. Daniel, A. Igor, M. S. C. Hector, Z. Yinpeng, A. D. Nicolas, M. L. YuMin, P. S. Matthew, M. Craig, M. M. John and S. A. Omar, bioRxiv, 2023.04.18.537404. 2023-04-20 14:45:03.
Each year, hundreds of millions of people are infected with arboviruses such as dengue, yellow fever, chikungunya, and Zika, which are all primarily spread by the notorious mosquito Aedes aegypti. Traditional control measures have proven insufficient, necessitating innovations. In response, here we generate a next generation CRISPR-based precision-guided sterile insect technique (pgSIT) for Aedes aegypti that disrupts genes essential for sex determination and fertility, producing predominantly sterile males that can be deployed at any life stage. Using mathematical models and empirical testing, we demonstrate that released pgSIT males can effectively compete with, suppress, and eliminate caged mosquito populations. This versatile species-specific platform has the potential for field deployment to control wild populations, safely curtailing disease transmission.Competing Interest StatementO.S.A. is a founder of Agragene, Inc. with equity interest. O.S.A., M.L., and N.P.K are founders of Synvect with equity interest. The terms of this arrangement have been reviewed and approved by the University of California, San Diego in accordance with its conflict of interest policies. All remaining authors declare no competing interests.
Evaluating the Effect of Irradiation on the Densities of Two RNA Viruses in Glossina morsitans morsitans
25137C. K. Mirieri, A. M. M. Abd-Alla, V. I. D. Ros and M. M. van Oers, Insects, 14. 2023-04-20 14:11:24.
Tsetse flies are cyclic vectors of Trypanosoma parasites, which cause debilitating diseases in humans and animals. To decrease the disease burden, the number of flies is reduced using the sterile insect technique (SIT), where male flies are sterilized through irradiation and released into the field. This procedure requires the mass rearing of high-quality male flies able to compete with wild male flies for mating with wild females. Recently, two RNA viruses, an iflavirus and a negevirus, were discovered in mass-reared Glossina morsitans morsitans and named GmmIV and GmmNegeV, respectively. The aim of this study was to evaluate whether the densities of these viruses in tsetse flies are affected by the irradiation treatment. Therefore, we exposed tsetse pupae to various doses (0–150 Gy) of ionizing radiation, either in air (normoxia) or without air (hypoxia), for which oxygen was displaced by nitrogen. Pupae and/or emerging flies were collected immediately afterwards, and at three days post irradiation, virus densities were quantified through RT-qPCR. Generally, the results show that irradiation exposure had no significant impact on the densities of GmmIV and GmmNegeV, suggesting that the viruses are relatively radiation-resistant, even at higher doses. However, sampling over a longer period after irradiation would be needed to verify that densities of these insect viruses are not changed by the sterilisation treatment. © 2023 by the authors.
The Effect of the Sterile Insect Technique on Vibrational Communication: The Case of Bagrada hilaris (Hemiptera: Pentatomidae)
24951C. Peccerillo, C. E. Mainardi, R. Nieri, J. M. Fouani, A. Cemmi, M. Cristofaro, G. Anfora and V. Mazzoni, Insects, 14. 2023-04-02 13:09:28.
The painted bug, Bagrada hilaris, is an agricultural pest in its original areas (Africa, South Asia, and the Middle East), and it has recently been recorded as an invasive species in southwestern part of the US, Chile, Mexico, and two islands in the Mediterranean basin. Its polyphagous diet causes severe damage to economically important crops. The control of this pest is primarily achieved by means of synthetic pesticides, which are often expensive, ineffective, and harmful to the ecosystem. Recent physiological bioassays to assess its potential control through the sterile insect technique demonstrated that mating between untreated females and males irradiated at doses of 64 and 100 Gy, respectively, resulted in 90% and 100% sterility of the eggs produced by the females. In this study, the mating abilities of virgin males irradiated at 60 and 100 Gy with virgin females were measured through a study of short-range courtship mediated by vibrational communication. The results indicate that males irradiated at 100 Gy emit signals with lower peak frequencies, mate significantly less than unirradiated males do, and do not surpass the early stages of courtship. Conversely, males irradiated at 60 Gy present vibrational signal frequencies that are comparable to those of the control and successfully mated males. Our findings suggest that B. hilaris individuals irradiated at 60 Gy are good candidates for the control of this species, given that they retain sexual competitiveness regardless of their sterility, through an area-wide program that incorporates the sterile insect technique.
Gamma-radiation of Glossina palpalis gambiensis revisited: effect on fertility and mating competitiveness
24993S. Pagabeleguem, O. Koughuindida, E. W. Salou, G. Gimonneau, A. I. Toé, B. A. Kaboré, K. S. M. Dera, H. Maïga, A. M. G. Belem, G. M. S. Sanou/Ouédraogo, M. J. Vreysen and J. Bouyer, Parasite, 30:8. 2023-03-31 14:58:29.
African animal trypanosomoses are vector-borne diseases that cause enormous livestock losses in sub-Saharan Africa, with drastic socio-economic impacts. Vector control in the context of an area-wide integrated pest management program with a sterile insect technique component requires the production of high-quality sterile male tsetse flies. In our study, we evaluated the effect of irradiation on the fecundity of Glossina palpalis gambiensis to identify the optimal dose that will induce maximum sterility while maintaining biological performance as much as possible. In addition, male mating performance was evaluated in semi-field cages. The irradiation doses used were 90, 100, 110, 120, 130, 140, and 150 Gy, and untreated males were used as the control. The results showed that pupal production and emergence rates were higher in batches of females that had mated with fertile males than in those that had mated with irradiated males with any experimental dose. A dose of 120 Gy administered to male flies induced 97-99% sterility after mating with virgin females. For the semi-field cage experiments, males irradiated with 120 Gy showed good sexual competitiveness as compared to fertile males and those irradiated with 140 Gy, considering the level of filling of spermatheca and the number of pairs formed. The optimal radiation dose of 120 Gy found in this study is slightly different from the traditional dose of 110 Gy that has been used in several eradication programmes in the past. The potential reasons for this difference are discussed, and an argument is made for the inclusion of reliable dosimetry systems in these types of studies.
Improved Quality Management of the Indian Meal Moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) for Enhanced Efficacy of the Sterile Insect Technique
25139M. M. Hasan, M. A. Hossain and C. G. Athanassiou, Insects, 14. 2023-03-31 14:15:48.
The sterile insect technique (SIT) is considered an environmentally friendly, autocidal control tactic to manage insect pests. This work dealt with the improvement of quality management of the Indian meal moth Plodia interpunctella (Hübner) for enhanced efficacy of the SIT. The results indicated that egg hatching of irradiated mature eggs of P. interpunctella was higher than that of younger eggs, indicating that mature eggs were significantly more tolerant than younger eggs. Moreover, our data revealed that a dose of 500 Gy completely prevented pupal formation in irradiated young and mature larvae. Crosses between irradiated and non-irradiated adults resulted in considerable variations in fecundity. The mating competitiveness index (CI) value was higher for a ratio of 5:1:1 (sterile male, fertile male, and fertile female, respectively) as compared with the ratio 1:1:1 for the irradiated individuals of all life stages. Low temperature (5 °C) maintenance of irradiated pupae significantly affected adult emergence. Using cylinders to assess flight ability, we found that the flight performance of adults that were developed from cold treated irradiated pupae was influenced by cylinder diameter, cylinder height and the number of hours the insects were in the cylinders. The percentage of DNA damage of the reproductive organs of adults developed from cold treated pupae that were irradiated with 100 and 150 Gy varied significantly. The results of this study should be used to implement pilot-scale field tests aiming at a sterile- to-fertile male ratio of 5 to 1. © 2023 by the authors.
Groundbreaking Partnership to Combat Dengue Mosquito in the Republic of the Marshall Islands Will Deploy Oxitec Friendly™ Aedes aegypti Solution
24918Oxitec, Oxitec.com, 2023-03-31 13:30:06.
The Republic of the Marshall Islands has selected Oxitec’s Friendly™ Aedes aegypti solution for a new pilot intervention to control the disease-spreading invasive Aedes aegypti mosquito. The project is a partnership between the Republic of the Marshall Islands, the Pacific Island Health Officers’ Association, the US Centers for Disease Control and Prevention, and Oxitec. Aedes aegypti has spread globally and is the primary vector of diseases such as dengue, Zika, chikungunya and yellow fever. Deployments of the Friendly™ Aedes aegypti are planned to be conducted on Ebeye Island where, in 2019, a severe dengue outbreak forced a 'State of Health emergency'.
Additive Effect of Releasing Sterile Insects Plus Biocontrol Agents against Fruit Fly Pests (Diptera: Tephritidae) under Confined Conditions
24928P. Montoya, E. Flores-Sarmiento, P. López, A. Ayala and J. Cancino, Insects, 14. 2023-03-30 13:54:53.
Pest control models integrating the use of the sterile insect technique (SIT) and augmentative biological control (ABC) have postulated that it is possible to obtain a synergistic effect from the joint use of these technologies. This synergistic effect is attributed to the simultaneous attack on two different biological stages of the pest (immature and adult flies), which would produce higher suppression on the pest populations. Here we evaluated the effect of the joint application of sterile males of A. ludens of the genetic sexing strain Tap-7 along with two parasitoid species at the field cage level. The parasitoids D. longicaudata and C. haywardi were used separately to determine their effect on the suppression of the fly populations. Our results showed that egg hatching percentage was different between treatments, with the highest percentage in the control treatment and a gradual reduction in the treatments with only parasitoids or only sterile males. The greatest induction of sterility (i.e., the lowest egg hatching percentage) occurred with the joint use of ABC and SIT, demonstrating that the earlier parasitism caused by each parasitoid species was important reaching high levels of sterility. Gross fertility rate decreased up to 15 and 6 times when sterile flies were combined with D. longicaudata and C. haywardi, respectively. The higher parasitism by D. longicaudata was determinant in the decrease of this parameter and had a stronger effect when combined with the SIT. We conclude that the joint use of ABC and SIT on the A. ludens population had a direct additive effect, but a synergistic effect was observed in the parameters of population dynamics throughout the periodic releases of both types of insects. This effect can be of crucial importance in the suppression or eradication of fruit fly populations, with the added advantage of the low ecological impact that characterizes both techniques.
Paternity Analyses for the Planning of SIT Projects against the Red Palm Weevil
25135S. Belvedere, S. Arnone, M. Cristofaro, A. La Marca and A. De Biase, Insects, 14. 2023-03-28 14:05:49.
The red palm weevil Rhynchophorus ferrugineus is an invasive pest from southeastern Asia and Melanesia that has spread widely across the Middle East and the Mediterranean Basin over the last 30 years. Its endophagous larvae cause huge amounts of damage to several palm tree species from the Arecaceae family. Many of these palms are economically important for agricultural and ornamental purposes. Therefore, a lot of attention has recently been focused on studying this species with the aim of identifying sustainable and effective eradication strategies. Sterile insect techniques are biological control strategies that are currently being investigated for their potential to eradicate this pest in selected invasion areas. Mating system features (e.g., polyandry and related features) can affect the success and suitability of these approaches. The main goal of this research was to assess the performance of a previously developed microsatellite panel in terms of the paternity assignment of progeny from laboratory mating experiments. Using a simulation approach, we evaluated the reliability of the microsatellite markers in the paternity tests both in complex laboratory experiment scenarios and on the progeny of wild-caught gravid females to help future studies on the RPW mating system. As a case study of the simulation results, we performed two double-mating experiments, genotyped the progeny and estimated the P2 values to compare to the expected progeny genotypes according to the crossing scheme of each experiment. The results of our simulations on laboratory experiments showed that it was possible to carry out paternity assignments for all progeny with reliable statistical confidence using our 13 microsatellites set. On the contrary the low genetic variability measured in red palm weevil populations in invaded areas made the resolution power of our loci too low to carry out paternity analyses on natural populations. Results of laboratory crossing were completely congruent with the expectations from the Mendelian laws. © 2023 by the authors.
Vector competence of sterile male Glossina fuscipes fuscipes for Trypanosoma brucei brucei: implications for the implementation of the sterile insect technique in a sleeping sickness focus in Chad
24883M. H. Mahamat, A. Ségard, J.-B. Rayaisse, R. Argiles-Herrero, A. G. Parker, P. Solano, A. M. M. Abd-Alla, J. Bouyer and S. Ravel, Parasites and Vectors, 16:111. 2023-03-22 07:59:24.
Human African trypanosomiasis (HAT) is a neglected tropical disease caused by Trypanosoma brucei gambiense transmitted by tsetse flies in sub‑Saharan West Africa. In southern Chad the most active and persistent focus is the Mandoul focus, with 98% of the reported human cases, and where African animal trypanosomosis (AAT) is also present. Recently, a control project to eliminate tsetse flies (Glossina fuscipes fuscipes) in this focus using the sterile insect technique (SIT) was initiated. However, the release of large numbers of sterile males of G. f. fuscipes might result in a potential temporary increase in transmission of trypanosomes since male tsetse flies are also able to transmit the parasite. The objective of this work was therefore to experimentally assess the vector competence of sterile males treated with isometamidium for Trypanosoma brucei brucei.
Identification and functional analysis of Cochliomyia hominivorax U6 gene promoters
27884R. Novas, T. Basika, M. E. Williamson, P. Fresia, A. Menchaca and M. J. Scott, Insect Molecular Biology, 2023-03-21 08:32:32.
The New World screwworm, Cochliomyia hominivorax, is an obligate parasite, which is a major pest of livestock. While the sterile insect technique was used very successfully to eradicate C. hominivorax from North and Central America, more cost-effective genetic methods will likely be needed in South America. The recent development of CRISPR/Cas9-based genetic approaches, such as homing gene drive, could provide a very efficient means for the suppression of C. hominivorax populations. One component of a drive system is the guide RNA(s) driven by a U6 gene promoter. Here, we have developed an in vivo assay to evaluate the activity of the promoters from seven C. hominivorax U6 genes. Embryos from the related blowfly Lucilia cuprina were injected with plasmid DNA containing a U6-promoter-guide RNA construct and a source of Cas9, either protein or plasmid DNA. Activity was assessed by the number of site-specific mutations in the targeted gene in hatched larvae. One promoter, Chom U6_b, showed the highest activity. These U6 gene promoters could be used to build CRISPR/Cas9-based genetic systems for the control of C. hominivorax.
The sex pheromone heptacosane enhances the mating competitiveness of sterile Aedes aegypti males
24861L.-M. Wang, N. Li, M. Zhang, Q. Tang, H.-Z. Lu, Q.-Y. Zhou, J.-X. Niu, L. Xiao, Z.-Y. Peng, C. Zhang, M. Liu, D.-Q. Wang and S.-Q. Deng, Parasites and Vectors, 16:102. 2023-03-15 15:04:09.
Aedes aegypti is a vector that transmits various viral diseases, including dengue and Zika. The radiation-based sterile insect technique (SIT) has a limited effect on mosquito control because of the difficulty in irradiating males without reducing their mating competitiveness. In this study, the insect sex pheromone heptacosane was applied to Ae. aegypti males to investigate whether it could enhance the mating competitiveness of irradiated males. Heptacosane was smeared on the abdomens of Ae. aegypti males that were allowed to mate with untreated virgin females. The insemination rate was used to assess the attractiveness of heptacosane‑treated males to females. The pupae were irradiated with different doses of X‑rays and γ‑rays, and the emergence, survival time, egg number, and hatch rate were detected to find the optimal dose of X‑ray and γ‑ray radiation. The males irradiated at the optimal dose were smeared with heptacosane, released in different ratios with untreated males, and mated with females. The effect of heptacosane on the mating competitiveness of irradiated mosquitoes was then evaluated by the hatch rate, induced sterility, and mating competitiveness index. Results Applying heptacosane to Ae. aegypti males significantly increased the insemination rate of females by 20%. Pupal radiation did not affect egg number but significantly reduced survival time and hatch rate. The emergence of the pupae was not affected by X‑ray radiation but was affected by γ‑ray radiation. Pupae exposed to 60 Gy X‑rays and 40 Gy γ‑rays were selected for subsequent experiments. After 60 Gy X‑ray irradiation or 40 Gy γ‑ray irradiation, the average hatch rate was less than 0.1%, and the average survival time was more than 15 days. Moreover, at the same release ratio, the hatch rate of the irradiated group perfumed with heptacosane was lower than that of the group without heptacosane. Conversely, the male sterility and male mating competitiveness index were significantly increased due to the use of heptacosane.
CRISPR-based genetic control strategies for insect pests
24978Y. Yan, R. A. Aumann, I. Hacker and M. F. Schetelig, Journal of Integrative Agriculture, 22:651-668. 2023-03-11 07:53:08.
Genetic control strategies such as the sterile insect technique have successfully fought insect pests worldwide. The CRISPR (clustered regularly interspaced short palindromic repeats) technology, together with high-quality genomic resources obtained in more and more species, greatly facilitates the development of novel genetic control insect strains that can be used in area-wide and species-specific pest control programs. Here, we review the research progress towards state-of-art CRISPR-based genetic control strategies, including gene drive, sex ratio distortion, CRISPR-engineered genetic sexing strains, and precision-guided sterile insect technique. These strategies' working mechanisms, potential resistance development mechanisms, and regulations are illustrated and discussed. In addition, recent developments such as stacked and conditional systems are introduced. We envision that the advances in genetic technology will continue to be one of the driving forces for developing the next generation of pest control strategies.
Galapagos to receive male mosquitoes for vector control in Ecuador
24835A. R. Martin, Prensa Latina, 2023-03-07 08:39:27.
The Galapagos Islands will receive 100,000 sterile male mosquitoes as part of a new vector control strategy in Ecuador, the Center for Research in Infectious and Vector Diseases (CIREV) announced. Reducing the Aedes aegypti in Ecuador is in charge of the National Institute for Public Health Research (INSPI), and will start off the experimental phase coming Friday, March 10. The research, which started in 2017, is co-financed by the Technical Cooperation Program of the International Atomic Energy Agency
Genomic and cytogenetic analysis of the Ceratitis capitata temperature-sensitive lethal region
25470G. Sollazzo, G. Gouvi, K. Nikolouli, R. A. Aumann, H. Djambazian, M. A. Whitehead, P. Berube, S.-H. Chen, G. Tsiamis, A. C. Darby, J. Ragoussis, M. F. Schetelig and K. Bourtzis, G3-Genes Genomes Genetics, 13. 2023-03-03 08:40:56.
Genetic sexing strains (GSS) are an important tool in support of sterile insect technique (SIT) applications against insect pests and disease vectors. The yet unknown temperature-sensitive lethal (tsl) gene and the recently identified white pupae (wp) gene have been used as selectable markers in the most successful GSS developed so far, the Ceratitis capitata (medfly) VIENNA 8 GSS. The molecular identification of the tsl gene may open the way for its use as a marker for the development of GSS in other insect pests and disease vectors of SIT importance. Prior studies have already shown that the tsl gene is located on the right arm of chromosome 5, between the wp and Zw loci (tsl genomic region). In the present study, we used genomic, transcriptomic, bioinformatic, and cytogenetic approaches to characterize and analyze this genomic region in wild-type and tsl mutant medfly strains. Our results suggested the presence of 561 genes, with 322 of them carrying SNPs and/or insertion–deletion (indel) mutations in the tsl genomic region. Furthermore, comparative transcriptomic analysis indicated the presence of 32 differentially expressed genes, and bioinformatic analysis revealed the presence of 33 orthologs with a described heat-sensitive phenotype of Drosophila melanogaster in this region. These data can be used in functional genetic studies to identify the tsl gene(s) and the causal mutation(s) responsible for the temperature-sensitive lethal phenotype in medfly, and potentially additional genes causing a similar phenotype.
Satellite Rearing of Aedes Mosquito Eggs: Synchronized Empirical Test of a Novel Mass Rearing Model
24981K. L. Dobson, K. Blore, J. A. Henke, K. Y. Hung, T. Morgan, T. Posey, S. Sun, O. Sypes, N. P. Tremblay and S. L. Dobson, J Am Mosq Control Assoc, 39:12-17. 2023-03-01 09:41:35.
Mosquito suppression strategies based on "rear and release" of male mosquitoes are attracting renewed interest from governments, municipalities, and private businesses. These include irradiation-based sterile insect technique, Wolbachia-based technologies, and genetic modification. Each of these approaches requires the mass rearing and release of adult male mosquitoes, which typically is accomplished via a rearing facility near the release site. Although some release programs have relied on centralized rearing and shipment of adult males, adult male mosquitoes are relatively fragile, and their fitness can be diminished by temperature fluctuations, humidity, nutritional deficiencies, and other stresses that occur during shipment. Furthermore, expensive, expedited shipment is typically used to maximize the amount of adult lifetime in the field following the release. In contrast, Aedes aegypti and Ae. albopictus eggs can be desiccated and stored for long periods. They are small, and many millions of eggs can be shipped without specialized environmental conditions and using less expensive means. Here we examine a model in which mosquito eggs are centrally produced and then mailed to satellite rearing facilities. As a control, a replicate set of eggs was reared at the factory of origin. At each of the rearing sites, cloud-based software was used to track and compare rearing at the different locations. The results demonstrate similar rearing outcomes (i.e., egg hatch, immature development, and number of adult males) at each of the different sites for both species. We discuss the outcome in relation to downstream applications and potential future studies.
Development of transgenic corn planthopper Peregrinus maidis that express the tetracycline transactivator
27707A. A. Patil, W. Klobasa, D. Espinoza-Rivera, O. Baars, M. D. Lorenzen and M. J. Scott, Insect Molecular Biology, 32:363-375. 2023-02-24 09:39:46.
Abstract The corn planthopper, Peregrinus maidis, is a vector of several maize viruses and is consequently a significant agricultural pest in many tropical and subtropical regions. As P. maidis has developed resistance to insecticides, the aim of this study was to develop transgenic P. maidis strains that could be used for future genetic biocontrol programs. To facilitate the identification of transgenic P. maidis, we isolated and characterized the promoters for the P. maidis ubiquitin-like and profilin genes. Transient expression assays with P. maidis embryos showed that both promoters were active. Transgenic lines were established using piggyBac vectors and fluorescent protein marker genes. The lines carried an auto-regulated tetracycline transactivator (tTA) gene, which has been widely used to establish conditional lethal strains in other insect species. The transgenic lines showed low levels of tTA expression but were viable on diet with or without doxycycline, which inhibits the binding of tTA to DNA. We discuss possible modifications to the tTA overexpression system that could lead to the successful development of conditional lethal strains. To our knowledge, this is the first report of a transgenic Hemiptera. The approach we have taken could potentially be applied to other Hemiptera and, for P. maidis, the technology will facilitate future functional genomics studies.
Will new genetic engineering tech finally eliminate malaria?
24747Anonymous, Business Daily, 2023-02-20 19:03:20.
Richard Mukabana, a senior research and policy analyst at African Institute for Development Policy, says the technology which employs the principle of sending a thief to catch a thief may yet prove the most effective. “It is only a mosquito that knows where another mosquito is and it’s easier for it to search for others and kill them through suppression,” says Prof Mukabana. In gene drive technologies, an artificial gene is introduced into the malaria-transmitting mosquito population. This then disrupts reproduction by either distorting sex chromosome inheritance such that most offspring are males, or by knocking out female fertility genes such that they no longer lay eggs. Experts argue that the current technology used in fighting malaria, which comprises vector control and drug therapy has not been sufficiently adequate to eliminate the disease on the continent, hence the need to embrace new technologies.
From the Lab to the Field: Long-Distance Transport of Sterile Aedes Mosquitoes
24750H. Maïga, M. T. Bakhoum, W. Mamai, G. Diouf, N. S. Bimbilé Somda, T. Wallner, C. Martina, S. S. Kotla, O. B. Masso, H. Yamada, B. B. D. Sow, A. G. Fall and J. Bouyer, Insects, 14. 2023-02-18 19:03:39.
Pilot programs of the sterile insect technique (SIT) against Aedes aegypti may rely on importing significant and consistent numbers of high-quality sterile males from a distant mass rearing factory. As such, long-distance mass transport of sterile males may contribute to meet this requirement if their survival and quality are not compromised. This study therefore aimed to develop and assess a novel method for long-distance shipments of sterile male mosquitoes from the laboratory to the field. Different types of mosquito compaction boxes in addition to a simulation of the transport of marked and unmarked sterile males were assessed in terms of survival rates/recovery rates, flight ability and morphological damage to the mosquitoes. The novel mass transport protocol allowed long-distance shipments of sterile male mosquitoes for up to four days with a nonsignificant impact on survival (>90% for 48 h of transport and between 50 and 70% for 96 h depending on the type of mosquito compaction box), flight ability, and damage. In addition, a one-day recovery period for transported mosquitoes post-transport increased the escaping ability of sterile males by more than 20%. This novel system for the long-distance mass transport of mosquitoes may therefore be used to ship sterile males worldwide for journeys of two to four days. This study demonstrated that the protocol can be used for the standard mass transport of marked or unmarked chilled Aedes mosquitoes required for the SIT or other related genetic control programs.
White-Eyed Fruit Flies: How Improvements in Gene Editing Could Aid in Pest Managemen
24752C. Bernhardt, Entomology Today, 2023-02-17 19:07:21.
The SIT involves scientists raising the target fruit fly species in the lab, sterilizing the flies by exposing them to a certain amount of radiation while they are still pupae, and releasing large amounts of the newly sterile flies into nature. When the released, sterile flies mate with wild flies, they produce infertile eggs that never hatch and, over time, this reduces—and hopefully eliminates—the population of flies. “But research shows that if you only release sterile males—instead of sterile males and females at the same time—you can more efficiently accomplish management,” says Daniel Paulo, PhD, a researcher in the Department of Plant and Environmental Protection Sciences at the University of Hawaiʻi at Mānoa. Male flies mate more often than females and don’t damage fruits in the field because they don’t lay eggs. Male-focused SIT programs also guarantee sterile males are using their energy to mate with wild-type females, not with females who were also sterilized. So, scientists target male flies with sterilization efforts by using a classic genetic method called genetic sexing, which helps create sex-specific, visible physical characteristics or markers (called phenotypes) among fruit flies. These phenotypes make it possible for scientists to tell the two sexes apart more easily and parse the males and females before sterilizing. A colony of such flies is called genetic sexing strain (GSS). A GSS requires a phenotype scientists can create by inducing a genetic change, called a mutation, that leads to a visible characteristic. Next, they link the normal, non-mutated visual marker to the male sex.
When less is more: accounting for overcompensation in mosquito SIT projects
24717J. Bouyer, Trends in Parasitology, 2023-02-08 10:14:35.
Compensation and overcompensation under field conditions are confirmed in Aedes mosquitoes recently by Evans et al.: equal or increased densities of emerging adults may thus result from reduced larval densities. Here the consequences when applying the sterile insect technique and provide recommendations to avoid counterproductive effects are discussed.
How CRISPR could help save crops from devastation caused by pests
24675E. F. Merchant, MIT Technology Review, 2023-02-02 10:23:26.
Researchers are now looking to add cutting-edge technology to California’s anti-Pierce’s arsenal, by changing the genome of the glassy-winged sharpshooter so that it can no longer spread the bacterium. Such a solution is possible thanks to CRISPR gene-editing technology, which has made modifying the genes of any organism increasingly simple. The technique has been used in experiments in cancer immunotherapy, apple breeding, and—controversially—human embryos. Now a growing number of researchers are applying it to agricultural pests, aiming to control a range of insects that together destroy about 40% of global crop production each year. If successful, these efforts could reduce reliance on insecticides and provide an alternative to genetic modifications to crops. For now, these gene-edited insects are shut away in labs across the globe, but that is poised to change. This year, a US company expects to start greenhouse tests in conjunction with the US Department of Agriculture (USDA) of fruit-damaging insects made sterile using CRISPR. At the same time, scientists at government and private institutions are beginning to learn more about pest genetics and to make edits in more species.
Imperial startup Biocentis to develop genetic tech to control harmful insects
24673D. Silverman, Imperial College London, 2023-02-01 10:17:53.
The Imperial startup was founded in 2022 by Imperial researchers in partnership with technology-focused investment group Neurone to create a more effective and sustainable alternative to pesticides. While insects play an essential role in the global ecosystem, among the planet’s millions of insect species are some that spread devastating human diseases such as Dengue Fever and Zika virus, exacerbate food insecurity by spoiling up to 25% of crops, and reduce biodiversity by invading new ecosystems to the detriment of local species. At present, these harmful insect populations are controlled primarily with pesticides. But the growth of pesticide resistance is prompting control programmes to increase the dose and frequency of the toxic chemicals, causing increasing harm to bees and other non-target species.
Joint FAO/IAEA Coordinated Research Project on Mosquito Handling, Transport, Release and Male Trapping Methods in Support of SIT Application to Control Mosquitoes
24566M. Gómez, B. J. Johnson, H. C. Bossin and R. Argilés-Herrero, Insects, 14. 2023-01-19 08:14:17.
The research carried out in the framework of this CRP generated key achievements in areas relevant to the SIT application to control mosquitoes. Among these outcomes, particular mentions must be given to the following: (1) Novel and efficient self-marking techniques were established to improve our understanding of male movement, competitiveness, survival, and potential interaction with closely related species post-release [7,8]. As the next step, these new marking systems will be upscaled and validated under operational conditions in SIT field projects targeting the Aedes species. (2) One of the techniques evaluated included the novel large-scale marking of male mosquitoes via administration of Rhodamine B via sugar feeding. The mentioned technique brings the advantage of marking all of the tissues of the mosquitoes, including sperm and seminal fluid, such that the mark can be retrieved and identified in mated females. Thus, the use of Rhodamine B enables researchers to estimate the sexual competitiveness of sterile male mosquitoes under field conditions [9,10].
Effects of gamma radiation on the vector competence of Aedes aegypti (diptera: Culicidae) to transmit Zika virus
24462E. B. da Silva, C. M. de Mendonça, D. R. D. Guedes, M. H. S. Paiva, J. d. A. Mendonça, E. S. F. Dias, S. G. L. Florêncio, A. Amaral, A. M. Netto, C. F. J. A. Lopes and M. A. V. de Melo-Santos, Acta Tropica, 239:106831. 2023-01-11 08:27:34.
One of the limitations of the Sterile Insect Technique (SIT), conventionally performed by ionizing radiation, regards separating males from females, which is not 100% effective. Some irradiated females may be released together with males in the field at SIT. The present study aimed to evaluate the influence of ionizing radiation on the ability of Aedes aegypti mosquitoes to transmit the Zika virus after exposing female pupae to a 40 Gy of gamma radiation. The results suggest that the genetic damage induced by exposure of females to this dose level promotes their total sterility, but it does not influence their vector competence. However, our data point out that ionizing radiation may decrease the proportion of infective mosquitoes.
Sterility of Aedes albopictus by X-ray Irradiation as an Alternative to γ-ray Irradiation for the Sterile Insect Technique
24424L.-M. Wang, N. Li, C.-P. Ren, Z.-Y. Peng, H.-Z. Lu, D. Li, X.-Y. Wu, Z.-X. Zhou, J.-Y. Deng, Z.-H. Zheng, R.-Q. Wang, Y.-N. Du, D.-Q. Wang and S.-Q. Deng, Pathogens, 12. 2023-01-06 10:18:19.
The mosquito Aedes albopictus can transmit various arboviral diseases, posing a severe threat to human health. As an environmentally friendly method, sterile insect technology (SIT) is considered an alternative to traditional methods such as chemical pesticides to control Ae. albopictus. In SIT, the sterility of male mosquitoes can be achieved by γ-ray or X-ray radiation. Compared with γ-rays, X-rays are easier to obtain, cheaper, and less harmful. However, there is a lack of comparative assessment of these two types of radiation for SIT under the same controlled conditions. Here, we compared the effects of X-ray and γ-ray radiation on the sterility of Ae. albopictus males under laboratory-controlled conditions. Neither type of radiation affected the number of eggs but significantly reduced the survival time and hatch rate. The same dose of γ-rays caused a higher sterility effect on males than X-rays but had a more significant impact on survival. However, X-rays could achieve the same sterility effect as γ-rays by increasing the radiation dose. For example, X-rays of 60 Gy induced 99% sterility, similar to γ-rays of 40 Gy. In the test of male mating competitiveness, the induced sterility and the male mating competitiveness index were also identical at the same release ratio (sterile males/fertile males). At a release ratio of 7:1, nearly 80% of eggs failed to hatch. Sterile males produced by X-ray and γ-ray radiation had similar male competitiveness in competition with field males. In conclusion, a higher dose of X-rays is required to achieve the same sterility effect, compared to γ-rays. When γ-rays are not readily available, high-dose X-rays can be used instead. This study provides data supporting the selection of more suitable radiation for the field release of sterile male mosquitoes.
Biotech company released 2.4 billions GM Mosquitoes in two parts of the U.S
24346C. Victorial, NEWSBREAK, 2022-12-27 16:20:57.
Due to the high death rate that mosquitoes have inflicted, The Environmental Protection Agency (EPA) has approved the release of 2.4 billion genetically modified mosquitoes in selected regions of California and Florida. These modified mosquitoes were created by a biotechnology company called Oxitec. The technology creates non-biting Aedes aegypti, which are common invasive types of mosquito. The males are engineered to only produce other male offspring. Oxitec states that the process will greatly reduce the number mosquitoes, as female mosquitoes are expected to die, while males will reproduce and spread the self-limiting gene to the next upcoming generation. The goal is to eventually decrease the population of all mosquitos to regulated state.
Gene drive designs for efficient and localisable population suppression using Y-linked editors
24339R. Geci, K. Willis and A. Burt, PLOS Genetics, 18:e1010550. 2022-12-27 08:45:03.
Author summary Some pest populations can be successfully controlled by the inundative release of sterile males, but this approach is not practicable when the target population is large or the species difficult to rear. Computer modelling has previously demonstrated that releasing males with a genomic editor on their Y chromosome that kills or sterilises female descendants could be much more efficient, particularly if combined with a sex ratio distorter. Here we extend this work to show that Y-linked editors can also be used in even more efficient gene drive designs that would spread over successive generations beyond the region of release. Such spread could nonetheless be controlled by exploiting relatively small pre-existing differences in gene frequency between populations to restrict the spread and impact of the constructs, if desired. The proposed design does not require high rates of recombinational repair of DNA breaks or expression off the Y chromosome during meiosis, potentially expanding the range of species in which such low release rate control is possible. Y-linked editors may therefore form the basis of a highly flexible set of genetic strategies for population control.
Survival-Larval Density Relationships in the Field and Their Implications for Control of Container-Dwelling Aedes Mosquitoes
24714K. G. Evans, Z. R. Neale, B. Holly, C. C. Canizela and S. A. Juliano, Insects, 14. 2022-12-23 10:10:37.
Population density can affect survival, growth, development time, and adult size and fecundity, which are collectively known as density-dependent effects. Container Aedes larvae often attain high densities in nature, and those densities may be reduced when larval control is applied. We tested the hypothesis that density-dependent effects on survival are common and strong in nature and could result in maximal adult production at intermediate densities for Aedes aegypti, Aedes albopictus, and Aedes triseriatus. We surveyed naturally occurring densities in field containers, then introduced larvae at a similar range of densities, and censused the containers for survivors. We analyzed the survival-density relationships by nonlinear regressions, which showed that survival-density relationships vary among seasons, sites, and species. For each Aedes species, some sites and times yielded predictions that larval density reduction would yield the same (compensation), or more (overcompensation), adults than no larval density reduction. Thus, larval control targeting these Aedes species cannot always be assumed to yield a reduction in the number of adult mosquitoes. We suggest that mosquito control targeting larvae may be made more effective by: Imposing maximum mortality; targeting populations when larval abundances are low; and knowing the shape of the survival-density response of the target population.
Mating Competitiveness of Irradiated Lobesia botrana (Lepidoptera: Tortricidae) in Male-Only and Both Sex Release Strategies under Laboratory Cage Conditions
24324G. Saour, A. Hashem and I. Jassem, Insects, 14. 2022-12-23 09:03:18.
This laboratory study explored the concept of whether irradiated male-only releases are more or equally efficient as releases of both irradiated males and females in the context of using the sterile insect technique/inherited sterility (SIT/IS) for the management of the European grapevine moth Lobesia botrana. The current study examined the mating competitiveness of 150-Gy-treated L. botrana male and female moths or 150-Gy-treated male moths only, with untreated moths in laboratory cages. Our results showed that the release of both sexes significantly increased the competitiveness value (C) and the biological efficiency index (BE) as compared with male-only release, and this was independent of the male to untreated male ratio. Moreover, a single release of 150-Gy-treated and untreated males and females at a 1:1:10:10 ratio (untreated male:untreated female: treated male:treated female) significantly reduced egg hatch, and the number of first-generation offspring (F1) was small. The emergence of F2-moths per untreated F1 male and female moth was low, but these undesired fertile moths should be eliminated in order to achieve effective control. The results presented herein provide useful information on the impact of 150-Gy-treated male-only, versus releases of both treated males and females on untreated moths, which is essential to managing L. botrana populations with SIT/IS.
Assessing the efficacy of male Wolbachia-infected mosquito deployments to reduce dengue incidence in Singapore: study protocol for a cluster-randomized controlled trial
24268J. Ong, S. H. Ho, S. X. H. Soh, Y. Wong, Y. Ng, K. Vasquez, Y. L. Lai, Y. X. Setoh, C. S. Chong, V. Lee, J. C. C. Wong, C. H. Tan, S. Sim, L. C. Ng and J. T. Lim, Trials, 23:1023. 2022-12-17 13:57:59.
The study is designed as a parallel, two-arm, non-blinded cluster-randomized (CR) controlled trial to be conducted in high-rise public housing estates in Singapore, an equatorial city-state. The aim is to determine whether large-scale deployment of male Wolbachia-infected Ae. aegypti mosquitoes can significantly reduce dengue incidence in intervention clusters. We will use the CR design, with the study area comprising 15 clusters with a total area of 10.9 km(2), covering approximately 722,204 residents in 1713 apartment blocks. Eight clusters will be randomly selected to receive the intervention, while the other seven will serve as non-intervention clusters. Intervention efficacy will be estimated through two primary endpoints:
East Maui project hopes mosquito v. mosquito mating battle will save endangered birds
24173K. Cerizo, MAUINOW, 2022-12-11 11:03:34.
Good news in the fight against vector-borne diseases
24175K. Magori, 2022-12-09 11:07:13.
At the turn of the century, several research groups attempted to apply modern genetic methodologies to achieve similar outcomes without the need for irradiation and the resulting fitness costs. Luke Alphey and his colleagues at Oxford University developed a dominant lethal genetic system for autocidal control in the Mediterranean fruitfly, where a transactivator causes lethality in the early developmental stages of heterozygous insects unless repressed by tetracycline. The company he funded (Oxitec Limited) successfully adapted this system in several agriculturally important pest species, as well as in Aedes aegypti and other mosquitoes. (Full disclosure: I worked at Oxitec Limited in 2007, but own no shares or have any other conflict of interest with them). While the first generation of these mosquitoes proved to successfully reduce wild-type mosquito populations, they required labor-intensive separation of male and female mosquitoes before release in close proximity. While this ensured that only non-biting male mosquitoes are released, it also limited the scalability of this approach.
A mass rearing cost calculator for the control of Culex quinquefasciatus in Hawaiʻi using the incompatible insect technique
24332A. E. Vorsino and Z. Xi, Parasites and Vectors, 15:453. 2022-12-05 08:32:07.
Hawaiʻi’s native forest avifauna is experiencing drastic declines due to climate change-induced increases in temperature encroaching on their upper-elevation montane rainforest refugia. Higher temperatures support greater avian malaria infection rates due to greater densities of its primary vector, the southern house mosquito Culex quinquefasciatus, and enhance development of the avian malaria parasite Plasmodium relictum. Here we propose the use of the incompatible insect technique (IIT) or the combined IIT/sterile insect technique (SIT) for the landscape-scale (i.e., area-wide) control of Cx. quinquefasciatus, and have developed a calculator to estimate the costs of IIT and IIT/SIT applications at various sites in Hawaiʻi.
Oxitec’s mosquitoes are getting “friendly” with California
24109L. Patrick, The Sun Gazette, 2022-12-01 09:34:07.
Biotech company Oxitec is buzzing around Visalia, with the hopes of releasing their genetically engineered mosquitoes in Tulare County. Oxitec has one more hurdle to jump over in order to release their “friendly” Aedes aegypti mosquitoes in Tulare County, and that’s to gain the approval of the California Department of Pesticide Regulation (DPR). Though their attempts to release their GE mosquitoes in California have been met with both supportive and hesitant reactions from different state agencies and environmental groups, Oxitec’s Dr. Kevin Gorman said the technology has been researched and reviewed with “much scrutiny,” despite claims that the mosquitoes are ineffective or hazardous. “We have a biological approach to managing pest insects, and the biological approach is a mating-based technology. It’s very targeted, it only affects the species that [they’re] mating with,” Gorman said. “Not only is it environmentally safe, it’s effective.” The male GE mosquitoes from Oxitec have been engineered with a self-limiting gene, and this gene infects wild female mosquitoes to prevent them from reproducing female offspring. This leaves only male mosquitoes in the gene pool, according to Gorman. Female mosquitoes are targeted since they are the only ones that bite, and therefore capable of transmitting diseases. The engineered males will only mate with Aedes aegypti females, and do not leave an environmental footprint, according to Gorman. The release of these mosquitoes is supposed to reduce the natural population of the invasive mosquito, which are known to carry diseases such as dengue, chikungunya, Zika, yellow fever and others.
Does severe hypoxia during irradiation of Aedes aegypti pupae improve sterile male performance?
24069D. A. Tussey, K. J. Linthicum and D. A. Hahn, Parasites and Vectors, 15:446. 2022-11-28 10:25:24.
The yellow fever mosquito, Aedes aegypti, vectors several pathogens responsible for human diseases. As a result, this mosquito species is a priority for control by mosquito control districts in Florida. With insecticide resistance development becoming a concern, alternative control strategies are needed for Ae. aegypti. Sterile insect technique (SIT) is an increasingly popular option that is being explored as a practical area-wide control method. However, questions about sterile male performance persist. The objectives of this study were to determine the extent to which hypoxia exposure prior to and during irradiation effects the longevity, activity and mating competitiveness of sterile male Ae. aegypti.
Developing radiation-based sterile insect technique (SIT) for controlling Aedes aegypti: identification of a sterilizing dose
24028C. Chen, R. L. Aldridge, S. Gibson, J. Kline, V. Aryaprema, W. Qualls, R.-d. Xue, L. Boardman, K. J. Linthicum and D. A. Hahn, Pest Management Science, 2022-11-24 09:37:31.
Abstract Background The sterile insect technique (SIT) is emerging as a tool to supplement traditional pesticide-based control of Aedes aegypti, a prominent mosquito vector of microbes that have increased the global burden of human morbidity and mortality over the past 50?years. SIT relies on rearing, sterilizing, and releasing large numbers of male mosquitoes that will mate with fertile wild females, thus reducing production of offspring from the target population. In this study, we investigated the effects of ionizing radiation (gamma) on male and female survival, longevity, mating behavior, and sterility of Ae. aegypti in a dose-response design. This work is a first step towards developing an operational SIT field suppression program against Ae. aegypti in St. Augustine, Florida, USA. Results Exposing late-stage pupae to 50 Gy of radiation yielded 99% male sterility while maintaining similar survival of pupae to adult emergence, adult longevity, and male mating competitiveness compared to unirradiated males. Females were completely sterilized at 30 Gy, and when females were dosed with 50 Gy, they had a lower incidence of blood feeding than unirradiated females. Conclusion Our work suggests that an ionizing radiation dose of 50 Gy should be used for future development of operational SIT in our program area because at this dose males are 99% sterile while maintaining mating competitiveness against unirradiated males. Furthermore, females that might be accidentally released with sterile males due to errors in sex sorting are also sterile and less likely to blood feed than unirradiated females at our 50 Gy dose.
Turns Out Fighting Mosquitoes With Mosquitoes Actually Works
24018E. Mullin, Wired, 2022-11-21 08:56:57.
In the Brazilian city of Indaiatuba, an effort is underway to eliminate these pests before they have a chance to spread illness. The weapon: more Aedes aegypti mosquitoes—but ones genetically engineered to kill their own kind. Made by British biotechnology firm Oxitec, the mosquitoes seem to be working. The modified mosquitoes carry a synthetic self-limiting gene that prevents female offspring from surviving. This is important, because only the females bite and transmit disease. In a new study, scientists at the company showed that their engineered insects were able to slash the local population of Aedes aegypti by up to 96 percent over 11 months in the neighborhoods where they were released. “This is an area with high levels of Aedes aegypti, and they periodically have outbreaks of dengue,” says Nathan Rose, head of malaria programs at Oxitec. In fact, this summer the Brazilian Ministry of Health reported that dengue fever was continuing to spread in all five regions of the country. Between January 1 and May 31, Brazil had more than 1.1 million cases—an increase of 198 percent compared to the same period in 2021. In those five months, the disease, which causes high fever, rash, and muscle and joint pain, killed 504 people. For the study, which was conducted in 2018 and 2019, the company chose four densely populated neighborhoods with high levels of Aedes aegypti. In two, scientists released a “dose” of 100 male mosquitoes per resident per week. In the others, they cranked that up to 500.
Calif. Legislature bites back at GE mosquito releases
23866L. Patrick, Sun Gazette, 2022-11-08 10:15:50.
A biotech company created millions of genetically modified mosquitoes, but not in the Jurassic Park sense. The lab grown species could actually lower the population of an invasive mosquito that carries a plethora of diseases on its shoulders.On Nov. 3, several members of the California legislature sent a letter to the Department of Pesticide Regulation (DPR) asking it to delay the release of millions of genetically engineered (GE) mosquitoes in Tulare County by Oxitec, a British biotech company, in the interest of further regulatory review. The GE mosquitoes are meant to lower the population of Aedes aegypti, an invasive mosquito that has been plaguing communities in the county for the last few years. However, members of the legislature are pushing for the DPR to resist the GE mosquitoes because of unforeseen effects they might have on people and the environment. This would be the first experimental release of of the non-biting mosquitoes, which OxiTec calls “friendly mosquitoes,” in Tulare County. Though the U.S. Environmental Protection Agency approved the release of the mosquitoes on March 7, the agency has been awaiting approval from DPR for several months, even after a 15-month scientific evaluation process and a 15-day public comment period that ended on April 19.
A sterile insect technique pilot trial on Captiva Island: defining mosquito population parameters for sterile male releases using mark–release–recapture
23818D. O. Carvalho, R. Morreale, S. Stenhouse, D. A. Hahn, M. Gomez, A. Lloyd and D. Hoel, Parasites and Vectors, 15:405. 2022-11-01 10:41:32.
The sterile insect technique (SIT), which involves area-wide inundative releases of sterile insects to suppress the reproduction of a target species, has proven to be an effective pest control method. The technique demands the continuous release of sterilized insects in quantities thatThe sterile insect technique (SIT), which involves area-wide inundative releases of sterile insects to suppress the reproduction of a target species, has proven to be an effective pest control method. The technique demands the continuous release of sterilized insects in quantities that ensure a high sterile male:wild male ratio for the suppression of the wild population over succeeding generations. Over the course of seven mark-release-recapture studies using single- and multiple-point releases, 190,504 sterile marked males were released, for which the recapture rate was 1.5% over a mean period of 12 days. The mean distance traveled by sterile males of the local strain of Ae. aegypti that has colonized Captiva Island was 201.7 m from the release point, with an observed maximum traveled distance of 404.5 m. The released sterile mosquitoes had a probability of daily survival of 0.67 and an average life expectancy of ~ 2.46 days.s These data together with the population size estimate and sterile:wild ratio provide a solid basis for planning the SIT operational phase which is aimed at mosquito population suppression. ensure a high sterile male:wild male ratio for the suppression of the wild population over succeeding generations.
Genetically modified mosquitoes cut the insect’s number by 96 per cent
23812M. Fauzia, NewScientist, 2022-10-31 09:18:00.
The release of genetically modified male mosquitoes into a city in Brazil temporarily cut the virus-carrying insects by up to 96 per cent. Although not a permanent fix, periodically releasing such mosquitoes could reduce the burden of infections including dengue, malaria and Zika. Kevin Gorman at the biotechnology firm Oxitec in Abingdon, UK, and his colleagues are particularly looking to control dengue. Although usually mild, the infection can be fatal. Already widespread …
Zombie Deer and the Scientists Behind the War on the ‘Man Eater’
24023S. Jones, NC STATE CALS News, 2022-10-24 09:52:07.
In the remote jungles of the Panama-Colombia border, sterile flesh-eating flies fall from the sky in the thousands. Released from retired military planes, they embark on a suicide mission for their species, with the sole purpose of duping their female counterparts into mating with them despite their inability to bear offspring. Before this military-like operation became the norm, the New World Screwworm (Cochliomyia hominivorax or “man-eater”) cost livestock producers millions of dollars every year as a merciless parasite. Without scientific intervention, the screwworm’s life cycle weaves a devastating tale fit for classic horror films of a bygone era. After a successful rendezvous with a male screwworm, the female screwworm spends her time drinking the sweet nectar of the forest. When she’s ready to lay her eggs, she emerges from the forest and into nearby farms and pastures on the hunt for a suitable host. Then she spots it: a blissfully grazing cow who just so happens to have a scratch on its head. She lands in the wound, lays her eggs and waits for another generation of screwworms to do its worst, which doesn’t take long. This devilish pest has completely adapted to a parasitic lifestyle, with its eggs developing in a matter of hours at the precise body temperature of a poor unsuspecting cow. “They develop at 40 degrees Celsius, which is really hot for most insects. Most flies won’t develop well at that temperature. These do, and they’re very quick,” says Max Scott, Professor of Entomology at North Carolina State University’s Department of Entomology and Plant Pathology.
Combating Mosquito-Borne Diseases with CRISPR
23701N. Spahich, The Scientist, 2022-10-11 08:06:34.
Female mosquitoes are some of the deadliest organisms in the world due to their ability to spread infectious diseases through a simple bite. Mosquito-borne diseases such as yellow fever, Zika, Dengue fever, and malaria kill millions of humans every year, and there are limited therapeutics for their prevention and treatment. While in college, Omar Akbari worked as a public service intern testing the local mosquito population for human pathogens and eradicating these insects with chemicals. During this experience, he felt dissatisfied with the insecticide-based method of controlling mosquito population and wanted to find a better way to tackle the problem of mosquito-borne disease spread. With a multidisciplinary team in his laboratory at the University of California, San Diego, he now develops tools through genetic engineering techniques such as CRISPR to solve the world’s insect control problems.
Quality control traceability during the packing and release process of Ceratitis capitata for sterile insect technique
23621Y. Contreras-Navarro, H. Luis-Alvarez, G. García-Coapio, R. Hernández, S. Flores and P. Montoya, Journal of Applied Entomology, 2022-09-13 14:29:43.
Abstract In programmes applying the sterile insect technique (SIT), the quality of insects deployed in the field determines the success in preventing, suppressing, containing or eradicating the pest population. In the fruit fly emergence and release facility (ERF) of the Moscamed Program in Mexico, irradiated pupae of Ceratitis capitata are packed in Mexico-type towers, and key adult quality parameters, such as emergence, fliers and survival, are determined throughout the packing, handling and release process. However, different methodologies are used to estimate the percentage of fliers in the different stages of the process, raising doubts of whether observed differences are due to the effect of each stage or to the methodology used. With this in mind, we developed an alternative called ?Adult Flier device? (=AF-device) to evaluate the adult flier parameter following a critical evaluation path of five steps: (1) upon arrival at ERF, (2) post-packing, (3) post-holding, (4) post-chilling and (5) post-release, where adult fliers and survival under stress were evaluated. We also compared the current methodologies for the estimation of ?absolute fliers? available in different operating manuals. Our results suggest that the AF-device allows reliable traceability of sterile insect quality parameters throughout the packing and release process, since no significant differences were observed with the control treatments. In the chilling stage, the five methodologies tested were equivalent, but the AF-device was less time-consuming and required less manpower and biological material than the other methodological options. Our results demonstrate that the use of the AF-device can be a feasible, versatile, innovative and efficient alternative to evaluate quality control parameters throughout the process of packing and releasing sterile insects, providing reliable results in a timely manner with less hand labour using minimal biological material.
Fact Check: Bill Gates’ genetically modified mosquitoes are responsible for mosquito-borne viruses in Florida and are part of the next planned pandemic.
23542A. Williams, The Paradise, 2022-09-09 06:00:08.
The genetically modified mosquitoes in Florida are part of a project by Oxitec that Bill Gates did not fund. The virus reported in Florida is the West Nile virus, which has had reported cases in most U.S. states since 1999, with lower cases in 2022 than in previous years. The virus has no correlation to the release of the mosquitoes by Oxitec, and no reports have mentioned they have caused harm. The belief that pandemics are planned by governmental or global business is a known conspiracy and unsubstantiated. Therefore, this claim has been marked as false.
Modified mosquito releases to fight dengue fever, chikungunya or yellow fever
23555Sewell, Tammy, OICANADIAN, 2022-09-05 14:35:46.
To date, only one technique based on genetically modified mosquitoes has been developed at an operational level, it is the RIDL technique (release of insects carrying a dominant lethal gene, or release of insects carrying a dominant lethality gene). Male mosquitoes which, unlike females, do not bite, are genetically modified. Their offspring die before reaching adulthood. This technique has received authorization from the US Environmental Protection Agency. Last spring, the private company Oxitec began a trial in Florida consisting in disseminating mosquito eggs Aedes aegypti (known to carry many viruses such as dengue fever, yellow fever, chikungunya and Zika) genetically modified in nature for three months.
Life-history traits of a fluorescent Anopheles arabiensis genetic sexing strain introgressed into South African genomic background
23550N. L. Ntoyi, T. Mashatola, J. Bouyer, C. Kraupa, H. Maiga, W. Mamai, N. S. Bimbile-Somda, T. Wallner, D. O. Carvalho, G. Munhenga and H. Yamada, Malaria Journal, 21:12. 2022-09-05 06:11:50.
Background South Africa has set a mandate to eliminate local malaria transmission by 2023. In pursuit of this objective a Sterile Insect Technique programme targeting the main vector Anopheles arabiensis is currently under development. Significant progress has been made towards operationalizing the technology. However, one of the main limitations being faced is the absence of an efficient genetic sexing system. This study is an assessment of an An. arabiensis (AY-2) strain carrying the full Y chromosome from Anopheles gambiae, including a transgenic red fluorescent marker, being introgressed into a South African genetic background as a potential tool for a reliable sexing system. Methods Adult, virgin males from the An. arabiensis AY-2 strain were outcrossed to virgin females from the South African, Kwazulu-Natal An. arabiensis (KWAG strain) over three generations. Anopheles arabiensis AY-2 fluorescent males were sorted as first instar larvae (L1) using the Complex Object Parametric Analyzer and Sorter (COPAS) and later screened as pupae to verify the sex. Life history traits of the novel hybrid KWAG-AY2 strain were compared to the original fluorescent AY-2 strain, the South African wild-type KWAG strain and a standard laboratory An. arabiensis (Dongola reference strain). Results The genetic stability of the sex-linked fluorescent marker and the integrity and high level of sexing efficiency of the system were confirmed. No recombination events in respect to the fluorescent marker were detected over three rounds of introgression crosses. KWAG-AY2 had higher hatch rates and survival of L1 to pupae and L1 to adult than the founding strains. AY-2 showed faster development time of immature stages and larger adult body size, but lower larval survival rates. Adult KWAG males had significantly higher survival rates. There was no significant difference between the strains in fecundity and proportion of males. KWAG-AY2 males performed better than reference strains in flight ability tests. Conclusion The life history traits of KWAG-AY2, its rearing efficiency under laboratory conditions, the preservation of the sex-linked fluorescence and perfect sexing efficiency after three rounds of introgression crosses, indicate that it has potential for mass rearing. The potential risks and benefits associated to the use of this strain within the Sterile Insect Technique programme in South Africa are discussed.
Oregon State University professor releases destructive moths, wasps into orchards
23522E. Francovich, statesman journal, 2022-09-04 05:20:27.
Each week for the past three months Christopher Adams, a professor at Oregon State University, has released upward of 4,000 codling moths into the Columbia Gorge’s fertile orchards. The drab, half-inch nonnative insects don’t look like much, but when they lay their larvae inside apples, pears, walnuts or other crops, they wreak havoc. According to one 2018 analysis, they cost Washington apple growers more than half-a-billion dollars in damages. And that’s exactly why Adams has released the moths. No, he’s not an agroterrorist. Each moth he’s let into the wild has been sterilized. “These sterilized male and females fly around and mate with any wild (moths),” Adams says. “Because they are sterilized you don’t get any offspring.” Adams is an assistant professor of tree fruit bugology at Oregon State University’s Hood River extension
A confinable female-lethal population suppression system in the malaria vector, Anopheles gambiae
23500A. L. Smidler, J. J. Pai, R. A. Apte, H. M. Sánchez C, R. M. Corder, E. J. Gutiérrez, N. Thakre, I. Antoshechkin, J. M. Marshall and O. S. Akbari, bioRxiv, 2022.08.30.505861. 2022-08-30 19:10:47.
Malaria is among the world’s deadliest diseases, predominantly affecting sub-Saharan Africa, and killing over half a million people annually. Controlling the principal vector, the mosquito Anopheles gambiae, as well as other anophelines, is among the most effective methods to control disease spread. Here we develop an innovative genetic population suppression system termed Ifegenia (Inherited Female Elimination by Genetically Encoded Nucleases to Interrupt Alleles) in this deadly vector. In this bicomponent CRISPR-based approach, we disrupt a female-essential gene, femaleless (fle), demonstrating complete genetic sexing via heritable daughter gynecide. Moreover, we show that Ifegenia males remain reproductively viable, and can load both fle mutations and CRISPR machinery to induce fle mutations in subsequent generations, resulting in sustained population suppression. Through modeling, we demonstrate that iterative releases of non-biting Ifegenia males can act as an effective, confinable, controllable, and safe population suppression and elimination system.
Genetic Tools for Integrated Management of Pests on Honeybees in the Tropics
25464M. Pattabhiramaiah, S. Mallikarjunaiah and D. Brueckner, Genetic Methods and Tools for Managing Crop Pests, 2022-08-22 09:48:31.
The Asian honeybee is endemic to Asia where it has been used for honey production and pollination services from time immemorial. They are integral to modern agricultural productivity and to survival and vitality of natural ecosystems. However, recent declines in populations and species diversity threaten both food security and natural habitats. Honeybee colonies are assaulted by numerous pests and pathogens including mites and beetles. Novel, cost-effective pest management practices are desperately needed to preserve colony health. Increased pest pressure levels justify the need for additional control methods. Beekeepers should follow the guidelines of integrated pest management (IPM) as an effective control option that will have a minimum impact on honeybee health. The use of genomic tools and engineering technologies has a great potential for enhancement and sustenance of the health of honeybees. This review focusses on the application of innovative advanced genetic tools such as SIT (sterile insect technique), genome editing, gene drive, RNAi, CRISPR/Cas9-mediated gene editing, and gene pyramiding in honeybee pest management.
CRISPR, an eco-friendly technology, may detect crop pests
23460W. Adam, list23, 2022-08-22 09:16:51.
Drosophila suzukii, an invading insect pest, is a threat to agricultural yields, especially to the production of fruits such as strawberries, cherries, plums, and grapes in western countries. Until now, control measures to stop the spread of D. suzukii have been inadequate. A research published in GEN Biotechnology (Precision Guided Sterile Males Suppress Populations of an Invasive Crop Pest) describes the development of a programmable CRISPR-based technique that might, if implemented at large in the wild, eliminate fertile male D. suzukii, effectively, specifically, and safely controlling this pest population. The team at the University of California, San Diego (UCSD) implemented a temperature-inducible, precision-guided, sterile insect technique (pgSIT), described by the team in an earlier investigation, to breed infertile but fit D. suzukii males with modest shorter lifespans. Through empirical experimentation and mathematical modeling, the researchers demonstrated that repeated release of sterilized males can rapidly and successfully eliminate D. suzukii populations.
Precision Guided Sterile Males Suppress Populations of an Invasive Crop Pest
23453N. P. Kandul, J. Liu, A. Buchman, I. C. Shriner, R. M. Corder, N. Warsinger-Pepe, T. Yang, A. K. Yadav, M. J. Scott, J. M. Marshall and O. S. Akbari, GEN Biotechnology, 1:372-385. 2022-08-18 10:24:32.
The Drosophila suzukii invasion of western countries has created an immense agricultural and economic threat to crop production. Despite many attempts to suppress its population, D. suzukii continues to destroy soft-flesh fruits. Precision guided sterile insect technique (pgSIT) utilizes the accuracy of programmable CRISPR gene targeting to generate sterilized males that can be deployed to suppress populations. Here, we generate pgSIT in D. suzukii and empirically and mathematically demonstrate that sterilized males are fit, competitive, and can eliminate populations of D. suzukii. Altogether, we describe an efficient way to generate sterile D. suzukii for release and safe effective population suppression.
CRISPR-based technology targets global crop pest
23449University of California - San Diego, Phys Org, 2022-08-18 10:05:07.
Applying new CRISPR-based technology to a broad agricultural need, researchers at the University of California San Diego have set their aims on a worldwide pest known to decimate valuable food crops. Nikolay Kandul, Omar Akbari and their colleagues first demonstrated the precision-guided sterile insect technique, or pgSIT, in Drosophila melanogaster, the common fruit fly, in 2019. The technology, later adapted to mosquitoes, uses programmable CRISPR techniques to edit key genes that control sex determination and fertility. Under the new system, pgSIT-developed insect eggs are deployed into a targeted population and only sterile males hatch, resulting in a fertility dead end for that species. Kandul, Akbari and their colleagues have now adapted the technology for use in Drosophila suzukii, an invasive fruit fly (also known as the spotted-wing drosophila) responsible for millions of dollars in crop damage. The advancement is described in the journal GEN Biotechnology.
Effect of Wolbachia Infection and Adult Food on the Sexual Signaling of Males of the Mediterranean Fruit Fly Ceratitis capitata
23487G. A. Kyritsis, P. Koskinioti, K. Bourtzis and N. T. Papadopoulos, Insects, 13. 2022-08-17 07:10:32.
Sexual signaling is a fundamental component of sexual behavior of Ceratitis capitata that highly determines males' mating success. Nutritional status and age are dominant factors known to affect males' signaling performance and define the female decision to accept a male as a sexual partner. Wolbachia pipientis, a widespread endosymbiotic bacterium of insects and other arthropods, exerts several biological effects on its hosts. However, the effects of Wolbachia infection on the sexual behavior of medfly and the interaction between Wolbachia infection and adult food remain unexplored. This study was conducted to determine the effects of Wolbachia on sexual signaling of protein-fed and protein-deprived males. Our findings demonstrate that: (a) Wolbachia infection reduced male sexual signaling rates in both food regimes; (b) the negative effect of Wolbachia infection was more pronounced on protein-fed than protein-deprived males, and it was higher at younger ages, indicating that the bacterium regulates male sexual maturity; (c) Wolbachia infection alters the daily pattern of sexual signaling; and (d) protein deprivation bears significant descent on sexual signaling frequency of the uninfected males, whereas no difference was observed for the Wolbachia-infected males. The impact of our findings on the implementation of Incompatible Insect Technique (IIT) or the combined SIT/IIT towards controlling insect pests is discussed.
Sterility of Cydia pomonella by X ray irradiation as an alternative to gamma radiation for the sterile insect technique
23463J.-H. Zhang, N. Li, H.-Y. Zhao, Y.-Q. Wang, X.-Q. Yang and K.-M. Wu, Bulletin of Entomological Research, 2022-08-06 09:27:59.
The codling moth Cydia pomonella is a major pest of global significance impacting pome fruits and walnuts. It threatens the apple industry in the Loess Plateau and Bohai Bay in China. Sterile insect technique (SIT) could overcome the limitations set by environmentally compatible area-wide integrated pest management (AW-IPM) approaches such as mating disruption and attract-kill that are difficult to suppress in a high-density pest population, as well as the development of insecticide resistance. In this study, we investigated the effects of X-ray irradiation (183, 366, 549 Gy) on the fecundity and fertility of a laboratory strain of C. pomonella, using a newly developed irradiator, to evaluate the possibility of X-rays as a replacement for Cobalt60 (60Co-γ) and the expanded future role of this approach in codling moth control. Results show that the 8th-day is the optimal age for irradiation of male pupae. The fecundity decreased significantly as the dosage of radiation increased. The mating ratio and mating number were not influenced. However, treated females were sub-sterile at a radiation dose of 183 Gy (20.93%), and were almost 100% sterile at a radiation dose of 366 Gy or higher. Although exposure to a radiation dose of 366 Gy resulted in a significant reduction in the mating competitiveness of male moths, our radiation biology results suggest that this new generation of X-ray irradiator has potential applications in SIT programs for future codling moth control.
Robust control strategy by the Sterile Insect Technique for reducing epidemiological risk in presence of vector migration
23331P.-A. Bliman and Y. Dumont, Mathematical Biosciences, 350:108856. 2022-07-28 08:36:35.
The Sterile Insect Technique (SIT) is a promising technique to control mosquitoes, vectors of diseases, like dengue, chikungunya or Zika. However, its application in the field is not easy, and its success hinges upon several constraints, one of them being that the treated area must be sufficiently isolated to limit migration or re-invasion by mosquitoes from the outside. In this manuscript we study the impact of males and (fertile) females migration on SIT. We show that a critical release rate for sterile males exists for every migration level, in the context of continuous or periodic releases. In particular, when (fertile) females migration is sufficiently low, then SIT can be conducted successfully using either open-loop control or closed-loop control (or a combination of both methods) when regular measurements of the wild population are completed. Numerical simulations to illustrate our theoretical results are presented and discussed. Finally, we derive a threshold value for the females migration rate, when viruses are circulating, under which it is possible to lower the epidemiological risk in the treated area, according to the size of the human population.
The Florida Keys Mosquito Control District & Oxitec Announce Launch of Next Phase of Ground-Breaking Project
23093Oxitec, Oxitec, 2022-06-30 07:38:27.
In a continuation of the FKMCD-Oxitec Mosquito Project, Oxitec and FKMCD announced that a new phase of the project (“Pilot D”) will be initiated on or after July 7th, 2022. This phase of the project will examine single-point releases of Oxitec’s male mosquitoes. In March of this year the EPA granted an extension of the Experimental Use Permit (EUP) for the continuation of this pilot project. Following this national-level approval, the Florida Department of Agriculture and Consumer Services (FDACS), reviewed and approved Oxitec’s state-level permit applications. The 2022 project launched with Pilot B during the week of May 9th, with the placement of Oxitec’s just-add-water mosquito boxes on private property of volunteer residents in three release areas, all on Vaca Key. Untreated comparison sites are monitored with mosquito traps on Key Colony Beach and Vaca Key.
Manipulating Insect Sex Determination Pathways for Genetic Pest Management: Opportunities and Challenges
23084A. Siddall, T. Harvey-Samuel, T. Chapman and P. T. Leftwich, Frontiers in Bioengineering and Biotechnology, 10. 2022-06-28 07:14:08.
Sex determination pathways in insects are generally characterised by an upstream primary signal, which is highly variable across species, and that regulates the splicing of a suite of downstream but highly-conserved genes (transformer, doublesex and fruitless). In turn, these downstream genes then regulate the expression of sex-specific characteristics in males and females. Identification of sex determination pathways has and continues to be, a critical component of insect population suppression technologies. For example, “first-generation” transgenic technologies such as fsRIDL (Female-Specific Release of Insects carrying Dominant Lethals) enabled efficient selective removal of females from a target population as a significant improvement on the sterile insect technique (SIT). Second-generation technologies such as CRISPR/Cas9 homing gene drives and precision-guided SIT (pgSIT) have used gene editing technologies to manipulate sex determination genes in vivo. The development of future, third-generation control technologies, such as Y-linked drives, (female to male) sex-reversal, or X-shredding, will require additional knowledge of aspects of sexual development, including a deeper understanding of the nature of primary signals and dosage compensation. This review shows how knowledge of sex determination in target pest species is fundamental to all phases of the development of control technologies.
The AalNix3&4 isoform is required and sufficient to convert Aedes albopictus females into males
23070Y. Zhao, B. Jin, P. Liu, X. Xiao, L. Cai, Z. Xie, L. Kong, T. Liu, W. Yang, Y. Wu, J. Gu, Z. Tu, A. A. James and X.-G. Chen, PLOS Genetics, 18:e1010280. 2022-06-23 08:45:44.
Author summary Nix serves as a conserved male-determining factor in the two most important mosquito arboviral vectors, Ae. aegypti and Ae. albopictus. AaeNix alone can convert Ae. aegypti females into fertile but flightless males. AalNix has four alternative splice isoforms whereas AaeNix has one. Little was known previously about which AalNix isoform(s) serve as the primary signal for sex determination. We cloned the promoter region of AalNix gene and constructed piggybac-based AalNix overexpression constructs with different isoform variants. Following transformation and recovery of transgenic lines, we observed that expression of the AalNix3&4 isoform could shift the alternative splicing of the sex determination genes, doublesex and fruitless, from female to male isoforms, and phenotypically masculinize females or completely convert females into males. Importantly, the sex-converted pseudo-males are fertile and capable of flight. Thus, AalNix is the primary signal for male sex determination in Aedes albopictus and provides a basis for sex segregation and further Cas9-mediated gene-drive population suppression.
Selective targeting of biting females to control mosquito-borne infectious diseases
22953B. B. Kojin, A. Compton, Z. N. Adelman and Z. Tu, Trends in Parasitology, 2022-06-13 06:48:00.
Mosquitoes are vectors for a number of infectious diseases. Only females feed on blood to provision for their embryos and, in doing so, transmit pathogens to the associated vertebrate hosts. Therefore, sex is an important phenotype in the context of genetic control programs, both for sex separation in the rearing facilities to avoid releasing biting females and for ways to distort the sex ratio towards nonbiting males. We review recent progress in the fundamental knowledge of sex determination and sex chromosomes in mosquitoes and discuss new methods to achieve sex separation and sex ratio distortion to help control mosquito-borne infectious diseases. We conclude by suggesting a few critical areas for future research.
Current Status of Mosquito Handling, Transporting and Releasing in Frame of the Sterile Insect Technique
22868J. Guo, X. Zheng, D. Zhang and Y. Wu, Insects, 13. 2022-06-10 07:44:12.
The sterile insect technique (SIT) and its related technologies are considered to be a powerful weapon for fighting against mosquitoes. As an important part of the area-wide integrated pest management (AW-IPM) programs, SIT can help reduce the use of chemical pesticides for mosquito control, and consequently, the occurrence of insecticide resistance. The mosquito SIT involves several important steps, including mass rearing, sex separation, irradiation, packing, transportation, release and monitoring. To enable the application of SIT against mosquitoes to reduce vector populations, the Joint Food and Agriculture Organization of the United Nations (FAO) and the International Atomic Energy Agency (IAEA) Centre (previously called Division) of Nuclear Techniques in Food and Agriculture (hereinafter called Joint FAO/IAEA Centre) and its Insects Pest Control sub-program promoted a coordinated research project (CRP) entitled “Mosquito handling, transport, release and male trapping methods” to enhance the success of SIT. This article summarizes the existing explorations that are critical to the handling and transporting of male mosquitoes, offers an overview of detailed steps in SIT and discusses new emerging methods for mosquito releases, covering most processes of SIT.
Inside the Plan to Release Life-Saving Mosquitoes
22903WIRED, 2022-06-10 06:28:48.
The Florida Keys Mosquito Control District is turning towards a novel tool to combat harmful insecticide-resistant mosquitoes like the Aedes aegypti. What are they doing exactly? They're releasing millions of genetically modified male mosquitoes engineered to reduce the population of Aedes aegypti. How exactly does this work? We'll break it down.
Combined Trojan Y Chromosome Strategy and Sterile Insect Technique to Eliminate Mosquitoes: Modelling and Analysis
23051J. Lyu, M. Gu, S. Wang and K. Cheng, Mathematical Problems in Engineering, 2022:2373350. 2022-05-27 15:09:13.
Sterile insect technique has been successfully applied in the control of agricultural pests; however, it has a limited ability to control mosquitoes. A promising alternative approach is the Trojan Y Chromosome strategy, which works by manipulating the sex ratio of a population through the introduction of YY supermales that guarantee male offspring. To take the advantages of both approaches, a combined Trojan Y chromosome strategy and sterile insect technique (TYC-SIT) strategy considering intraspecies competition is modeled. The pure TYC method is compared with the pure SIT method by cancelling one-state variable. The dynamical analysis leads to results on both local and global stabilities of this combined TYC-SIT model. Optimal control analysis is also implemented to investigate the optimal mechanisms for extinction of mosquitoes. In particular, the numerical results affirm that the combined TYC-SIT enables near elimination of mosquitoes and works better than the pure TYC or pure SIT method. These conclusions have great significance for species controls with an XX-XY sex determinism system or ZZ-ZW system.
Optimization of Aedes albopictus (Diptera: Culicidae) Mass Rearing through Cost-Effective Larval Feeding
22626M. Kavran, A. Puggioli, S. Šiljegović, D. Čanadžić, N. Laćarac, M. Rakita, A. Ignjatović Ćupina, F. Balestrino, D. Petrić and R. Bellini, Insects, 13. 2022-05-26 07:11:26.
Aedes (Stegomyia) albopictus (Skuse, 1895) is an invasive important medical and veterinary pest species. The sterile insect technique (SIT) involves the mass rearing of males, and their sterilization and release into the habitat to compete with wild males. Our research objective was to compare the effectiveness of three larval diet recipes (IAEA-BY, BCWPRL, and MIX-14) in the laboratory rearing of Ae. albopictus males to evaluate the available economical feeding alternatives. The separation of sexes was done in the pupal stage by sieving. Reared males were tested for flight capacity and longevity. The application of the BCWPRL diet resulted in a higher portion of sieved male pupae than females, but the development of males was the slowest, and the number of obtained males (pupae and adults) was lower compared to the other two diets. The adult mean survival time was the highest in males fed with MIX-14 and the lowest in males fed with IAEA-BY. Males fed by IAEA-BY also demonstrated higher initial mortality in the adult stage. The diets BCWPRL and MIX-14 are economically more convenient than IAEA-BY (2.28 and 5.30 times cheaper, respectively). The cheapest diet, MIX-14, might represent a candidate for replacing the effective but still expensive IAEA-BY larval diet, providing lower costs of sterile male production.
Reply to: Assessing the efficiency of Verily’s automated process for production and release of male Wolbachia-infected mosquitoes
22643J. E. Crawford, K. C. Hopkins, A. Buchman, T. Zha, P. Howell, E. Kakani, J. R. Ohm, N. Snoad, L. Upson, J. Holeman, P. Massaro, S. L. Dobson, F. S. Mulligan and B. J. White, Nature Biotechnology, 2022-05-26 06:34:15.
We appreciate the comments from Bouyer et al. under their mandate as a United Nations agency program (‘to promote the safe and appropriate use of nuclear techniques and related technologies in food and agriculture’) on our paper1 . The centuries-old fight against mosquito-borne disease has entered a new phase that is both exciting and fast-moving. Many promising technologies and techniques have been developed in the past 2 decades, including mosquito colonies stably infected with Wolbachia2 mosquitoes3,4, a CRISPR–Cas9-based gene drive5 nations of these techniques with older approaches (that is, irradiated Wolbachia releases6,7 , genetically modified sterile and even combi). In a world where more than half of all humans are at risk of contracting mosquito-borne diseases across a range of economic and geographic landscapes, we think that an array of tools will be needed to turn the tide against the massive public health burden of these diseases.
Assessing the efficiency of Verily’s automated process for production and release of male Wolbachia-infected mosquitoes
22641J. Bouyer, H. Maiga and M. J. B. Vreysen, Nature Biotechnology, 2022-05-26 06:27:58.
A paper by Crawford et al.1 titled ‘Efficient production of male Wolbachia-infected Aedes aegypti mosquitoes enables large-scale suppression of wild populations’ reports a mosquito control suppression trial carried out from2017 to 2018 in Fresco Country, California, USA1 . Between 7.5 million and 14.4 million Wolbachia-infected male mosquitoes were released during the study, which achieved suppression rates of 69% and 95%, respectively. Although the work provided important insights for future Aedes genetic control programs—particularly the information on the immigration of fertile females into release areas—the paper contains several omissions and errors. Below, we discuss how these relate to three main areas: regulatory oversight, entomological efficiency and, finally, cost efficiency.
Strategies to Mitigate Establishment under the Wolbachia Incompatible Insect Technique
23104S. Soh, S. H. Ho, J. Ong, A. Seah, B. S. Dickens, K. W. Tan, J. R. Koo, A. R. Cook, S. Sim, C. H. Tan, L. C. Ng and J. T. Lim, Viruses, 14. 2022-05-24 08:10:53.
The Incompatible Insect Technique (IIT) strategy involves the release of male mosquitoes infected with the bacterium Wolbachia. Regular releases of male Wolbachia-infected mosquitoes can lead to the suppression of mosquito populations, thereby reducing the risk of transmission of vector-borne diseases such as dengue. However, due to imperfect sex-sorting under IIT, fertile Wolbachia-infected female mosquitoes may potentially be unintentionally released into the environment, which may result in replacement and failure to suppress the mosquito populations. As such, mitigating Wolbachia establishment requires a combination of IIT with other strategies. We introduced a simple compartmental model to simulate ex-ante mosquito population dynamics subjected to a Wolbachia-IIT programme. In silico, we explored the risk of replacement, and strategies that could mitigate the establishment of the released Wolbachia strain in the mosquito population. Our results suggest that mitigation may be achieved through the application of a sterile insect technique. Our simulations indicate that these interventions do not override the intended wild type suppression of the IIT approach. These findings will inform policy makers of possible ways to mitigate the potential establishment of Wolbachia using the IIT population control strategy.
Quality Control and Mating Performance of Irradiated Glossina palpalis gambiensis Males
22546K. Ilboudo, K. Camara, E. W. Salou and G. Gimonnea, Insects, 13. 2022-05-19 08:04:34.
The biological quality of sterile male insects produced in a mass-rearing facility is a prerequisite for the success of the SIT, which is a component of area-wide integrated pest management (AW-IPM). Indeed, sterile male insects released in the field must have a good mating performance in order to compete with wild males, but they must also present the required level of sterility. In the present study, the biological quality of sterile male Glossina palpalis gambiensis produced in a mass-rearing insectary was assessed through quality control testing. The mating performance of irradiated males was assessed in walk-in field cages. Irradiation had no effect on adult emergence but significantly reduced the percentage of operational flies (from 89.58% to 79.87%) and male survival (from 5 to 4 days, on average). However, irradiation did not impact the sterile male insemination potential, with all females inseminated and more than 80% of the spermathecae completely filled. The rate of induced sterility in females was 89.67% due to a dose rate decrease of the radiation source. Moreover, sterile males were able to compete successfully with untreated fertile males for untreated females in walk-in field cages. This study confirmed that the flies were still competitive and stressed the importance of regularly checking the radiation source parameters.
Elimination of a closed population of the yellow fever mosquito, Aedes aegypti, through releases of self-limiting male mosquitoes
22519P. B. Patil, S. K. Dasgupta, K. Gorman, A. Pickl-Herk, M. Puinean, A. McKemey, B. Char, U. B. Zehr and S. R. Barwale, PLOS Neglected Tropical Diseases, 16:e0010315. 2022-05-16 09:19:04.
Author summary Aedes aegypti L. species is the primary vector responsible for transmission of the dengue virus worldwide including chikungunya, yellow fever and Zika virus. The experiment presented in the manuscript represents a study undertaken to demonstrate suppression of the wild type Ae. aegypti population in large outdoor field cages with natural exposure to the environment (physically-contained field cage facility) by sustained releases of male adults of OX513A Ae. aegypti strain. This investigation is a phase-2 contained study as per the World Health Organization guidelines for evaluation of genetically modified organisms and was recommended by the Indian regulatory board. This experiment demonstrates suppression of wild type Ae. aegypti population by sustained releases of OX513A male adults in a contained facility. The prospect of the project is to demonstrate and implement the technology for controlling/suppression of the Ae. aegypti vector in the open field environment.
Setting the world’s deadliest animal to self-destruct
22210A. Ossola, QUARTZ, 2022-05-08 15:29:34.
The mosquitoes are coming - and the, hopefully, they're going. This wee, British biotech company Oxitec plans to kick off a months-long experiment in which it will release billions of Aedes aegypti mosquitoes in California and Florida. But these aren't just any mosquitoes - they're genetically engineered so that they don't bite and will, if all goes according to plan, eventually reduce the population of mosquitoes in these areas.
State of Florida approves release of millions of genetically modified mosquitoes
22216H. Crawford, FIRSTCOAST NEWS, 2022-05-04 15:34:00.
The state of Florida has given the green light to Oxitec, a U-K biotechnology company, to release millions of genetically modified mosquitoes in Monroe County starting this Spring. It’s a controversial pilot program that began in the Florida Keys in 2021 to evaluate the effectiveness of Oxitec mosquitoes to control the invasive, disease-spreading Aedes aegypti mosquito. According to an email obtained by First Coast News, the Florida Department of Agriculture and Consumer Services (FDACS) approved extending the experimental use permit on Tuesday. The department says it does not and will not be making a formal announcement related to the issuance of any pesticide registration. “Yesterday, FDACS authorized the distribution and experimental use of OX5034 AEDES AEGYPTI (EPA EUP NO. 93617-EUP-2) in Florida,” an email from the Division of Agricultural Environmental Services read. The Florida Keys Mosquito Control District has been working with Oxitec on field trials. Since 2021, millions of genetically modified male Aedes aegypti mosquitoes have been strategically released in Monroe County as part of the Oxitec Mosquito Project. In March, the EPA approved the release of 2.4 billion more in Monroe County and California over the next two years under an experimental use permit. Oxitec had to get approval from each state before proceeding. The mosquitoes are designed to kill biting females before they mature.
Genetically Modified Mosquitoes May Protect The World From Disease
22213J. R. Learn, DISCOVER, 2022-05-04 15:29:48.
Forget lions, hippos or venomous spiders. Aedes aegypti mosquitoes may be among the deadliest wildlife in the world. Their bite is relatively harmless in normal circumstances. But many of these mosquitoes carry diseases they transmit from the blood of one host to another, including Zika, chikungunya, dengue and yellow fever. Like the related tiger mosquito that also carries these diseases, the Ae. aegypti are distinguished by black and white stripes along their legs. These mosquitoes thrive in urban areas, which makes the spread of the diseases they carry particularly insidious. They typically breed in small volumes of water, like in discarded tires and flower pots. But a new genetically engineered technology can get the mosquitoes to breed themselves out of existence. “We want to have a tool that’s going to have a real impact on disease transmission, and we want it to be accessible,” says Nathan Rose, head of regulatory affairs at Oxitec. “Our real focus has been on finding environmentally friendly ways of controlling pests.”
Brit firm sparks fury after ‘releasing genetically modified mosquitoes’ into wild
22069C. Lawrence-Jones, Daily Star, 2022-04-29 07:17:13.
A British company has sparked fury after releasing genetically modified mosquitoes into the wild that critics say could produce new strains of super-mozzies. UK-based Oxitec say they've hacked the insects' genetic make up and hope it will ultimately kill off all-female offspring wiping out huge colonies of the bug. Mosquitoes are some of the deadliest creatures in the world with mosquito-borne diseases killing around a million people every year. In time, Oxitec argue, the hybrids could wipe out mosquito-borne diseases like dengue and yellow fever. But the experimental release in California and Florida Keys, an island chain at the very tip of Florida in the U.S. has angered critics.
Pilot trial using mass field-releases of sterile males produced with the incompatible and sterile insect techniques as part of integrated Aedes aegypti control in Mexico
22224A. Martín-Park, A. Che-Mendoza, Y. Contreras-Perera, S. Pérez-Carrillo, H. Puerta-Guardo, J. Villegas-Chim, G. Guillermo-May, A. Medina-Barreiro, H. Delfín-González, R. Méndez-Vales, S. Vázquez-Narvaez, J. Palacio-Vargas, F. Correa-Morales, G. Ayora-Tal, PLoS Negl Trop Dis, 16:e0010324. 2022-04-26 15:46:43.
We implemented a controlled before-and-after quasi-experimental study in two suburban localities of Yucatan (Mexico): San Pedro Chimay (SPC), which received IIT-SIT, and San Antonio Tahdzibichén used as control. Release of wAlbB Ae. aegypti males at SPC extended for 6 months (July-December 2019), covering the period of higher Ae. aegypti abundance. Entomological indicators included egg hatching rates and outdoor/indoor adult females collected at the release and control sites. Approximately 1,270,000 lab-produced wAlbB-infected Ae. aegypti males were released in the 50-ha treatment area (2,000 wAlbB Ae. aegypti males per hectare twice a week in two different release days, totaling 200,000 male mosquitoes per week). The efficacy of IIT-SIT in suppressing indoor female Ae. aegypti density (quantified from a generalized linear mixed model showing a statistically significant reduction in treatment versus control areas) was 90.9% a month after initiation of the suppression phase, 47.7% two months after (when number of released males was reduced in 50% to match local abundance), 61.4% four months after (when initial number of released males was re-established), 88.4% five months after and 89.4% at six months after the initiation of the suppression phase. A proportional, but lower, reduction in outdoor female Ae. aegypti was also quantified (range, 50.0-75.2% suppression). CONCLUSIONS/SIGNIFICANCE: Our study, the first open-field pilot implementation of Wolbachia IIT-SIT in Mexico and Latin-America, confirms that inundative male releases can significantly reduce natural populations of Ae. aegypti. More importantly, we present successful pilot results of the integration of Wolbachia IIT-SIT within a IVM plan implemented by Ministry of Health personnel.
First U.S. Open-Air Test of Genetically Modified Mosquitoes Deemed a Success
21786S. Kuta, Smithosonian Magazine, 2022-04-21 06:47:16.
A private company that released genetically modified mosquitoes into the open air of the Florida Keys last spring says the experiment was a success, reports Emily Waltz for Nature. Oxitec, a United Kingdom-based biotech firm initially founded at Oxford University, released the bugs in an effort to curb wild mosquito populations. The company has not yet published data from the experiment, but representatives said during a webinar earlier this month that the results were promising. Oxitec had already tested the genetically modified mosquitoes in the field in Brazil, Panama, the Cayman Islands and Malaysia, according to Nature, but this was the first open-air trial of genetically modified mosquitoes in the United States.
Genetically modified mosquitoes for controlling vector-borne diseases? Successful trial gives hope
21821T. Deol, Down To Earth, 2022-04-21 06:07:50.
Preliminary results of an open-air study of genetically engineered mosquitoes — with an aim to suppress a wild population of virus-carrying mosquitoes — in the United States have shown promising results. The aim of the experiment by Oxitec, a United Kingdom-based biotechnology firm, is to reduce the population of wild Aedes aegypti mosquitoes that is a vector for viruses such as chikungunya, dengue, zika and yellow fever. The scientists engineered a gene that will kill the female offspring. The results, achieved after a decade-long fight for public acceptance and regulatory approvals, are not enough. Larger studies are needed to understand whether the goal can be achieved or not. Their findings, yet to be published, were released during a webinar on 6 April. The experiment began in April 2021 in the Florida Keys but not without resistance from the residents. Their concerns ranged from the modified mosquitoes harming people, its impact on mosquito-eating species and other unintended consequences such as the emergence of a deadly virus.
Release of genetically modified mosquitoes created to fight disease a success: Biotech firm
21818C. Greenberg, National Post, 2022-04-20 06:03:19.
The release of genetically modified mosquitoes in the United States created to fight disease has gone according to plan, biotechnology firm Oxitec says.The first phase of the pilot study consisted of releasing almost 5 million modified Aedes aegypti male mosquitoes in the Florida Keys, a group of islands off the southern tip of Florida, in April 2021. The results indicated that the method may eventually succeed in eradicating or downsizing the number of Aedes aegypti mosquitoes. Aedes aegypti only make up 4 per cent of the mosquito population in the Keys, but are responsible for spreading yellow fever, dengue, chikungunya and Zika virus, Oxitec said during an online seminar revealing their findings on April 6. “The mosquito is very difficult to control. It likes to live around people, in houses, under houses,” said Andrea Leal, executive director of the Florida Keys Mosquito Control District. “We’re also seeing an increase in resistance to a number of our adulticide products that we use for mosquito control, so at the end of it, we’re looking for new tools to put in our toolbox to help us control this particular mosquito.”
Tests of Genetically Modified Mosquitoes Prove Positive
21816R. Ellis, WebMD, 2022-04-20 05:59:18.
The first open-air study of genetically modified mosquitoes in the United States has yielded positive results, says Oxitec, the UK-based company that ran the study. However, Oxitec says larger tests are needed to determine whether the insects can suppress the disease-spreading mosquito population in the wild, according to Nature. Dengue, Zika, and yellow fever are some of the diseases the experiments hope to reduce. Scientists at Oxitec mass produced and genetically modified male Aedes aegypti mosquito eggs in a lab. The males were released into the wild to mate with females and pass along a gene designed to kill the female offspring, which are the only ones that bite and spread the diseases. The male offspring live on.
Genetically Modified Mosquitoes Work as Intended
21814M. L. Ford, NEWSER, 2022-04-19 05:54:33.
Results are in from a pilot study in Florida, where millions of genetically engineered mosquitoes were released into the wild. Some referred to it as the “Jurassic Park” experiment when it was announced last year, but—so far—everything is going to plan, according to UK biotech firm Oxitec. Per Nature, the experiment is part of a long-term plan to develop new tools in the fight against the invasive Aedes aegypti mosquito, which can carry dengue, Zika, and other gnarly viruses. Genetically modified male mosquitoes were released into the wild to mate with the local females; as hoped, affected female offspring died before reaching adulthood, and male offspring carried the engineered gene. By the way, the engineered males and their offspring do not bite humans. Ultimately, the hope is to suppress if not eradicate A. aegypti; however, this phase was focused on ensuring that the method works. In addition to preventing reproduction, the gene was successfully passed to succeeding generations of males for three months, and then it disappeared from the local population. Oxitec’s work is EPA-approved, and it works closely with state wildlife agencies. Similar experiments will soon begin in California. “I like the way they’re going about it,” Thomas Scott, an entomologist at UC-Davis, told Nature. “They’re doing it in a systematic, thoughtful way. So I’m encouraged.”
Biotech firm announces results from first US trial of genetically modified mosquito
21775E. Waltz, Nature, 2022-04-18 08:09:34.
Researchers have completed the first open-air study of genetically engineered mosquitoes in the United States. The results, according to the biotechnology firm running the experiment, are positive. But larger tests are still needed to determine whether the insects can achieve the ultimate goal of suppressing a wild population of potentially virus-carrying mosquitoes. The experiment has been underway since April 2021 in the Florida Keys, a chain of tropical islands near the southern tip of Florida. Oxitec, which developed the insects, released nearly five million engineered Aedes aegypti mosquitoes over the course of seven months, and has now almost completed monitoring the release sites. Based in Abingdon, UK, the firm reported the first results from the experiment during a webinar on 6 April, although it has not yet published the data.
The sterile insect technique is protected from evolution of mate discrimination
21768J. J. Bull and R. Gomulkiewicz, PeerJ, 10:e13301. 2022-04-18 07:53:47.
Background The sterile insect technique (SIT) has been used to suppress and even extinguish pest insect populations. The method involves releasing artificially reared insects (usually males) that, when mating with wild individuals, sterilize the broods. If administered on a large enough scale, the sterility can collapse the population. Precedents from other forms of population suppression, especially chemicals, raise the possibility of resistance evolving against the SIT. Here, we consider resistance in the form of evolution of female discrimination to avoid mating with sterile males. Is resistance evolution expected? Methods We offer mathematical models to consider the dynamics of this process. Most of our models assume a constant-release protocol, in which the same density of males is released every generation, regardless of wild male density. A few models instead assume proportional release, in which sterile releases are adjusted to be a constant proportion of wild males. Results We generally find that the evolution of female discrimination, although favored by selection, will often be too slow to halt population collapse when a constant-release implementation of the SIT is applied appropriately and continually. The accelerating efficacy of sterile males in dominating matings as the population collapses works equally against discriminating females as against non-discriminating females, and rare genes for discrimination are too slow to ascend to prevent the loss of females that discriminate. Even when migration from source populations sustains the treated population, continued application of the SIT can prevent evolution of discrimination. However, periodic premature cessation of the SIT does allow discrimination to evolve. Likewise, use of a ‘proportional-release’ protocol is also prone to escape from extinction if discriminating genotypes exist in the population, even if those genotypes are initially rare. Overall, the SIT is robust against the evolution of mate discrimination provided care is taken to avoid some basic pitfalls. The models here provide insight for designing programs to avoid those pitfalls.
Potential Adverse Effects of GE Mosquitoes Unknown
21773B. Giuffre, The Epoch Times, 2022-04-17 08:04:34.
“Safe and sustainable.” That’s what Oxitec, a British biological pest control company, calls its genetically modified (GM) or genetically engineered (GE) mosquito pesticide product. The company claims its product is nontoxic to humans and animals and won’t harm beneficial insects such as bees and butterflies. The experiment’s goal is to test the use of GE mosquitoes for reducing the transmission of diseases such as dengue, Zika, chikungunya, and yellow fever. The method of action is post-CRISPR, but uses similar gene engineering technology—inserting a double whammy into the Aedes aegypti male mosquito: a lethal gene and a fluorescent gene (for tracking). “The goal here is not to kill mosquitoes,” said epidemiologist Thomas Scott of the GE mosquito projects in Science magazine, “It’s to prevent people from getting infected and sick and dying.”
The plan to release genetically engineered mosquitoes in California
21703M. Petersen, Phys Org, 2022-04-12 08:50:04.
In the mosquito breeding rooms of British biotech company Oxitec, scientists line up fresh eggs, each the size of a grain of salt. Using microscopic needles, the white-coated researchers inject each egg with a dab of a proprietary synthetic DNA. For four days, Oxitec technicians care for the eggs, watching for those that hatch into wriggling brown larvae. Those "injection survivors," as the company calls them, face a battery of tests to ensure their genetic modification is successful. Soon, millions of these engineered mosquitoes could be set loose in California in an experiment recently approved by the federal government. Oxitec, a private company, says its genetically modified bugs could help save half the world's population from the invasive Aedes aegypti mosquito, which can spread diseases such as yellow fever, chikungunya and dengue to humans. Female offspring produced by these modified insects will die, according to Oxitec's plan, causing the population to collapse. "Precise. Environmentally sustainable. Non-toxic," the company says on its website of its product trademarked as the "Friendly" mosquito.
Genetically-Modified Mosquitos Could Soon Be Released in California
21693A. Madrigal, KQED, 2022-04-12 08:31:27.
Millions of genetically-modified, non-biting mosquitoes may soon be set loose in California after federal regulators gave the green light to a study aimed at preventing transmission of diseases like Zika and dengue. British biotech firm Oxitech says its technology alters male mosquitos to only produce viable male offspring, leading to population declines as females die off. While it may sound like the plot of a horror movie, the company says the new process is safe and necessary to address the growing global threat of mosquito-borne diseases. But some scientists and other critics say it could create even more virulent mosquitos, among other health and environmental risks. We’ll discuss the plan, which still requires state approval.
Genetically Modified Mosquitoes May Be Released in California, Experts Express Concern
21719Z. Papadakis, NEWSMAX, 2022-04-11 09:25:49.
Millions of genetically engineered mosquitos could soon be set loose in California in an effort to curb the disease-carrying Aedes aegypti mosquito population — but some experts are concerned that it could backfire. On March 7, Oxitec, a private company, obtained a permit from the U.S. Environmental Protection Agency to release its mosquitos in specific districts in Florida and California. The company reasoned that its genetically modified insects could help to save the world half of the world's population from the invasive Aedes aegypti mosquito which, according to Oxitec, increases the risk of transmission of dengue, chikungunya, Zika, yellow fever, and other diseases. "Given the growing health threat this mosquito poses across the U.S., we're working to make this technology available and accessible," Grey Frandsen, CEO of Oxitec, said in a statement. "These pilot programs, wherein we can demonstrate the technology's effectiveness in different climate settings, will play an important role in doing so. We look forward to getting to work this year."
Will genetic modification of mosquitoes take a bite out of insects’ population?
21708N. Patel, KCRW, 2022-04-11 08:58:40.
An invasive species of aggressive “ankle biters” called the Aedes aegypti mosquito is now in LA, and it’s spreading quickly. These tiny vampires can lay eggs in a space as small as a water-filled bottle cap, and they carry diseases like yellow fever and dengue. A British company called Oxitec is now trying to eradicate them through genetic modification. Oxitec will release millions of modified mosquitoes that can only produce female offspring that will die. Without an ability to reproduce, the mosquito population will collapse. The Environmental Protection Agency (EPA) granted the company a permit to release their modified mosquitoes in San Bernardino, Fresno, Stanislaus, and Tulare Counties.
An army of genetically engineered mosquitoes is about to be released
21705M. Menard, KNX NEWS, 2022-04-11 08:53:53.
A British biotech company has been altering the DNA of mosquitoes with the goal of killing off a more dangerous breed capable of spreading deadly diseases. And now they’re preparing to release their “friendly mosquitoes” into the wild. In California. Aedes aegypti is an invasive breed of mosquito that has been rapidly spreading throughout the state since their first detection about 10 years ago. It is a known carrier of such diseases as yellow fever, chikungunya and dengue.
California’s first genetically modified mosquitoes may soon be released
21698A. M. Asperin, FOX11 Los Angeles, 2022-04-10 08:41:01.
How would you feel about a few genetically engineered mosquitoes flying into your neighborhood? It's a possibility after the US Environmental Protection Agency on Friday approved pilot projects of Oxitec's mosquitoes in specific districts in California and Florida. The next step is for applications to be submitted to state regulators, who must approve the project for it to move forward.
In California, an army of genetically engineered mosquitoes awaits release. Will it backfire?
21652M. Petersen, Los Angeles Times, 2022-04-08 15:00:55.
In the mosquito breeding rooms of British biotech company Oxitec, scientists line up fresh eggs, each the size of a grain of salt. Using microscopic needles, the white-coated researchers inject each egg with a dab of a proprietary synthetic DNA. For four days, Oxitec technicians care for the eggs, watching for those that hatch into wriggling brown larvae. Those “injection survivors,” as the company calls them, face a battery of tests to ensure their genetic modification is successful. Soon, millions of these engineered mosquitoes could be set loose in California in an experiment recently approved by the federal government. Oxitec, a private company, says its genetically modified bugs could help save half the world’s population from the invasive Aedes aegypti mosquito, which can spread diseases such as yellow fever, chikungunya and dengue to humans. Female offspring produced by these modified insects will die, according to Oxitec’s plan, causing the population to collapse.
Federal Government Approves Release of Millions of Genetically Engineered Mosquitoes in California
21681A. Jose, The Western Journal, 2022-04-08 08:10:32.
Genetically modified Aedes aegypti mosquitoes could soon buzz around in California and Florida after the federal government greenlighted a plan to release the insects in the states. The project is spearheaded by biotechnology firm Oxitec, which, among other things, specializes in biological pest control solutions. “Oxitec’s Friendly™ safe, non-biting male mosquitoes are designed to suppress local wild populations of disease-spreading mosquitoes,” Oxitec’s website states. According to the company, the genetically modified mosquitoes have a “self-limiting gene,” which ensures that when the “Friendly™ mosquito males mate with wild females, their offspring inherit a copy of this gene.” The gene stops female offspring from maturing into adulthood, culling their reproducibility. However, male offspring carrying the gene will survive and pass those on to their offspring, the company said.
Billions of Genetically Modified Mosquitoes Are Set to Descend on California and Florida This Summer
21658J. Rossen, MENTAL FLOSS, 2022-04-06 15:11:44.
Californians may not know it on sight, but there’s going to be something different about their mosquitoes this summer. An invasive species of the bite-prone insects has been genetically modified in an attempt at controlling disease spread. According to Smithsonian, the Environmental Protection Agency (EPA) has approved plans by biotech firm Oxitec to release 2.4 billion male Aedes aegypti mosquitos in both California and Florida that have been altered so their genes can only participate in producing surviving male offspring. (Females will die before reaching adulthood.) The insects will be introduced as eggs, which will then hatch when exposed to water. Because male mosquitoes do not bite, the theory is that a declining female mosquito population will reduce transmission of Zika, yellow fever, dengue, and other infectious diseases that can be passed on to humans from the bites. The goal is halting outbreaks before they begin. In 2021, Oxitec released 144,000 genetically modified mosquitoes in the Florida Keys. The insects have also been introduced in Brazil, the Cayman Islands, Panama, and India. While there is no spread of such diseases in California, the firm says a growing mosquito population could eventually pose a problem and that such pilot programs are necessary to assess effectiveness
Genetically modified mosquitoes, a potential antidote to deadly diseases
21634TRTWorld, TRTWorld, 2022-04-01 08:08:35.
The US approved the release of billions of genetically modified mosquitoes to reduce the transmission of diseases but critics point to possible unintended consequences. Can genetically modified animals combat the spread of deadly diseases? The United States Environmental Protection Agency (EFA) thinks so. The agency has approved the release of over 2 billion mosquitoes that were genetically altered specifically to reduce the transmission of deadly transmissible diseases such as Zika, chikungunya, dengue, and yellow fever.The program in Florida and California will be put into action by the British biotechnology company Oxitec that genetically modify the mosquitos, mainly male Aedes aegypti eggs, in a lab. The mosquitos then will mate with females, only to pass the modified gene that would kill the female offspring. As a result, only the male offspring will stay alive as only the female ones spread the disease. The project also needs the approval of both states’ regulators and will be carried out in partnership with the Delta Mosquito and Vector Control district in Tulare county.
Comparison of Ground Release and Drone-Mediated Aerial Release of Aedes aegypti Sterile Males in Southern Mexico: Efficacy and Challenges
21574C. F. Marina, P. Liedo, J. G. Bond, A. R. Osorio, J. Valle, R. Angulo-Kladt, Y. Gómez-Simuta, I. Fernández-Salas, A. Dor and T. Williams, Insects, 13. 2022-03-31 12:43:15.
Sterile males of Aedes aegypti were released once a week for 8 weeks to evaluate the dispersal efficiency of ground and aerial drone release methods in a rural village of 26 Ha in southern Mexico. Indoor and outdoor BG-Sentinel traps were placed in 13–16 houses distributed throughout the village. The BG traps were activated 48 h after the release of the sterile males and functioned for a 24 h period following each release. Over the 8-week period of simultaneous ground and aerial releases, an average of 85,117 ± 6457 sterile males/week were released at ground level and 86,724 ± 6474 sterile males/week were released using an aerial drone. The ground release method resulted in higher numbers of captured males (mean = 5.1 ± 1.4, range 1.1–15.7 sterile males/trap) compared with the aerial release method (mean = 2.6 ± 0.8, range 0.5–7.3 sterile males/trap) (p < 0.05). Similarly, the prevalence of traps that captured at least one sterile male was significantly higher for ground release compared to the aerial release method (p < 0.01). The lower numbers of sterile males captured in the aerial release method could be due to mortality or physical injury caused by the chilling process for immobilization, or the compaction of these insects during transport and release. However, aerial releases by a two-person team distributed insects over the entire village in just 20 min, compared to ~90 min of work for a five-person team during the ground release method. Ground release also resulted in higher aggregations of males and some villagers reported feeling discomfort from the presence of large numbers of mosquitoes in and around their houses. We conclude that modifications to the handling and transport of sterile males and the design of containers used to store males are required to avoid injury and to improve the efficiency of aerial releases for area-wide SIT-based population suppression programs targeted at mosquito vectors of human disease.
Genetic Stability and Fitness of Aedes aegypti Red-Eye Genetic Sexing Strains With Pakistani Genomic Background for Sterile Insect Technique Applications
22452M. Misbah-ul-Haq, D. O. Carvalho, L. D. de la Fuente, A. A. Augustinos and K. Bourtzis, Frontiers in Bioengineering and Biotechnology, 10. 2022-03-31 09:37:56.
The mosquito species Aedes aegypti is the primary transmitter of viruses that cause endemic diseases like dengue in Pakistan. It is also a cause of other vector-borne diseases like yellow fever, Zika fever, and chikungunya, which significantly impact human health worldwide. In the absence of efficient vaccines (except for yellow fever) or drugs, vector control methods, such as the sterile insect technique (SIT), have been proposed as additional tools for the management of these diseases. Mosquito SIT programs are based on the release of sterile males and it is important female releases to be ideally zero or to be kept at a minimum, since females are the ones that bite, blood-feed and transmit pathogens. Recently, an Ae. aegypti genetic sexing strain (GSS), with and without a recombination-suppressing inversion (Inv35), was developed using the eye color as a selectable marker, with males having black eyes and females red eyes. In the present study, we introgressed the sexing features and the Inv35 of the Ae. aegypti red-eye GSS into the Pakistani genomic background aiming to their future use for SIT applications in the country. Both introgressed strains, the Red-eye GSS-PAK and the Red-eye GSS/Inv35-PAK, were evaluated in respect to their genetic stability and biological quality by assessing parameters like recombination rate, fecundity, fertility, pupal and adult recovery, time of development, pupal weight, survival, and flight ability in comparison with a wild Pakistani population (PAK). The results suggest that the sexing features and the recombination suppression properties of Inv35 were not affected after their introgression into the local genomic background; however, some biological traits of the two newly constructed strains were affected, positively or negatively, suggesting that a thorough quality control analysis should be performed after the introgression of a GSS into a new genomic background prior to its use in SIT field trials or applications. The importance of using GSS with local genomic background for SIT applications against Aedes aegypti is also discussed.
Why a U.S. Company Plans to Release 2.4 Billion Genetically Modified Mosquitoes
21569M. Osborne, Smithosonian Magazine, 2022-03-30 12:35:35.
The Environmental Protection Agency has cleared the release of 2.4 billion genetically-modified mosquitoes in California and Florida. The mosquitoes, created by biotech firm Oxitec, will be non-biting Aedes aegypti males engineered to only produce viable male offspring, per the company. Oxitec says the plan will reduce numbers of the invasive Aedes aegypti, which can carry diseases like Zika, yellow fever and dengue. Female mosquitoes will die, while males will reproduce and spread the self-limiting gene to the next generation, eventually leading to population declines. While these diseases aren’t yet spreading in California, the invasive insect has been flagged as a growing risk as their numbers increase across the state, reports the Guardian’s Gabrielle Canon. “Given the growing health threat this mosquito poses across the U.S., we’re working to make this technology available and accessible,” Oxitec CEO Grey Frandsen says in a statement. “These pilot programs, wherein we can demonstrate the technology’s effectiveness in different climate settings, will play an important role in doing so.”
US poised to release 2.4bn genetically modified male mosquitoes to battle deadly diseases
21571G. Canon, The Guardian, 2022-03-26 12:38:38.
Genetically modified male mosquitoes may soon be buzzing across areas of California, in an experiment to stop the spread of invasive species in a warming climate. Earlier this month, the EPA cleared the UK-based biotech company Oxitec to release a maximum of roughly 2.4bn of its genetically modified mosquitoes through 2024, expand its existing trial in Florida and start a new pilot project in California’s Central Valley, where mosquito numbers are on the rise. Oxitec’s modified mosquitoes are male, and therefore don’t bite. They were developed with a special protein so that when they pair with a female mosquito the only viable offspring they produce are also non-biting males. The project specifically targets the Aedes aegypti mosquito, one of more than 3,500 mosquito species and a dangerous invasive insect that has spread diseases like dengue, Zika, Chikungunya, and yellow fever in other countries.
Millions of genetically engineered mosquitoes are here to protect us
21551M. Kaufman, MASHABLE, 2022-03-26 12:06:29.
Aedes aegypti almost certainly traveled to California in cargo, like many invasive species do. The species, which flourishes in warmer climes, has colonized places like Los Angeles County, and is expected to multiply and spread in these temperate regions as the climate continuously warms. The invasive species has already thrived in the Gulf states for centuries. Crucially, Aedes aegypti aren't simply an itchy annoyance (the females voraciously bite for blood meals): The mosquitoes spread viral diseases like dengue fever, yellow fever, Zika, among others. Future outbreaks in new and old parts of the U.S. have a realistic, unsettling potential. To prepare, the U.S. Environmental Protection Agency recently allowed for the carefully regulated, experimental release of over 2.4 million genetically-modified mosquitoes in California and Florida over the next couple of years. It's a pilot project intended to prove that Aedes aegypti populations can be repressed by genetically-altered mosquitoes. The modified mosquitoes are non-biting males carrying a manipulated gene that, after mating, kills the insects' offspring. The biotechnology company Oxitec devised this mosquito-control strategy, and will run the tests.
Field Suppression of Spotted Wing Drosophila (SWD) (Drosophila suzukii Matsumura) Using the Sterile Insect Technique (SIT)
21241R. A. Homem, Z. Mateos-Fierro, R. Jones, D. Gilbert, A. R. McKemey, G. Slade and M. T. Fountain, Insects, 13. 2022-03-26 06:14:15.
Drosophila suzukii (spotted wing drosophila—SWD) is an economically important pest of soft and stone fruit worldwide. Control relies on broad-spectrum insecticides, which are neither fully effective nor environmentally sustainable. The sterile insect technique (SIT) is a proven, effective and environmentally friendly pest-management tool. Here, we investigated, for the first time, the potential of using SIT to control D. suzukii in field conditions without physical barriers that limit insect invasion. A proprietary method of rearing and irradiation with X-rays was used to obtain males that were 99% sterile. Sterile males were released twice per week from April to October 2021 on a site in Kent, UK, where everbearing strawberries were grown in open polytunnels. The infestation of wild female D. suzukii was monitored weekly using red sticky traps with dry lure at the treated site and at two similar control sites that did not receive sterile male releases. Releases of sterile males suppressed the wild female D. suzukii population by up to 91% in comparison with the control sites. We thus demonstrated the feasibility of SIT to achieve season-long control of D. suzukii using early, sustained and dynamically targeted releases of sterile males. This provides a promising environmentally friendly method to control this important pest.
A scourge of genetically modified mosquitoes could be unleashed in California
21236J. Bote, SFGATE, 2022-03-21 05:16:37.
A genetically modified scourge of mosquitoes could be unleashed throughout California as municipalities across the state grapple with increasing bouts of an invasive mosquito species. The mosquitoes, developed by the British biotech firm Oxitec, are known as OX5034 — a modified male version of Aedes aegypti, the species that first emerged in Los Angeles County about a decade ago before spreading to at least 22 different counties across the state. They are an invasive species known to carry dengue, Zika and a host of other diseases, and naturally spread in contained, urban spaces with standing water, such as flowerpots and open water bottles. Up to 2 million OX5034 mosquitoes could be released in the coming years throughout the state, pending state approval by the California Department of Pesticide Regulation. The male species, which naturally do not bite humans, carry a gene that will ensure that female offspring do not grow into childhood. Male offspring, however, will survive — and continue to pass down the gene to further generations, hopefully eradicating the invasive species for good.
An agent-based model to simulate the boosted Sterile Insect Technique for fruit fly management
22556E. G. Diouf, T. Brévault, S. Ndiaye, E. Faye, A. Chailleux, P. Diatta and C. Piou, Ecological Modelling, 468:109951. 2022-03-18 14:58:33.
The sterile insect technique (SIT) is a method of biological control of pests and disease vector insects. It includes mass-rearing and release of sterile males of the target species so that wild females mated with sterile males would not produce offspring. An innovative version of this technique, called boosted SIT, relies on the use of sterile males as vectors of biocides to trigger an epizootic in the wild fruit fly population. We built an agent-based model to assess the feasibility of this technique and main modalities of field implementation for the control of the Oriental fruit fly, Bactrocera dorsalis, using the entomopathogenic fungi, Metarizhium anisopliae, as a biocide. The model, called BOOSTIT (BactrOcera dOrsaliS boosTed sIT), simulates the spatio-temporal population dynamics of fruit flies in three different realistic landscape contexts. The releases of infected and uninfected sterile males were simulated and allowed the transmission of the pathogen within the wild fly population as a result of interactions between individuals. A main output was the measurement of losses in mango production. Validation of the model was done by comparing the simulated population dynamics with data from field monitoring (pheromone traps) in three landscapes of the Niayes area in Senegal. The population dynamics of wild flies were then simulated in an intensive cropping and mono-mango cultivar landscape under three scenarios: (1) without the release of sterile males, (2) with the release of non-contaminated sterile males (SIT) and (3) with the release of sterile contaminated males (boosted SIT). The results showed that SIT and boosted SIT strongly reduced the density of wild flies and the amount of infested fruits. Although parameters of the pathogen transfer between individuals need to be studied more deeply, results encourage the implementation of field trials to validate the efficacy of boosted SIT to control fruit flies.
Could species-focused suppression of Aedes aegypti, the yellow fever mosquito, and Aedes albopictus, the tiger mosquito, affect interacting predators? An evidence synthesis from the literature
20971J. A. S. Bonds, C. M. Collins and L.-C. Gouagna, Pest Management Science, 2022-03-16 07:20:33.
The risks of Aedes aegypti and Aedes albopictus nuisance and vector-borne diseases are rising and the adverse effects of broad-spectrum insecticide application has promoted species-specific techniques, such as sterile insect technique (SIT) and other genetic strategies, as contenders in their control operations. When specific vector suppression is proposed, potential effects on predators and wider ecosystem are some of the first stakeholder questions. These are not the only Aedes vectors of human diseases, but are those for which SIT and genetic strategies are of most interest. They vary ecologically and in habitat origin, but both have behaviourally human-adapted forms with expanding ranges. The aquatic life stages are where predation is strongest due to greater resource predictability and limited escape opportunity. These vectors' anthropic forms usually use ephemeral water bodies and man-made containers as larval habitats; predators that occur in these are mobile, opportunistic and generalist. No literature indicates that any predator depends on larvae of either species. As adults, foraging theory predicts these mosquitoes are of low profitability to predators. Energy expended hunting and consuming will mostly outweigh their energetic benefit. Moreover, as adult biomass is mobile and largely disaggregated, any predator is likely to be a generalist and opportunist. This work, which summarises much of the literature currently available on the predators of Ae. aegypti and Ae. albopictus, indicates it is highly unlikely that any predator species depends on them. Species-specific vector control to reduce nuisance and disease is thus likely to be of negligible or limited impact on non-target predators
Billions of GE Mosquitoes May Soon Be Released in California and Florida
21009A. N. Mitra, Earth Island Journal, 2022-03-16 06:18:31.
he US Environmental Protection Agency’s decision last week to allow the release of billions of genetically engineered mosquitoes in California and Florida has several environmental and public health groups worried about the potential impacts of the experimental releases on public health and the environment. The EPA move follows last year’s pilot field trial in the Florida Keys where, starting April 2021, the British biotechnology company Oxitec and the Florida Keys Mosquito Control released half a billion of these transgenic mosquitoes. The purpose was to test if they could help reduce populations of Aedes aegypti, a mosquito species that can carry viruses that cause deadly diseases like yellow fever, dengue, chikungunya, and Zika — none of which are major concerns in the United States.
Evaluation of Additional Drosophila suzukii Male-Only Strains Generated Through Remobilization of an FL19 Transgene
25425A. Yamamoto, A. K. Yadav and M. J. Scott, Frontiers in Bioengineering and Biotechnology, 10. 2022-03-15 08:27:00.
Drosophila suzukii (D. suzukii) (Matsumura, 1931; Diptera: Drosophilidae), also known as spotted wing Drosophila, is a worldwide pest of fruits with soft skins such as blueberries and cherries. Originally from Asia, D. suzukii is now present in the Americas and Europe and has become a significant economic pest. Growers largely rely on insecticides for the control of D. suzukii. Genetic strategies offer a species-specific environmentally friendly way for suppression of D. suzukii populations. We previously developed a transgenic strain of D. suzukii that produced only males on a diet that did not contain tetracycline. The strain carried a single copy of the FL19 construct on chromosome 3. Repeated releases of an excess of FL19 males led to suppression of D. suzukii populations in laboratory cage trials. Females died as a consequence of overexpression of the tetracycline transactivator (tTA) and tTA-activated expression of the head involution defective proapoptotic gene. The aim of this study was to generate additional male-only strains that carried two copies of the FL19 transgene through crossing the original line with a piggyBac jumpstarter strain. Males that carried either two chromosome 3 or a singleX-linked transgene were identified through stronger expression of the red fluorescent protein marker gene. The brighter fluorescence of the X-linked lines was likely due to dosage compensation of the red fluorescent protein gene. In total, four X-linked lines and eleven lines with two copies on chromosome 3 were obtained, of which five were further examined. All but one of the strains produced only males on a diet without tetracycline. When crossed with wild type virgin females, all of the five two copy autosomal strains examined produced only males. However, the single copy X-linked lines did not show dominant female lethality. Five of the autosomal lines were further evaluated for productivity (egg to adult) and male competition. Based on these results, the most promising lines have been selected for future population suppression experiments with strains from different geographical locations.
California’s first lab-grown mosquitoes may take flight—stirring controversy
21022L. M. Krieger, Phys Org, 2022-03-15 06:51:22.
A biotech firm is seeking permission to release genetically modified mosquitoes into the open air of California for the first time later this year, aiming to reduce the expanding populations of invasive mosquitoes and prevent deadly disease. The controversial research project—planned for the Tulare County community of Visalia, with potential expansion into Fresno, San Bernadino and Stanislaus counties—will over time introduce 2 million male mosquitoes with a "kill switch" built into their DNA. When they mate with wild insects, their offspring die, causing an eventual collapse of the population. Their target: Swarms of the mosquito, first detected in Los Angeles County in 2011, which have since spread northward into 20 California counties. While California's native mosquito emerges at dusk, these black-and-white-striped invaders hunt for blood during the day, when people are outside. Elsewhere, they transmit potentially fatal Zika, dengue, yellow fever, chikungunya and other viruses.
Fall armyworms with offspring-killing gene tested on farms in Brazil
21020M. Le Page, New Scientist, 2022-03-15 06:46:51.
Fall armyworms genetically modified to wipe out wild populations of the pests have been released in corn fields in São Paulo State in Brazil in the first farm trial of the new technology. The test was a success and is now being expanded, says Oxitec, the UK-based company that created the modified armyworms. Fall armyworms (Spodoptera frugiperda) are in fact moth caterpillars. They get their name from the fact that they multiply very fast and feed on many plants. Swarms of armyworms can devastate everything from lawns to crops in just days. They are native to the Americas, but in recent years have spread across Africa, Asia and Australia, reducing harvests of some crops by up to half. Conventional control methods aren’t working well because some strains have evolved resistance to many pesticides. “There is a lot of interest in new solutions to this pest,” says Neil Morrison at Oxitec. “Growers are struggling to control it through insecticidal means.” For its method of control, Oxitec took a strain of fall armyworm that is still susceptible to pesticides and modified males so that their female offspring can survive only in the presence of a specific chemical. In other words, the males carry a gene that kills all their female offspring in the wild.
Genetically modified mosquitoes kill their own offspring
21024C. Ward, SYFY, 2022-03-14 06:55:40.
Oxitec, a biotech company, has developed a strain of A. aegypti which they call Friendly. Their modified mosquitos are all males and carry a gene which prevents the birth of females in subsequent generations. In short, they’re reducing disease-carrying mosquitos by killing their babies before they hatch. The Environmental Protection Agency has granted permission for the release of the experimentally modified mosquitos in Florida, and those same mosquitos may soon be released in California. While the federal government has agreed to the program, permission must also be obtained from the states where the releases will occur before they can proceed. Should California grant permission, populations of modified mosquitos could be released in Stanislaus, Fresno, Tulare, and San Bernadino counties soon. Once released, modified male mosquitos breed with wild females, delivering the desired gene sequence to the next generation. Any females in the next generation are terminated before being born and all males which are produced carry the same gene, allowing them to continue the cycle through several generations. Oxitec considers the modification inherently self-limiting and estimates that it will vanish from the overall population after a few generations, at which point mosquito populations will return to normal reproduction.
Combining two Genetic Sexing Strains allows sorting of non-transgenic males for Aedes genetic control
20642C. Lutrat, M. Burckbuchler, R. P. Olmo, R. Beugnon, A. Fontaine, T. Baldet, J. Bouyer and E. Marois, bioRxiv, 2022.03.11.483912. 2022-03-12 08:15:59.
Chemical control of the mosquito vectors Aedes albopictus and Aedes aegypti is costly, unsustainable, and increasingly ineffective due to the spread of insecticide resistance. The Sterile Insect Technique is an autocidal control tactic that represents a valuable alternative but is limited by the slow, error-prone, and wasteful sex-separation stage. Here, we present four genetic sexing strains (two for each Aedes species) based on fluorescence markers linked to the m and M sex loci, allowing the isolation of transgenic males. Furthermore, we show how combining these sexing strains allows the production of non-transgenic males. Scaling-up would allow the sorting of 100,000 neonate male larvae in under 1.5 hour with 0.01-0.1% female contamination. The resulting males present similar survival and flight ability to laboratory-reared wild-type males. By facilitating the sorting of transgenic or non-transgenic males, these Genetic Sexing Strains should enable a major upscaling in control programmes against these major vectors.Competing Interest StatementThe authors have declared no competing interest.
Millions Of Genetically Modified Mosquitoes To Be Set Loose In US
20638H. Wilmerding, Daily Caller, 2022-03-11 08:11:40.
Millions of genetically modified mosquitoes will be released in the United States as part of an initiative to replace the insects carrying deadly diseases, the company behind the plan announced Tuesday. The program, led by biotechnology company Oxitec, will release roughly 2 million genetically altered mosquitoes in California and Florida to fend off other mosquitoes carrying deadly diseases like Zika, yellow fever, dengue and chikungunya, the company said in a press release. The Environmental Protection Agency (EPA) approved Oxitec’s plan on March 8. “Given the growing health threat this mosquito poses across the U.S., we’re working to make this technology available and accessible,” Oxitec chief executive officer Grey Frandsen said in the press release.
Florida Begins Release of Genetically Altered Mosquitoes to Prevent Spread of Zika
20632Entrepreneur staff, Entrepreneur, 2022-03-11 08:01:36.
Since 2016, Zika , a disease transmitted by a virus that spreads an invasive species of mosquito, has plagued various regions of the world, including areas of Florida and Texas in the United States. In May 2020, the Environmental Protection Agency (EPA) approved a program to release millions of genetically altered mosquitoes that, in theory, will help reduce the population of female Aedes aegypti specimens, the species that carries the virus. n 2016, the disease became a public health issue throughout the world and caused multiple cases of a condition called microcephaly, in babies of women who were infected during pregnancy. Infected babies were born with smaller heads than expected due to partial collapse of the skull and limited movement in some of their joints. The Zika virus has spread to more than 30 countries, including Bolivia, Brazil, Guatemala, Honduras, Venezuela, El Salvador, Mexico, and parts of the United States.This week the first step was taken in a program that, if successful, could culminate in the release of up to 750 million genetically altered flies that would help control the spread of the disease. The first phase will last 12 weeks and will consist of introducing up to 12,000 genetically modified eggs in small areas. In theory, the specimens that hatch from these eggs are capable of transmitting a gene that only kills the females (they are the ones that bite and infect people) before they reach adulthood and start biting.
2 Billion Genetically Modified Mosquitoes Have Been Approved For Release In Florida And California
20609J. U. Nisa, Wonder Engineering, 2022-03-10 12:21:31.
The US Environmental Protection Agency (EPA) has sanctioned the release of 2 billion genetically modified mosquitos in Florida and California, Oxitec, the company that created the genetically modified mosquitoes, said. Oxitec’s experimental program intends to reduce the spread of hazardous diseases like dengue, Zika, and yellow fever by destroying the offspring of a common type of mosquito, Aedes aegypti, which transmits diseases through its sting. Scientists at Oxitec, located in the United Kingdom, mass generate and genetically engineer male Aedes aegypti eggs in a lab. These male mosquitos will be released into the wild to mate with females and pass on a gene that kills the female offspring, which are the only ones that sting and carry disease. The male offspring survive.
Billions of genetically modified male mosquitos will be released in California and Florida as a ‘natural pest control’ to stop the spread of diseases like Zika, yellow fever and Dengue
20599R. Morrison, Daily Mail, 2022-03-10 12:07:54.
Billions of genetically engineered male mosquitos will be released in California and Florida over the next two years, as part of a mission to kill off biting females. Oxitec, based in Oxford UK, is a biological pest control development firm, that has produced the edited version of the flying insects to combat mosquito-borne diseases like Dengue, yellow fever and Zika. Male Aedes aegypti mosquitos don't bite humans, but females do, and so the genetic modification causes females to die off soon after being born. The project has been cleared by the Environmental Protection Agency (EPA), and the first wave is due to be released this year, although it isn't clear exactly when this will happen, as it requires state regulatory approval in Florida and California. It isn't likely to be a problem in Florida, as the state played host to a trial last year that saw millions of the same type of Oxitec mosquitos released in the Florida Keys.
2 billion genetically modified mosquitos are about to be released in the US
20635J. Hawkins, yahoo, 2022-03-10 08:06:35.
Scientists have been playing god with mosquitos for a couple of years now. Back in 2021, British company Oxitec released 750 million lab-modified mosquitos in Florida. Now, the company is gearing up to release another 2 billion genetically modified mosquitos across more of Florida and in California as well.The new species, codenames OX5034, is made up entirely of male mosquitos. The new species is derived from the Aedes aegypti family of mosquitos. Just like others the company has released, this new 2 billion should produce larvae that die off before they reach adulthood. This is thanks to the self-limiting gene that Oxitec has created. The new gene essentially disrupts the generation of essential proteins the larvae need to develop. Without the needed proteins, it is unable to complete its development process.
2 Billion Genetically Altered Mosquitoes Will Be Released in Fla. and Calif. to Fight Disease
20628A. Adams, People, 2022-03-10 07:50:39.
Billions of genetically modified mosquitoes are expected to be released within the next two years as part of an expanded version of an Environmental Protection Agency (EPA) study — but the project is receiving criticism from advocacy groups that believe it could be dangerous.The EPA said in an announcement on Monday that it will extend its current study into reducing the population of the Aedes aegypti, a mosquito commonly found in the United States, through April 2024. The EPA looking to broaden its work to Monroe County in Florida and four counties in California: Stanislaus, Fresno, Tulare and San Bernardino. Under the project's revised Experimental Use Permit (EUP), the EPA is permitted to release nearly 2.5 billion Aedes aegypti mosquitoes containing a protein called Tetracycline Trans-Activator Variant (tTAV-OX5034) into the wild.
Genetically modified mosquitoes could be tested in California soon
20605S. Milius, Science News, 2022-03-09 12:15:25.
Genetically modified mosquitoes might soon be whining on both U.S. coasts. The U.S. Environmental Protection Agency has approved two more years of testing Oxitec’s genetically modified mosquitoes as living pest controls, continuing a pilot program started in 2021 in the Florida Keys and expanding it to up to four counties in California. Now the Florida and California state governments will consider whether to grant permission. The male mosquitoes, OX5034 Aedes aegypti engineered by the biotech company Oxitec, carry daughter-killing genes that get passed generation to generation. When these males mate with local females outside a lab, only the sons should survive. Those inheriting the sabotage gene will grow up to mate with normal females, dooming their daughters too.
Why millions of genetically modified mosquitoes could be released across US
20601J. Rogers, New York Post, 2022-03-09 12:11:08.
The US could soon be swarming with genetically altered mosquitoes after the Environmental Protection Agency approved a plan to test the insects. It is hoped the new altered mosquitoes will ward off their natural, disease-causing counterparts. Biotechnology company Oxitec has developed altered Aedes aegypti mosquitoes which have been genetically modified so that males, which do not bite, are released into the wild and mate with females, which do bite. Their offspring, either male or female, never survive to reach maturity, according to the company.
Genetically Modified Mosquitoes May Be Released in Fla and Calif
20597R. Ellis, WebMD, 2022-03-09 12:04:50.
The U.S. Environmental Protection Agency has approved the release of 2 billion genetically altered mosquitoes in Florida and California, the company that created the genetically modified mosquitoes said. The experimental program created by Oxitec is designed to reduce the transmission of harmful diseases such as dengue, Zika, and yellow fever. The program is an extension of one in which millions of mosquitoes were released last year in the Florida Keys, USA Today reported. State agencies in Florida and California will have to approve the programs before the releases occur. The aim of the program is to reduce cases of diseases like yellow fever by killing off the offspring of a common kind of mosquito, Aedes aegypti, which spreads diseases through its bite.
2 Billion Genetically Modified Mosquitoes Cleared for Release in California and Florida
20595E. Cara, gizmodo, 2022-03-09 11:59:00.
British biotech firm Oxitec announced this week that it has received approval from the U.S. Environmental Protection Agency for its genetically modified mosquitoes to be released in parts of Florida and in California, following the completion of a pilot program last year. The modified male insects are designed to produce infertile offspring, ideally reducing local populations and rates of mosquito-borne illness. The male mosquitoes developed by Oxitec—codenamed species OX5034—are derived from Aedes aegypti, a notorious carrier of many diseases, including Zika, dengue, and yellow fever. When these mosquitoes mate with the native females in an area, they’re said to produce female larvae that simply die off before reaching adulthood, thus dooming the population as a whole. And because only female mosquitoes bite and suck blood from humans, the modified insects are thought to pose no danger to people.
Genetically Modified Mosquitoes Set to Be Released in California and Florida
20591K. Roberts, The Epoch Times, 2022-03-09 11:33:43.
Millions of genetically modified mosquitoes are set to be released in California and Florida in an effort to reduce the number of real, disease-carrying invasive mosquitoes. The U.S. Environmental Protection Agency on Monday approved use of the genetically engineered insects in pilot projects in specific districts across both states. The mosquitoes were made by UK-based biotechnology firm Oxitec, which is funded by the Bill and Melinda Gates Foundation, in an effort to combat insect-borne diseases such as dengue fever, yellow fever, and the Zika virus. According to Oxitec, its “sustainable and targeted biological pest control technology does not harm beneficial insects like bees and butterflies and is proven to control the disease-transmitting Aedes aegypti mosquito, which has invaded communities in Florida, California, and other U.S. states.” Since it was first detected in California in 2013, the Aedes aegypti mosquito has spread rapidly to more than 20 counties throughout the state, increasing the risk of mosquito-borne diseases being transmitted to humans.
No Sting in the Tail for Sterile Bisex Queensland Fruit Fly (Bactrocera tryoni Froggatt) Release Programs
20589O. L. Reynolds, D. Collins, B. C. Dominiak and T. Osborne, Insects, 2022-03-09 11:29:49.
Global markets do not tolerate the presence of fruit fly (Tephritidae) in horticultural produce. A key method of control for tephritidae pests, is the sterile insect technique (SIT). Several countries release a bisex strain, i.e., males and females, however the sterile male is the only sex which contributes to wild population declines when released en masse. In commercial orchards, there are concerns that sterile females released as part of bisex strains, may oviposit, i.e., ‘sting’ and cause damage to fruit, rendering it unmarketable. Australia has released a bisex strain of sterile Queensland fruit fly, Bactrocera tryoni Froggatt, for several decades to suppress wild pest populations, particularly in peri-urban and urban environments. Here, we assessed fruit damage in two commercially grown stone fruit orchards where bisex sterile B. tryoni were released, and in an orchard that did not receive sterile flies. The number of detected stings were higher in only one SIT release orchard, compared with the control; however, there was no difference between SIT and control orchards in the number of larvae detected. We showed that there is no evidence that sterile female B. tryoni released in large numbers caused stings, or damage that led to downgraded or unsaleable fruit. The bisex strain of sterile B. tryoni is recommended for use in commercial stone-fruit orchards, under the conditions in which this trial was conducted.
Proposed moquito release for Tulare County draws concern
20584E. Smith, The Business Journal, 2022-03-08 11:20:42.
News of the approval to release genetically-modified mosquitoes in Tulare County and Monroe County, Florida has drawn the ire of activists who say the company behind the project has not provided data demonstrating the insects are safe. At the same time, the company says it has the studies to demonstrate the safety of the program it calls “another tool in the integrated approach to pest control.” The U.S. Environmental Protection Agency has granted U.K.-based Oxitec an experimental-use permit giving the company the first green light to release male, non-biting mosquitoes in Tulare County and Monroe County in Florida, according to Rajeev Vaidyanathan, director of operations for Oxitec. The test is to see whether the engineered mosquitoes can reduce the number of Aedes aegypti mosquitoes that have spread throughout the country with the potential to carry tropical diseases such as dengue, yellow fever, Zika and chikungunya. Before they can begin the program, the California Department of Pesticide Regulations has to approve the proposal.
Millions of genetically modified mosquitoes may soon be buzzing in Florida and California. Here’s why.
20582R. W. Miller, USA Today, 2022-03-08 11:13:28.
Millions of genetically altered mosquitoes that seek to ward off their natural, disease-causing counterparts may soon be released in Florida and California after the Environmental Protection Agency approved a plan to further test the modified insects. Developed by the biotechnology company Oxitec, the Aedes aegypti mosquitoes are genetically modified so that males, which do not bite, are released into the wild and mate with females, which do bite. Their offspring are either male or females that never survive to reach maturity, the company says. Millions of the mosquitoes were released in the Florida Keys in a pilot project last year, and the EPA has authorized the extension of the project in Florida as well as the expansion into four counties in California, pending approval from the states' regulators.
‘Halt this nightmare immediately’: EPA approves release of genetically-engineered mosquitoes
20579J. Corbett, AlterNet, 2022-03-08 11:05:13.
Environmental and public health advocates responded with alarm after the Biden administration on Monday gave a British biotechnology company a green light to unleash billions of genetically engineered mosquitoes in the United States. The Environmental Protection Agency (EPA) granted Oxitec an experimental use permit that could lead to the release of genetically engineered (GE) mosquitoes in four California counties and extend a widely criticized program in Florida's Monroe County. While the release is intended to investigate whether the GE mosquito can reduce the population of Aedes aegypti mosquitoes—which carry various viruses—the species is not common in California and there are no reported cases of the targeted diseases. "This experiment is unnecessary and even dangerous, as there are no locally acquired cases of dengue, yellow fever, chikungunya, or Zika in California," declared Jaydee Hanson, policy director for the International Center for Technology Assessment and Center for Food Safety. Oxitec's altered male mosquitoes are supposed to pass on a gene that causes their offspring to die before reaching maturity. However, a peer-reviewed study published in September 2019 by Yale University researchers showed that releasing the GE mosquitoes in Brazil not only failed to reduce populations of Aedes aegypti but also resulted in hybrid mosquitoes.
Genetically Engineered Mosquito Imminent Mass Release Ignores Science, Public Health and Environmental Risks
20577H. Bourque, Friends of the Earth, 2022-03-07 11:00:22.
In defiance of science and public health concerns, today the Environmental Protection Agency (EPA) approved the mass release of billions of experimental genetically engineered (GE) mosquitoes into the United States’ most populous and agriculturally significant states. The biotechnology company Oxitec was granted an Experimental Use Permit for the release of a genetically engineered version of the species Aedes aegypti across Fresno, Tulare, San Bernadino and Stanislaus Counties in California and in Monroe County in Florida. This will be the biggest release of GE insects in the world. EPA’s approval came despite growing concerns raised by scientists, public health experts and environmental groups about potential impacts of the experimental releases to public health, the environment and endangered species. No publicly available data supports Oxitec’s claims that GE mosquitoes will reduce incidence of mosquito borne diseases. An independent peer-reviewed study from Yale University scientists revealed that over two years of continual releases of the GE mosquitoes at a test site in Brazil failed to reduce populations of Aedes aegypti. The Yale study also found that the GE mosquitoes bred with local Aedes aegypti, resulting in hybrid mosquitoes in the wild that may be more aggressive, more difficult to eradicate and may increase the spread of mosquito-borne disease.
GMO mosquitoes set for release in California to quell disease
20572M. Renda, Courthouse News Service, 2022-03-07 10:48:47.
The U.S. Environmental Protection Agency approved the experimental use of genetically engineered mosquitoes in California and Florida to reduce the populations of invasive mosquitoes that carry a host of infectious diseases like Zika and dengue fever. “With mosquito and vector-borne diseases a growing concern in California, we see Oxitec’s technology as an important additional option to control the invasive Aedes aegypti mosquito,” said Dr. Mustapha Debboun, general manager of the Delta Mosquito and Vector Control District, a government agency in the Central Valley. “We look forward to working in partnership with Oxitec and have been impressed with results from their previous projects in Brazil and the Florida Keys.” The Aedes aegypti mosquitoes were historically relegated to tropical and subtropical zones but have since invaded every continent on Earth except Antarctica. They are capable of bringing the diseases that plague tropical regions with them.
New tech fights fall armyworm by letting offspring die
20568V. Ouma, Sci Dev Net, 2022-03-01 09:43:19.
Scientists have developed a new technology that could control the devastating fall armyworm crop pest by releasing genetically-controlled males that suppress populations as subsequent offspring cannot survive, a study says. The fall armyworm, Spodoptera frugiperda, which was detected in Sub-Saharan Africa for the first time in 2016, could lead to one-third maize yield losses in some countries and up to US$6.3 billion loss annually, according to the study published in the journal BMC Biotechnology. The gene technology developed by Oxitec, a UK-based biotechnology company that genetically modifies insects to assist in insect control, enables production of male-only cohorts of the friendly fall armyworm that when released into farmer fields will mate with pest female fall armyworms, and their female offspring cannot survive, resulting in fewer pests on the crops and therefore less damage
Increased biting rate and decreased Wolbachia density in irradiated Aedes mosquitoes
20487R. Moretti, E. Lampazzi, C. Damiani, G. Fabbri, G. Lombardi, C. Pioli, A. Desiderio, A. Serrao and M. Calvitti, Parasites and Vectors, 15:67. 2022-02-24 08:48:28.
Releasing considerable numbers of radiation-sterilized males is a promising strategy to suppress mosquito vectors. However, releases may also include small percentages of biting females, which translate to non-negligible numbers when releases are large. Currently, the effects of irradiation on host-seeking and host-biting behaviors have not been exhaustively investigated. Information is also lacking regarding the effects of sterilizing treatment on the endosymbiotic bacterium Wolbachia, which is known to affect the vector competence of infected mosquitos.
Adult mosquito predation and potential impact on the sterile insect technique
21014N. S. Bimbilé Somda, H. Maïga, W. Mamai, T. Bakhoum, T. Wallner, S. B. Poda, H. Yamada and J. Bouyer, Scientific Reports, 12:2561. 2022-02-15 06:32:02.
The sterile insect technique is a promising environmentally friendly method for mosquito control. This technique involves releasing laboratory-produced sterile males into a target field site, and its effectiveness may be affected by the extent of adult mosquito predation. Sterile males undergo several treatments. Therefore, it is vital to understand which treatments are essential in minimizing risks to predation once released. The present study investigates the predation propensity of four mantis species (Phyllocrania paradoxa, Hymenopus coronatus, Blepharopsis mendica, Deroplatys desiccata) and two gecko species (Phelsuma standingi, P. laticauda) on adult Aedes aegypti, Ae. albopictus and Anopheles arabiensis mosquitoes in a laboratory setting. First, any inherent predation preferences regarding mosquito species and sex were evaluated. Subsequently, the effects of chilling, marking, and irradiation, on predation rates were assessed. The selected predators effectively preyed on all mosquito species regardless of the treatment. Predation propensity varied over days for the same individuals and between predator individuals. Overall, there was no impact of laboratory treatments of sterile males on the relative risk of predation by the test predators, unless purposely exposed to double the required sterilizing irradiation dose. Further investigations on standardized predation trials may lead to additional quality control tools for irradiated mosquitoes.
Quality Control Methods for Aedes albopictus Sterile Male Transportation
20392G. D. Mastronikolos, A. Kapranas, G. K. Balatsos, C. Ioannou, D. P. Papachristos, P. G. Milonas, A. Puggioli, I. Pajović, D. Petrić, R. Bellini, A. Michaelakis and N. T. Papadopoulos, Insects, 2022-02-09 09:27:23.
Genetic based mosquito control methods have been gaining ground in recent years for their potential to achieve effective suppression or replacement of vector populations without hampering environments or causing any public health risk. These methods require the mass rearing of the target species in large facilities sized to produce millions of sterile males, as already well established for a number of insects of agricultural importance. Assessing the performance of released males in Sterile Insect Technique (SIT) control programs is of the utmost importance for the success of the operation. Besides the negative effects of mass rearing and sterilization, the handling of sterilized insects and shipment to distant areas may also negatively impact the quality of sterilized males. The aim of the current study was to design and executive quality control (QC) tests for sterilized Aedes albopictus (Asian tiger mosquito) males delivered by air shipment from the mass production facility located in Italy to Greece and Montenegro field release sites. Mass reared mosquito strains were based on biological materials received from Italy, Greece and Montenegro. Tests conducted at the mass rearing facility before transportation revealed a rather high residual female contamination following mechanical sex separation (approximately 1.5% females, regardless of the mosquito strain). Irradiated males of all three mosquito strains induced high levels of sterility to females. Shipment lasting approximately 24 h resulted in approximately 15% mortality, while when shipment lasted nearly two days this increased to almost 40%. The flight ability of sterilized males following one day transportation time was satisfactory (over 60%). The response of sterile males to food and water starvation was comparable and slightly lower than that of wild non-transported males. Longevity of sterile males was shorter than that of wild counterparts and it seems it was not affected by mating to wild females. Both mating propensity and mating competitiveness for wild virgin females was higher for the wild, control males compared to the sterile, transported ones. Overall, the performance of sterile male Ae. albopictus delivered from the mass rearing facility of Italy to Greece in approximately 24 h was satisfactory. Transportation lasting two days or longer incurred detrimental effects on males, which called into question the outcome of the SIT release programs. In conclusion, our results demonstrate the need of quality control procedures, especially when sterile male production facilities are not near to the releasing point. Transportation could be a serious drawback for the implementation of Sterile Insect Releases and, consequently, it is important to establish an efficient and fast transportation of sterilized males in advance.
piggyBac-based transgenic RNAi of serine protease 2 results in male sterility in Hyphantria cunea
20313X. Li, Q. Liu, H. Bi, Y. Wang, X. Xu, W. Sun, Z. Zhang and Y. Huang, Insect Biochemistry and Molecular Biology, 103726. 2022-02-05 08:57:08.
Fall webworm, Hyphantria cunea, is a global invasive forest pest that causes serious damage to the economy and ecosystem of agriculture and forestry. Due to the extent of the problem and the difficulty of conventional chemical control, new technologies must be pursued, such as genetic-based inheritable insect sterile technology (gSIT), which exhibits promise for pest control. In the present study, we established a piggyBac-based transgenic system in fall webworm and generated a dominant male-sterile strain by targeting the seminal fluid protein serine protease 2 (Hcser2), displaying an outstanding trait of gSIT. First, an RNA polymerase type III (Pol III) promoter, the HcU62 small nuclear RNA (snRNA) gene promoter, was identified and characterized through direct injection of RNAi plasmids in vivo. Quantitative real-time PCR revealed that HcU62 had the greatest knockdown efficiency of the Hcyellow gene among five short hairpin RNA (shRNA) plasmids tested, designated HcU61–HcU65. Subsequent application of piggyBac-based transgenic RNAi (HcU62: shHcyellow, Ysh2) significantly reduced the expression level of the Hcyellow gene, resulting in a stable yellow observable phenotype from the larval to pupal stages in Ysh2 transgenic mutants. Finally, an HcU62-driven transgenic RNAi strain targeting the Hcser2 gene was obtained, resulting in a dominant male-sterile phenotype. Significantly, this process did not affect the growth, development, mating behavior or egg laying of the mutants, and the dominant sterile trait could be inherited in the next generation through female Hcser2 mutants. Furthermore, CRISPR/Cas9-mediated disruption of the Hcser2 gene further confirmed the dominant sterile phenotype, supporting it as a generalized target for genetic control of H. cunea. This study reports the first piggyBac-mediated transgenic system in H. cunea, providing a promising genetic method for controlling this pest by targeting Hcser2 gene.
Genetically engineered insects with sex-selection and genetic incompatibility enable population suppression
20286A. Upadhyay, N. R. Feltman, A. Sychla, A. Janzen, S. R. Das, M. Maselko and M. Smanski, eLife, 11. 2022-02-02 11:49:30.
Engineered Genetic Incompatibility (EGI) is a method to create species-like barriers to sexual reproduction. It has applications in pest control that mimic Sterile Insect Technique when only EGI males are released. This can be facilitated by introducing conditional female-lethality to EGI strains to generate a sex-sorting incompatible male system (SSIMS). Here, we demonstrate a proof of concept by combining tetracycline-controlled female lethality constructs with a pyramus-targeting EGI line in the model insect Drosophila melanogaster. We show that both functions (incompatibility and sex-sorting) are robustly maintained in the SSIMS line and that this approach is effective for population suppression in cage experiments. Further we show that SSIMS males remain competitive with wild-type males for reproduction with wild-type females, including at the level of sperm competition.
Could Sterile Aedes albopictus Male Releases Interfere with Aedes aegypti Population in Reunion Island?
20229H. F. Andrianjakarivony, D. Damiens, L. Marquereau, B. Gaudillat, N. Habchi-Hanriot and L.-C. Gouagna, Insects, 13. 2022-01-29 08:58:23.
In Reunion Island, the feasibility of an Aedes albopictus control program using the Sterile Insect Technique (SIT) is studied. Because, in some regions, Ae. albopictus is living in sympatry with Aedes aegypti, the impact of releasing millions of sterile male Ae. albopictus on female Ae. aegypti reproduction needs to be assessed. Thus, to study the potential heterospecific matings, a marking technique using rhodamine B has been used. Rhodamine is given in solution to male mosquitoes to be incorporated into the male body and seminal fluid and transferred during mating into the bursa inseminalis and spermathecae of females. The presence of rhodamine in females occurred in 15% of cases when Ae. aegypti females were offered non-irradiated Ae. albopictus males, 5% when offered irradiated Ae. albopictus males and 18% of cases in the inverse heterospecific matings. Moreover, our results also showed that these matings gave few eggs but were not viable. Finally, the results showed that whatever the type of mating crosses, females in cages previously crossed with males of another species can re-mate with males of their species and produce an equivalent amount of egg compared to females only mated with conspecific males. Despite the promiscuity of the males and females in small cages for three days, heterospecific mating between sterile male Ae. albopictus and female Ae aegypti, 95% of the females have not been inseminated suggesting that in the field the frequency satyrization would be very low.
Self-limiting fall armyworm: a new approach in development for sustainable crop protection and resistance management
20232C. E. Reavey, A. S. Walker, S. P. Joyce, L. Broom, A. Willse, K. Ercit, M. Poletto, Z. H. Barnes, T. Marubbi, B. J. Troczka, D. Treanor, K. Beadle, B. Granville, V. de Mello, J. Teal, E. Sulston, A. Ashton, L. Akilan, N. Naish, O. Stevens, N. Humphreys-Jo, BMC Biotechnology, 22:5. 2022-01-27 09:04:56.
Here, we describe the first germline transformation of the fall armyworm and the development of a genetically engineered male-selecting self-limiting strain, OX5382G, which exhibits complete female mortality in the absence of an additive in the larval diet. Laboratory experiments showed that males of this strain are competitive against wild-type males for copulations with wild-type females, and that the OX5382G self-limiting transgene declines rapidly to extinction in closed populations following the cessation of OX5382G male releases. Population models simulating the release of OX5382G males in tandem with Bt crops and non-Bt ‘refuge’ crops show that OX5382G releases can suppress fall armyworm populations and delay the spread of resistance to insecticidal proteins
Nuclear technique cuts mosquito numbers in Cuban trial
20111M. A. Madsen, IAEA, 2022-01-13 17:14:31.
A pilot trial of a SIT campaign was conducted between April and August 2020 in an area of 50 hectares in El Cano, an isolated neighbourhood of southwest Havana. Arroyo Arenas, another neighbourhood of similar size, was used as an untreated control site. In the pilot trial, almost 1.3 million sterile male mosquitoes were released. Male mosquitos do not carry dengue, bite, nor feed on blood. The IAEA supported Cuba in attaining equipment to separate male and female mosquitoes ahead of irradiation and release and helped equip mosquito rearing facilities. Prior to the trial, Cuba had little capacity in insect rearing and the IAEA supported Cuban fellows to be sent for training on the technique in Brazil, Colombia, Mexico and at the IAEA laboratories in Austria. "Using the SIT for mosquitoes is relatively new anywhere in the world, and pilot trials like this one show how promising they can be," said Rui Cardoso Pereira, Head of the Insect Pest Control Section at the Joint FAO/IAEA Centre of Nuclear Techniques for Food and Agriculture.
Effects of Sterile Males and Fertility of Infected Mosquitoes on Mosquito-Borne Disease Dynamics
20097X. L. Sun, S. Q. Liu, Y. F. Lv and Y. Z. Pei, Bulletin of Mathematical Biology, 84:33. 2022-01-13 09:37:31.
By studying an infection-age structured model, we consider the effects of releasing sterile males and the fertility of infected mosquitoes on the mosquito-borne diseases transmission including the extinction of mosquitoes, the elimination and persistence of diseases. Firstly, equivalent integral equations are established to prove the well-posedness of solutions. Then, the main results of disease dynamics are given. By taking chikungunya as a numerical simulation example, an optimal releasing threshold is given according to our presupposed control standard. When the fertility disturbance of infected mosquitoes is small, the high releasing amount plays a main role on the control of the disease; however, when the fertility disturbance is large, the initial distributions and the fertility of infected mosquitoes are the key factors to control the disease. Mathematically, the fertility of infected mosquitoes makes the system have complex dynamics with multiple positive equilibria and bistability.
The prince, the mayor, and the U.S. fish that ate Japan
20103C. Elliot, National Geographic, 2022-01-11 16:44:32.
When Crown Prince Akihito visited Chicago on October 3, 1960, his sole request was to visit Shedd Aquarium. Then Mayor Richard J. Daley, an avid angler, presented the prince with a gift that he scooped with a net from one of the tanks himself: 18 bluegills, the official Illinois state fish. The 26-year-old future emperor was already a passionate ichthyologist, and he planned to stock the exotic fish in the moat surrounding his palace, according to accounts in the Chicago Tribune at the time. At windy Chicago O’Hare International Airport the next day with Princess Michiko, Akihito bid the city farewell, carrying a gift that he couldn’t have imagined would cause a decades-long ecological crisis in his homeland. In the intervening six decades, the bluegills became an invasive, species-destroying nightmare, crowding Japanese freshwater lakes and rivers and destroying native fish biodiversity, says Kenji Saitoh, a researcher at the country’s Fisheries Resources and Education Agency. Fortunately, science has marched on in 60 years. Now, Japanese geneticists are experimenting with the gene editing wizardry of CRISPR to sterilize the invasive bluegills. If the initiative succeeds, wildlife managers could use the same technique to rid the U.S. of damaging aquatic invasives such as the Asian carp.
Introgression of the Aedes aegypti red-eye genetic sexing strains into different genomic backgrounds for sterile insect technique applications
20137A. A. Augustinos , K. Nikolouli , L. D. De La Fuente , M. Misbah-Ul-Haq, D. O. Carvalho and K. Bourtzis, Frontiers in Bioengineering and Biotechnology, 2022-01-11 13:16:31.
Aedes aegypti is an invasive mosquito species and major vector of human arboviruses. A wide variety of control methods have been employed to combat mosquito populations. One of them is the sterile insect technique (SIT) that has recently attracted considerable research efforts due to its proven record of success and the absence of harmful environmental footprints. The efficiency and cost-effectiveness of SIT is significantly enhanced by male-only releases. For mosquito SIT, male-only releases are ideally needed since females bite, blood-feed, and transmit the pathogens. Ae. aegypti genetic sexing strains (GSS) have recently become available and are based on eye color mutations that were chosen as selectable markers. These genetic sexing strains were developed through classical genetics and it was shown to be subjected to genetic recombination, a phenomenon that is not suppressed in males as is the case in many Diptera. The genetic stability of these GSS was strengthened by the induction and isolation of radiation-induced inversions. In this study, we used the red eye mutation and the inversion Inv35 line of the Ae. aegypti red-eye GSS s and introgressed them in six different genomic backgrounds to develop GSS with the respective local genomic backgrounds. Our goal was to assess whether the recombination frequencies in the strains with and without the inversion are affected by the different genomic backgrounds. In all cases the recombination events were suppressed in all Inv35 GSS strains, thus indicating that the genomic background does not negatively affect the inversion result. The absence of any effect that could be ascribed to genetic differences, enables the introgression of the key elements of the GSS into the local genomic background prior to release to the target areas. Maintaining the local background increases the chances for successful matings between released males and wild females and addresses potential regulatory concerns regarding biosafety and biosecurity.
Integrated control of Aedes albopictus in Southwest Germany supported by the Sterile Insect Technique
20046N. Becker, S. M. Langentepe-Kong, A. T. Rodriguez, T. T. Oo, D. Reichle, R. Luhken, J. Schmidt-Chanasit, P. Luthy, A. Puggioli and R. Bellini, Parasites and Vectors, 15:19. 2022-01-05 10:11:20.
Background: The invasive species Aedes albopictus, commonly known as the Asian tiger mosquito, has undergone extreme range expansion by means of steady introductions as blind passengers in vehicles traveling from the Mediterranean to south-west Germany. The more than 25 established populations in the State of Baden-Wurttemberg, Palatine and Hesse (south-west Germany) have become a major nuisance and public health threat. Aedes albopictus deserves special attention as a vector of arboviruses, including dengue, chikungunya and Zika viruses. In Germany, Ae. albopictus control programs are implemented by local communities under the auspices of health departments and regulatory offices. Methods: The control strategy comprised three pillars: (i) community participation (CP) based on the elimination of breeding sites or improved environmental sanitation, using fizzy tablets based on Bacillus thuringiensis israelensis (fizzy Bti tablets; Culinex (R) Tab plus); (ii) door-to-door (DtD) control by trained staff through the application of high doses of a water-dispersible Bti granular formulation (Vectobac (R) WG) aimed at achieving a long-lasting killing effect; and (iii) implementation of the sterile insect technique (SIT) to eliminate remaining Ae. albopictus populations. Prior to initiating large-scale city-wide treatments on a routine basis, the efficacy of the three elements was evaluated in laboratory and semi-field trials. Special emphasis was given to the mass release of sterile Ae. albopictus males. Results: More than 60% of the local residents actively participated in the first pillar (CP) of the large-scale control program. The most effective element of the program was found to be the DtD intervention, including the application of Vectobac (R) WG (3000 ITU/mg) to potential breeding sites (10 g per rainwater container, maximum of 200 I = maximum of approx. 150,000 ITU/I, and 2.5 g per container <50 I) with a persistence of at least 3 weeks. In Ludwigshafen, larval source management resulted in a Container Index for Ae. albopictus of < 1% in 2020 compared to 10.9% in 2019. The mean number of Aedes eggs per ovitrap per 2 weeks was 4.4 in Ludwigshafen, 18.2 in Metzgergrun (Freiburg) (SIT area) and 22.4 in the control area in Gartenstadt (Freiburg). The strong reduction of the Ae. albopictus population by Bti application was followed by weekly releases of 1013 (Ludwigshafen) and 2320 (Freiburg) sterile Ae. albopictus males per hectare from May until October, resulting in a high percentage of sterile eggs. In the trial areas of Ludwigshafen and Frieburg, egg sterility reached 84.7 +/- 12.5% and 62.7 +/- 25.8%, respectively; in comparison, the natural sterility in the control area was 14.6 +/- 7.3%. The field results were in line with data obtained in cage tests under laboratory conditions where sterility rates were 87.5 +/- 9.2% after wild females mated with sterile males; in comparison, the sterility of eggs laid by females mated with unirradiated males was only 3.3 +/- 2.8%. The overall egg sterility of about 84% in Ludwigshafen indicates that our goal to almost eradicate the Ae. albopictus population could be achieved. The time for inspection and treatment of a single property ranged from 19 to 26 min depending on the experience of the team and costs 6-8 euros per property. Conclusions: It is shown that an integrated control program based on a strict monitoring scheme can be most effective when it comprises three components, namely CP, DtD intervention that includes long-lasting Bti-larviciding to strongly reduce Ae. albopictus populations and SIT to reduce the remaining Ae. albopictus population to a minimum or even to eradicate it. The combined use of Bti and SIT is the most effective and selective tool against Ae. albopictus, one of the most dangerous mosquito vector species.
Intervention of Modern Genetic Tools for Managing Insect Pests of Fruit Crops
25476G. S. Miglani, S. Singh, Z. Li and R. K. Sandhu, Genetic Methods and Tools for Managing Crop Pests, 2022-01-01 09:00:36.
Merits and demerits of select modern genetic tools as sterile insect technique, repressible dominant lethal, engineering insect pests, transgenic crops, primary resistance management, gene silencing RNA interference, genome-editing-based methods, autocidal insect control techniques, and genomics approaches for pest management have been discussed. Application of these methods to manage insect pests of fruit crops have been dealt with. Finally, new vision to pest control and future prospects in the utilization of molecular genetics-based tools for insect pest management has been presented.
Temporal Viability of Aedes aegypti and Aedes albopictus Eggs Using Two Hygroscopic Substances as Preservatives under a Sterile Insect Technique (SIT) Program in Southern Mexico
19721E. N. Martínez-García, E. E. Díaz-González, C. F. Marina, J. G. Bond, J. J. Rodríguez-Rojas, G. Ponce-García, R. M. Sánchez-Casas and I. Fernández-Salas, Insects, 13. 2021-12-21 12:31:48.
Dengue and other Aedes-borne diseases have dramatically increased over the last decades. The Sterile Insect Technique (SIT) has been successfully used as part of integrated pest strategies to control populations of insect-plant and livestock pests and is currently being tested as a potential method to reduce mosquito populations in an environmentally friendly approach. However, during the mass rearing steps needed to produce millions of mosquitoes, egg storage and preservation are essential for a certain amount of time. Eggs of Aedes aegypti have a chorionic pad that functions as a sticky substance to glue them onto the inner walls of larval breeding sites. The chorionic pad is chemically made of hyaluronic acid, a hygroscopic compound, responsible to protect them from desiccation over time. Two commercial products with hygroscopic properties, hydrolyzed collagen, and Hyalurosmooth®, both were tested to assess their ability to prolong egg life storage for A. aegypti and A. albopictus. Results showed that 85–95% of Ae. aegypti eggs were able to hatch up to week 8 after being treated with both hydrophilic compounds, compared with the control 66.3%. These two substances showed promising effects for keeping Ae. aegypti eggs viable during prolonged storage in mass rearing insect production focused on vector control SIT programs.
Three Decades of Malaria Vector Control in Sudan: The Plausible Role of Sterile Insect Technique (SIT)
19977A. Elaagip and A. Adedapo, Genetically Modified and other Innovative Vector Control Technologies, 2021-12-21 11:51:34.
In Northern State, Sudan, a feasibility study for sterile insect technique (SIT) in an area-wide integrated pest management was established for the first time in an African country. The aim of the study was to see whether it is feasible, from a technical, an economical and a biological perspective, to use sterile male mosquitoes to control mosquito populations in designated areas in the African context. The project was focussed on Anopheles arabiensis, one of the major malaria vectors. Meteorological data, larval surveillance and population genetic studies were carried out on the disease vectors. The first phase of the study focussed on the development of an efficient sex-separation system, development of dose-sterility curves for the pupal and adult stages and testing of a range of doses in competition experiments to determine effective sterility dose. This stage was followed by a semi-field phase that monitored their swarming and mating behaviours, effectiveness of irradiated males in competitive experiments with wild males and insemination rates. Information regarding irradiation and transportation of irradiated males were also obtained during the study. Unfortunately, the SIT study was terminated in 2017 before starting field release of irradiated males. In spite of the challenges, such investment need not be totally abandoned as valuable experience has been gained and capacity built, which are of high value to malaria control program in Sudan.
Perspectives into Genetic Manipulations for Control of Dengue Vector (Aedes aegypti Linnaeus, 1762) with Reference to Progress in Indian Experiments
19975R. Chatterjee, S. Bhattacharya and B. K. Tyagi, Genetically Modified and other Innovative Vector Control Technologies, 2021-12-21 11:46:45.
Vector-borne diseases like malaria, dengue, chikungunya, Japanese encephalitis, Zika and others claim millions of lives across the globe annually, and as such their control has become an ardent necessity. Past attempts over the decades have introduced vector control through chemical, biological and environmental means. However, these measures, already in place, failed to completely bring down the mortality rates from vector-borne diseases, most of which lack a vaccine to prevent epidemics or even a specific antidote to treat patients. The modern development of technologies such as the release of insects carrying a dominant lethal (RIDL) gene system, an example of transgenesis; the Wolbachia-based cytoplasmic incompatibility inducing infertility in female insects, an example of paratransgenesis; and the revolutionary gene drive (CRISPR/Cas9) technology, has their roots in the sterile insect technology (SIT), which worked by creating sterilized males through irradiation to compete with their wild counterparts and subsequently mate with females in nature to produce infertile eggs; a technology meant to gradually and finally exterminate the vector population in nature. These technologies have shown great promise, albeit many imperfections, particularly regarding acceptance by the concerned societies. As far as vector control is concerned, we have attempted to simplify their definitions for the common man so that the intricate scientific jargon about these technologies do not instill any fear or doubts to the end users.
Aedes Control Using Sterile Insect Technique (SIT) in Malaysia
19973W. A. Nazni, G.-N. Teoh, S. I. Shaikh Norman Hakimi, M. A. Muhammad Arif, M. Tanusshni, M. A. Nuradila, A. Nurfarahin Hanini, I. A. Shazia, A.-M. Tan, H. Rabizah, M. D. Ahmad Zainuri, A. Hasnor Hadi, Y.-L. Cheong, A. Norazah, H. Maiga, R. S. Lees and L. H, Genetically Modified and other Innovative Vector Control Technologies, 2021-12-21 11:41:43.
The continued occurrence of massive outbreaks of Aedes-borne viral diseases of dengue, chikungunya, Zika and yellow fever, in spite of intensive and extensive application of conventional control measures, necessitates application of new tools, such as sterile insect technique (SIT), to stem the tide. Sterile insect technique is a form of biological control method, whereby sterile male insects are released in overwhelming numbers in the wild. These sterile males compete with the wild males to mate with the wild females. The females mated with sterile males will produce sterile eggs that will not hatch. Sustained release of sterile males over a period of time will lead to suppression or elimination of the natural population. Sterility is induced by gamma ray from the radioisotope of cobalt-60 and cesium-137 or X-ray. SIT is safe, cost-effective and environmentally non-polluting, and insects are unable to develop resistance to this method. SIT has a strong track record of success in elimination of agricultural pests, and this led to increased interest in using SIT against mosquitoes of public health importance. Studies and trials against Aedes were conducted in the 1960s and, more recently, against Ae. albopictus with promising results. Attempts were also made to apply SIT for the control of Aedes in several countries. Malaysia’s first experience with SIT was in the 1990s, when the Malaysian Nuclear Agency teamed with the MARDI and local universities to sterilise an agricultural pest, the diamondback moth. To prepare for the possible threat of introducing the Old World screw worm (Chrysomya bezziana) into Australia from neighbouring countries, from 1995 to 2000, Australia and Malaysia undertook a collaborative myiasis control research project located at the Institut Haiwan, Kluang, Malaysia. The project assisted in suppression trials of the screw worm in Malaysia and supported research that developed and evaluated improved Old World screw worm suppression and eradication techniques. In 2014, in collaboration with the Malaysian Nuclear Agency, the IMR conducted preliminary studies to determine the optimum sterilising dose of gamma irradiation against Ae. aegypti. In addition, the impact of sterilisation on the biological parameters of Ae. aegypti was also determined. The most effective sterilising dose that did not adversely affect the male was determined to be 55 Gy. Subsequently, a new initiative of field release of sterile Aedes aegypti males for the control of dengue was initiated in 2019. This 2-year programme will aim to release gamma ray-sterilised Ae. aegypti males in three trial sites to reduce the natural mosquito population to a level below the threshold required for dengue transmission. To ensure public acceptance, public engagement, a prerequisite for a successful release programme, will be conducted intensively prior to the release.
Genetic Improvements to the Sterile Insect Technique (SIT) for the Control of Mosquito Population
19927P. V. D. Dilani, Y. I. N. S. Gunawardene and R. S. Dassanayake, Genetically Modified and other Innovative Vector Control Technologies, 2021-12-21 09:33:58.
Mosquito-borne diseases are becoming a major health problem worldwide. At present, the principal method of controlling these diseases entirely depends on the mosquito vector control strategies. However, traditional control methods which are focussed on reducing mosquito populations through environmental management and the application of insecticides are largely ineffective. Hence, various control methods, including the release of sterile insect technique (SIT), have been proposed for the reduction of the mosquito population. As a species-specific control strategy, SIT offers considerable environmental benefits and a chemical-free option for insect control. However, the application of the SIT to mosquito control consistently suffered from lack of efficient sexing system, high fitness cost and operational difficulty in ionizing radiation, density-dependent nature of the target mosquito population and various other technical issues. The intervention of genetic engineering has led to several improvements in the operation or security of SIT programmes. The advent of mosquito transgenesis has paved the way for novel approaches in mosquito control. One possibility is a release of insects carrying dominant lethal (RIDL) strategy by engineering self-limiting gene, which offers solutions for many drawbacks of traditional SIT by providing genetic sterilization, genetic sexing, genetic containment and provision of genetic markers while maintaining its environmentally benign and species-specific utility. The success of this strategy often depends on how genetic modification affects the fitness of the mosquitoes. With several improvements and modifications allowing minimum fitness load, RIDL is now available for a wide range of mosquitoes such as Aedes aegypti, Aedes albopictus and Anopheles stephensi with field-testing possibilities. However, with solid epidemiological evidence and community support, widespread implementation of these strategies might reverse the current alarming global mosquito vector-borne diseases.
Field Trials of Gene Drive Mosquitoes: Lessons from Releases of Genetically Sterile Males and Wolbachia-infected Mosquitoes
19925J. M. Marshall and V. N. Vásquez, Genetically Modified and other Innovative Vector Control Technologies, 2021-12-21 09:27:08.
The discovery of CRISPR-based gene editing and its application to homing-based gene drive has been greeted with excitement, for its potential to control mosquito-borne diseases on a wide scale, and concern, for the invasiveness and potential irreversibility of a release. At the same time, CRISPR-based gene editing has enabled a range of self-limiting gene drive systems to be engineered with much greater ease, including (1) threshold-dependent systems, which tend to spread only when introduced above a certain threshold population frequency, and (2) temporally self-limiting systems, which display transient drive activity before being eliminated by virtue of a fitness cost. As these CRISPR-based gene drive systems are yet to be field-tested, plenty of open questions remain to be addressed, and insights can be gained from precedents set by field trials of other novel genetics-based and biological control systems, such as trials of Wolbachia-transfected mosquitoes, intended for either population replacement or suppression, and trials of genetically sterile male mosquitoes, either using the RIDL system (release of insects carrying a dominant lethal gene) or irradiation. We discuss lessons learned from these field trials and implications for a phased exploration of gene drive technology, including homing-based gene drive, chromosomal translocations, and split gene drive as a system potentially suitable for an intermediate release.
Arthropods of Medical Importance: Need for Genetic and Other Innovative Vector Control Technologies, with Emphasis on Eco-biosocial and Environmental Considerations.
19923B. K. Tyagi, Genetically Modified and other Innovative Vector Control Technologies, 2021-12-21 09:22:08.
Among the world’s known vector groups, viz. arthropods, snails and rodents, the most important vectors originate from arthropods, the jointed legs. Arthropods are doubtlessly regarded as the most dominant creatures on the Earth due largely to their remarkable structural and behavioural diversity, besides humongous species preponderance. Of course, some of these arthropods are serious pests and/or vectors of human and animal diseases—deadly, debilitating and economy destructing. According to an estimate, arthropod species make approximately 80% of the global biological diversity. Born some 350–400 million years ago, they have of course achieved, to the utter envy of all other animal forms, a formidable genetic diversity and robustness so much so that they have virtually captivated pivotal human attention for centuries. They serve as a spectacular model of bioprospecting or laboratory experiments mostly because they are found in abundance, breed prodigiously and are exceptionally easier to culture or cultivate. For the aforesaid reasons, arthropods are also the easy target for genetic manipulations such as the transgenesis (using the release of insect carrying dominant lethal (RIDL) gene system or gene drive-based genome editing, e.g. CRISPR/Cas9, to suppress or replace the vector population) or paratransgenesis (e.g. deploying endosymbiont Wolbachia-induced cytoplasmic incompatibility for replacing natural vector population). In particular, the advent of CRISPR technology has excited the potential to engineer new game-changing technologies and innovative systems that can be used to control wild populations of mosquitoes. Two developments of particular interest are a self-limiting system termed precision-guided sterile insect technique (pgSIT) and a homing-based gene drive (HGD). The unique features of these systems can make them valuable tools to control vector mosquitoes in the future. All these biotechnological advancements in vector control are designed to fit well in the multi-methodical integrated vector management (IVM) strategy.
Genetically Modified and other Innovative Vector Control Technologies
19912B. K. Tyagi, SpringerLink, 2021-12-21 08:48:19.
This book comprehensively covers the latest development in developing and deploying the genetically modified vectors, particularly Anopheles and Aedes mosquitoes responsible for transmitting malaria parasites and dengue viruses, the most deadly and/or debilitating among all the vector-borne diseases. It is considered timely and commensurate to bring about a book dealing with the various ecological, biological and social as well as regulatory aspects for the deployment of genetically modified vectors in special context with the biosafety of humans, his associates, and the environment. Written by an array of specialists and experts in various subjects of genetically modified organisms, this book centrally addresses the (i) basic principles of the genetic manipulation of vectors and they are potential impact on human and the environment, (ii) ecological, biological, ethical, legal and social implications of the use of genetically modified vectors, (iii) identification of potential hazards; assessment and management of risks for human and environment; risk/benefit analysis, (iv) principles and practices for the assessment and management of biosecurity and biosafety in laboratories (and in the field), (v) guiding principles for creation and management of institutional or national biosafety review boards and ethics review committees, and (vi) development and application of a biosafety regulatory framework and its related legal principles at national levels for securing the development and use of vector control methods based on genetic modification strategies.
Oxitec wraps mosquito trials for the season
19698T. O'Hara, Keynews.com, 2021-12-15 19:12:16.
The private bio-tech company Oxitec has wrapped up its test release of genetically modified mosquitoes in the Florida Keys
Genetic Control in Historical Perspective: The Legacy of India’s Genetic Control of Mosquitoes Unit
19652R. Wilbanks, Hastings Center Report, 51:S11-S18. 2021-12-14 18:54:15.
Abstract In the early 1970s, a World Health Organization-initiated and United States-funded project released lab-reared mosquitoes outside New Delhi in the first large-scale field trials of the genetic control of mosquitoes. Despite partnering with the Indian Council of Medical Research and investing significantly in outreach to local communities at the release sites, the project was embroiled in controversy and became an object of vehement debate within the Indian parliament and diplomatic contretemps between the United States and India. This early episode of genetic control research demonstrates how a scientific collaboration was entangled in geopolitics and shaped by the legacy of colonialism. This historical case study has implications for public deliberation in the present, pointing to the challenges of shared decision-making in the context of structural inequality, the way that a backdrop of military interest in a technology can impede trust, and the long-term consequences of projects that foster mistrust.
How Israelis help the world fight mosquito-borne diseases
19690A. K. Leichman, ISRAEL21c, 2021-12-14 18:22:37.
Israeli scientists and entrepreneurs understand the problems and risks and have been developing a series of ingenious remedies to this growing problem. Prof. Philippos Aris Papathanos, head of Hebrew University’s Insect Genetics Lab, was awarded a Bill & Melinda Gates Foundation grant to develop new genetic approaches for controlling malaria mosquito populations. “We’re building a modern variant of an old idea that has been around since the 1950s: to control mosquitoes by modifying and manipulating their genetics,” Papathanos tells ISRAEL21c. He explains that sterilizing and releasing individual male mosquitoes theoretically leads to the collapse of the population. But this tactic has proven difficult to upscale to the necessary level of a whole city, country or continent. Instead of sterilization, Papathanos’ lab is using cutting-edge CRISPR technology to modify male malaria mosquitoes’ Y chromosome so that they produce only male babies, and those sons inherit the altered chromosome. Over time, there will be no more females and hence no more disease-transmitting bites.“This method can suppress the population in a stronger way because the genes are designed to spread through the population. We don’t need to upscale if we make the system more efficient with the least number of insects released,” says Papathanos.
No, genetically engineered mosquitoes aren’t about to be released in Berkeley
19619K. D. Rauch, Berkeleyside, 2021-12-13 21:34:24.
Judith Pierce, public outreach coordinator for the Alameda County Mosquito Abatement District, would like to make one thing clear: A release of genetically engineered mosquitoes is not coming to Berkeley — or anywhere in Alameda County — in the near future. Not to her knowledge, anyway, and if it were official, she would know. The Berkeley City Council’s robust discussion of this at a council meeting in early November was based partially on misleading information, said Pierce.The council, at its Nov. 9 meeting, considered whether to send a letter to the Environmental Protection Agency (EPA) opposing a potential California pilot study of mosquitoes engineered to combat Zika, dengue, chikungunya, yellow fever and other diseases.Councilmember Ben Bartlett sponsored the item, sending out an email to constituents ahead of time urging them to take action to prevent the EPA from “releasing billions of genetically engineered mosquitoes across California, specifically in Alameda County.” The sample letter Bartlett presented to the council was focused statewide, but background information he shared, as well as discussion at the meeting, focused on keeping the mosquitoes out of the county.
In Real Life: GMOsquitoes
19544Newsy, 2021-12-06 20:41:41.
The release of genetically modified mosquitoes in Florida gives hope of reducing the spread of disease while causing concerns among some citizens.
The economic value of genetically engineered mosquitoes as a Malaria control strategy depends on local transmission rates
19788K. Lacy, K. A. Schaefer, D. P. Scheitrum and E. Y. Klein, Biotechnology Journal, 10. 2021-12-06 14:26:13.
This paper assesses the economic value of genetically engineered (GE) Anopheles gambiae mosquitoes as a malaria control strategy. We use an epidemiological-economic model of malaria transmission to evaluate this technology for a range of village-level transmission settings. In each setting, we evaluate public health outcomes following introduction of GE mosquitoes relative to a "status quo" baseline scenario. We also assess results both in contrast to-and in combination with-a Mass Drug Administration (MDA) strategy. We find that-in low transmission settings-the present value (PV) public health benefits of GE mosquito release are substantial, both relative to status quo dynamics and MDA. In contrast, in high transmission settings, the release of GE mosquitoes may increase steady-state infection rates. Our results indicate that there are substantial policy complementarities when GE mosquito release is combined with local MDA-the combined control strategy can lead to local eradication.
New molecular genetic techniques: regulatory and societal considerations
19403Nielsen, K. M., AREA-WIDE INTEGRATED PEST MANAGEMENT: Development and Field Application, 2021-11-29 18:07:46.
A rapidly expanding toolbox of techniques available for genome editing provides the basis for a new continuum in types of modifications that can be introduced into a genome and blur the bimodal GMO vs. non-GMO (genetically modified organism) divide. Site-directed nucleases (SDN) are now used to modify existing nucleotides within genomes instead of adding recombined DNA as transgenes. Moreover, new gene drive approaches are in development based on SDNs. A number of potential drive applications have been reported, but uncertainties in trait stability and limitations in knowledge of the affected system at various temporal and spatial levels slow down their current uses. Adoption of new genome targeted technology takes place in a social context. The context will vary between countries and cultures, expressed in values, ethics, politics and priorities - that are translated into different regulatory approaches. Some developed products using new genome editing techniques clearly fall under internationally negotiated regulations of GMOs. However, other product outcomes of editing techniques challenge our current understanding and definition of GMOs. There is an urgent need for further research, for building international consensus and harmonizing regulatory approaches to facilitate categorization, predictability, transparency, trust and trade.
Area-wide management of fruit flies in a tropical mango growing area integrating the sterile insect technique and biological control: From a research to an operational programme
19391Liedo, P., Montoya, P. , and Toledo, J., AREA-WIDE INTEGRATED PEST MANAGEMENT: Development and Field Application, 2021-11-29 17:29:33.
The Sterile Insect Technique (SIT) has been successfully used for the control of fruit flies in a number of places in the world. One requirement for its successful application is that wild populations should be at low densities to achieve effective sterile to wild fly overflooding ratios. This has been an important reason that has limited its integration in fruit fly management in tropical fruit growing areas, where climate conditions and the availability of hosts all year-round results in high population densities. Here we report the results of a project where SIT integration into fruit fly management was evaluated under the tropical conditions of the mango growing area in the Soconusco region of Chiapas, Mexico. The basis for the area-wide integrated pest management (AW-IPM) approach was the knowledge of the population dynamics of the pest fruit flies in the region and of the fruit phenology. The main commercial mango growing areas are in the lowlands, where fruit fly populations are very low outside of the mango production season. Population densities are higher in the midlands and highlands, where alternate hosts are common in backyards and as part of the natural vegetation. We call these refuge areas, and the AW-IPM approach aimed at establishing a biological barrier with releases of parasitoids and sterile male fruit flies to suppress the fruit fly populations and prevent or minimize the dispersal of wild flies from the refuge areas to the mango orchards. In 2014, after two years of releases, fruit fly population densities were suppressed more than 70% in the release area and 65% in the entire area, including the lowlands with the mango orchards. With the support of fruit growers, state and federal governments, this project was continued and established as an operational AW-IPM programme. In 2016, after 4 years of programme implementation, the detection of wild flies was significantly reduced, and the number of batches of fruit that were rejected at the packing houses due to the detection of infested fruits was the lowest in the past 12 years, since the recording of these data was initiated. These indicators declined even further in 2017. The results obtained demonstrate that AW-IPM integrating the SIT can be applied successfully against fruit flies under tropical conditions with naturally high pest densities, providing there is adequate knowledge on the population dynamics of the fruit fly species present in the region.
AREA-WIDE INTEGRATED PEST MANAGEMENT: Development and Field Application
19371Hendrichs, J. Pereira, R., Vreysen, M. J. B., AREA-WIDE INTEGRATED PEST MANAGEMENT: Development and Field Application, 2021-11-29 17:04:54.
The concept of area-wide integrated pest management (AW-IPM), in which the total population of a pest in an area is targeted, is central to the effective control of such populations through the integration of genetic, biological and other pest suppression technologies. Insect movement, occurring sometimes over long distances, is generally underestimated. As a consequence, most conventional pest management is implemented as a localized or field-by-field, un-coordinated action against segments of a pest population, not taking in consideration insect movement, resulting very often in an unsustainable spiral of insecticide application and eventual resistance of the pest against the used insecticides. On the other hand, an AW-IPM approach adopts a preventive rather than a reactive strategy, whereby all individuals of the pest population are targeted in time and space and selecting a time when the pest populations are more vulnerable (e.g. during certain times of the year when the population densities are naturally low), requiring in the longer term fewer inputs and resulting in more cost-effective and sustainable pest management. It involves a coordinated effort over often larger areas, including not only agricultural, but also natural and other areas with pest presence. By addressing these sources of reinfestation in the surroundings of the agricultural areas, satisfactory pest control is achieved in the whole area and fewer control actions are required. This new textbook on AW-IPM assembles a series of selected papers that attempts to address various fundamental components of AW-IPM, e.g. the importance of relevant problem-solving research, the need for essential baseline data, the significance of integrating adequate tools for appropriate control strategies, and the value of pilot trials, etc. Of special interest are the numerous papers on pilot and operational programmes that pay special attention to practical problems encountered during the implementation of insect pest control programmes. A significant number of contributions to this book resulted from oral and poster presentations at the Third FAO/IAEA International Conference on “Area-wide Management of Insect Pests: Integrating the Sterile Insect and Related Nuclear and Other Techniques”, which was successfully held from 22-26 May 2017 at the Vienna International Centre, Vienna, Austria. The conference was attended by 360 delegates from 81 countries and six international organization. However, the book contributions were selected beyond the work presented at the conference and a number of experts dealing mainly with action programmes were invited to present their work in this publication
Combined sterile insect technique and incompatible insect technique: concept, study design, experience and lessons learned from a pilot suppression trial in Thailand
19367Kittayapong, P., AREA-WIDE INTEGRATED PEST MANAGEMENT: Development and Field Application, 2021-11-29 16:50:12.
Climate change, rapid global transport and land use change leading to urbanization and agricultural intensification have facilitated disease emergence in vulnerable regions like Southeast Asia, and also the global expansion of vectors and vector-borne diseases into other regions like the Americas and Europe. Important vector-borne diseases, i.e. dengue, chikungunya, yellow fever, and Zika are transmitted by the major mosquito vector species, Aedes aegypti (L.) and Aedes albopictus (Skuse). Management of Ae. aegypti populations in countries endemic to these diseases, especially in Southeast Asia, is not sufficiently effective, resulting in high morbidity and mortality in the region. Insecticide resistance has become an important issue, causing failure in insecticide-based vector control. Innovative or alternative tools/approaches are needed to effectively reduce mosquito vector populations and consequently reduce the diseases they transmit. A trial integrating the environment-friendly Sterile Insect Technique (SIT) and the insect incompatible technique (IIT) was successfully carried out on a small-scale in a semi-rural setting in Thailand. In this chapter, we report on the design and methodology, as well as the experience and lessons learned from the baseline preparation and implementation of the pilot trial.
Barriers and facilitators of area-wide management including sterile insect technique application: The example of Queensland fruit fly
19365Mankad, A., Loechel, B., and Measham, P. F., AREA-WIDE INTEGRATED PEST MANAGEMENT: Development and Field Application, 2021-11-29 16:44:16.
The area-wide management (AWM) of highly mobile insect pests such as tephritid fruit flies requires an integrated understanding of technical, social and institutional processes that drive a coordinated approach within a defined area. Furthermore, the success of an AWM programme is dependent upon the coordinated efforts of key stakeholders within the designated area (e.g. growers, community members). Yet, public views regarding AWM may not reflect those views held by scientists or stakeholders. Public considerations for acceptance are likely varied and multidimensional. A series of qualitative (phases 1-2) and quantitative (phase 3) studies examined stakeholder and community attitudes towards AWM to manage Queensland fruit fly Bactrocera tryoni (Froggatt) (Tephritidae) and the novel use of the Sterile Insect Technique (SIT) as a possible component of AWM. Research was conducted over three regions of varying pest prevalence, ranging from zero to endemic; participants included growers, extension officers, industry and government representatives, and members of the general public. Participants in this research were asked to consider potential barriers and facilitators to the widespread uptake of AWM integrating the SIT, including any relevant institutional-level factors. Combined data revealed potential social barriers to AWM and SIT uptake. Most notably, there were perceptions of low efficacy in successfully coordinating key social groups for the purposes of an AW-IPM approach, and a concern for the possibility of 'free-riders' within an areawide system. On the other hand, innovation complexity and observability of outcomes were important factors contributing to acceptance of AWM. Importantly, all participants were influenced by the attitudes and behaviours of important others. Participants also identified key facilitators that could assist in the uptake of AWM using the SIT. These facilitators include the importance of trustworthy information sources and harnessing the persuasive influence of community champions and central packing houses on commercial growers. Overall, there was high stated acceptance for the SIT, both on-farm and in towns, as long as SIT application was found to be economically feasible at individual farm or household level and the community was adequately consulted.
Putting the sterile insect technique into the modern integrated pest management toolbox to control the codling moth in Canada
19363Nelson, C., Esch, E., Kimmie, S., Tesche, M., and Philip, H. Arthur, S., AREA-WIDE INTEGRATED PEST MANAGEMENT: Development and Field Application, 2021-11-29 16:38:40.
The Okanagan-Kootenay Sterile Insect Release (OKSIR) programme, in southern British Columbia, Canada, has been successfully applying the Sterile Insect Technique (SIT) as part of a sustainable areawide integrated pest management (AW-IPM) programme to control the codling moth Cydia pomonella L. in pome fruits in the region for over 20 years. Chemical, cultural and biological techniques that complement the SIT are also integrated into orchard and regional pest management plans by the programme and/or individual growers. The AW-IPM programme is supported by close monitoring of codling moth populations in orchards and adjacent urban properties; enforcing suppression of codling moth infestations in orchards and urban areas; removing derelict orchards, wild host trees and poorly managed host trees; and increasing public awareness and education. Successful collaboration between the OKSIR programme, the pome fruit industry, area residents and various government organizations has reduced codling moth populations by 94%, relative to pre-programme levels, and codling moth damage to less than 0.2% of fruit, in more than 90% of the orchards in the programme area. Local pesticide sales indicate a 96% reduction in the amount of active ingredient used against the codling moth since 1991. Implementing the SIT through an innovative social approach to local community-centred area-wide pest management has posed many challenges and created many learning opportunities. The codling moth mass-rearing facility in Osoyoos, British Columbia, has the capacity to produce 780 million sterile codling moths annually, but only a portion of that is used seasonally to treat 3400 hectares (ha) of pome fruit made up of small orchards intermixed with residential areas in the Okanagan Valley. As a result of climate change and increasing global trade, destructive insect pests are migrating to new habitats throughout the world. These new threats must be managed in ways that protect both the agrifood industries and the natural environments in which the industries operate. The OKSIR programme is an effective and easily transferred model to meet these challenges, especially as a supplement to other biological control methods. The programme is also a compelling model of success that can encourage other regions to use the SIT in their pest management toolbox to combat codling moth infestations across multiple local community jurisdictions using environment-friendly, cost-effective methods based on proven technology. The OKSIR programme is exploring the sale of surplus sterile moths, egg sheets or possible virus production as an opportunity to offset costs of incorporating additional area-wide approaches to combat other invasive pests.
Ecology, behaviour and area-wide control of the floodwater mosquito Aedes sticticus, with potential of future integration of the sterile insect technique
19361Lundstrom, J. O. Schafer, M. L. Kittayapong, P., AREA-WIDE INTEGRATED PEST MANAGEMENT: Development and Field Application, 2021-11-29 16:33:24.
The strategy of aerial control of the floodwater mosquito Aedes sticticus (Meigen) in the floodplains of River Dalalven, central Sweden, was developed to directly address specific larval breeding areas in temporary flooded wet meadows and swamps. Using the Bti-based larvicide VectoBac G (R), a very strong reduction of larval abundance is achieved, resulting in a massive decrease of blood-seeking females that could otherwise spread from the wetlands to feast on blood from humans and animals within 5 km or more from the larval biotopes. However, there is also a political demand to reduce the usage of the control agent through hypothetical alternatives, such as cattle grazing and mowing of the meadows, as well as hydrological changes of the River Dalalven. An evaluation of these measures showed that they are either insufficient or unrealistic in reducing floodwater mosquito abundance. Thus, we searched for other potential population suppression methods. Using the criteria of efficacy, environmental neutrality and compatibility within an integrated suppression approach, we conclude that Sterile Insect Technique (SIT) and the Incompatibility Insect Technique (IIT) would qualify for a pilot-scale test of their feasibility for the integrated control of the floodwater mosquito Ae. sticticus. The SIT and the IIT are similar strategies involving the release of sterile males which mate with local fertile females and result in infertile eggs. Prerequisites for a sterile male strategy to control Ae. sticticus include: a laboratory colony of the species, a facility for mass-rearing of mosquitoes, the sterilisation of males, a transport strategy, a dispersal system, assay systems for several life stages, and a method capable of reducing the population of this superabundant species before commencing the sterile male release. One factor in favour of implementing the SIT or IIT against Ae. sticticus is that mating occurs in or near well-defined larval breeding areas with specific relation to flood events. Another factor in favour of the SIT or the IIT is the availability of existing methods to measure gender, larvae and egg abundance. Also, existing Bti-treatments can substantially lower the population size before sterile male release. Other prerequisites, like the successful colonization of Ae. sticticus will require more tests and adaptations of existing mosquito rearing protocols. A pilot study is suggested for an isolated study area, protected from reinvasion by Ae. sticticus-females and included in routine Bti-treatments.
Area-wide management of mediterranean fruit fly with the sterile insect technique in South Africa: New production and management techniques pay dividends
19358Venter, J. H., Baard, C. W. L., and Barnes, B. N., AREA-WIDE INTEGRATED PEST MANAGEMENT: Development and Field Application, 2021-11-29 16:27:01.
A mass-rearing facility to produce sterile male Mediterranean fruit flies, Ceratitis capitata (Wiedemann), for a Sterile Insect Technique (SIT) programme in the Hex River Valley in the Western Cape Province started in the late 1990s. The programme was initially underfunded and could only produce about 5 million sterile male flies per week. The resultant aerial release rate of 500 sterile males/ha/week reduced wild Mediterranean fruit fly populations substantially, but not to sufficiently low levels. Due to financial considerations, in 2003 aerial releases were replaced with ground releases targeting all gardens, other hotspots and neglected host plants. It was clear that with more funding, fruit fly mass-rearing facility and field operations could be improved, better quality control could be implemented, and more and better quality male sterile flies could be produced and released. Increased government support in 2001 resulted in a larger mass-rearing facility, and further improvements included the implementation of a quality control management system and the introduction of a new genetic sexing strain (VIENNA 8). The resultant increase in the production of sterile Mediterranean fruit flies of better quality enabled the SIT programme to be systematically introduced to additional fruit production areas. The Mediterranean fruit fly SIT programme was privatised in 2003 and is now operated by FruitFly Africa (Pty) Ltd. In 2009 a new approach to funding was adopted with a renewable Memorandum of Understanding (MoU) between the Department of Agriculture, Forestry and Fisheries (DAFF) and the deciduous fruit and table grape industry. Under the MoU, the DAFF provides 50% of the necessary funding, while 50% is collected from growers through statutory levies. In 2010 a new state of the art mass-rearing facility became operational and subsequent improvements in production processes and facility maintenance resulted in improved fruit fly production and quality. By 2016 sterile male production had increased to 56 million flies per week. After 12 years of ground releases of sterile Mediterranean fruit flies, aerial releases were resumed in three main production areas, and, at the time of writing, include approximately 15 000 ha of commercial deciduous fruit and table grapes. As a result of this well-funded area-wide integrated pest management (AW-IPM) programme, average wild Mediterranean fruit fly populations in the SIT areas have decreased by as much as 73%. The South African Mediterranean fruit fly SIT programme now aims to manage some of the fruit production areas as areas of low pest prevalence. Increased funding and a stable income stream also enabled FruitFly Africa to apply early detection and rapid response programmes for invasive pests such as Bactrocera dorsalis in relevant areas.
The suppression of the False Codling Moth in South Africa using an AW-IPM approach with a SIT component
25890N. Boersma, AREA-WIDE INTEGRATED PEST MANAGEMENT: Development and Field Application, 2021-11-29 10:26:27.
The false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), is native to subSaharan Africa, where it infests various commercial, and wild, fruit-bearing plants. This major pest is not present in the Americas, Europe, and Asia, and therefore has phytosanitary implications, which impose severe limitations on potential South African exports. Consequently, this pest represents a severe threat to the fruit industry of South Africa, in terms of socio-economic impacts on both fruit production and job security. Although the pest can be managed to some extent with insecticides, mating disruption, and orchard sanitation, a long-term environment-friendly solution was needed. This became more evident as T. leucotreta developed resistance to available insecticides, while stricter quarantine measures were enforced by importers of African citrus. In 2002, research commenced on an area-wide integrated pest management (AW-IPM) programme in conjunction with the development of the Sterile Insect Technique (SIT) for the false codling moth. Commercial sterile insect releases started in the 2007-2008 season over 1500 ha of citrus orchards in Citrusdal, Western Cape Province, but by 2017-2018 had gradually expanded to almost 19 000 ha in three different citrus producing regions of South Africa. The programme is currently owned by the Citrus Growers Association (CGA) that have contributed to the steady growth of the SIT programme in the citrus industry. Over the past ten years the status of T. leucotreta as a pest threat was systematically reduced in areas where the SIT was practiced on an area-wide basis, compared to non-release areas.
Major phase of Florida Keys GMO mosquito release complete, company says
19393D. Goodhue, Miami Herald, 2021-11-23 17:29:49.
A British biotechnology company and the Florida Keys Mosquito Control District on Tuesday announced they have “successfully concluded” a major phase in a controversial trial project aimed at wiping out an invasive species of mosquito known to spread dangerous diseases like dengue fever, Zika and chikungunya. In April, the company, Oxitec, placed up to 130 boxes, each filled with millions of genetically altered male Aedes aegypti mosquito larvae, in several locations in the Middle and Lower Keys — hoping they would fly away after hatching and breeding with the naturally occurring local females in the area. Scientists designed a “death mechanism” in the males meant to ensure no viable female offspring would result from the mating. The male offspring, according to Oxitec, will pass on a “self-limiting gene” to half of their young, with the goal of Aedes aegypti breeding themselves out of existence in the Keys, according to the company.
Evaluation of Transgenic Aedes aegypti L. Strain in India: A Friendly Mosquito
19979P. B. Patil, K. K. Yadav, S. K. Dasgupta, U. B. Zehr, S. R. Barwale and B. Char, Genetically Modified and other Innovative Vector Control Technologies, 2021-11-21 11:56:31.
Aedes aegypti L. is a primary vector of dengue and is also responsible for transmission of other arboviral diseases including chikungunya, yellow fever, and Zika virus worldwide. India is attributed with as much as 34% of the global burden of dengue infection as per the recent reports. It is generally acknowledged controlling the vector population in the environment is the key to effectively curb the transmission of vector-borne diseases. Existing conventional methods for controlling the vector populations are not alone sufficient for reducing populations below disease transmission thresholds and would need integration of innovative strategies. With the advancement in modern biotechnology, scientists have been trying to explore the use of genetically engineered insects for their potential use in area-wide method for vector control. One among such strains being widely tested is OX513A Ae. aegypti strain termed as Friendly™ mosquitoes, a genetically engineered strain with a repressible dominant homozygous lethal gene construct and DsRed2 fluorescent marker gene. Male adults of OX513A strain are intended to suppress the wild population of Ae. aegypti in the released environment by population suppression strategy. The lethal gene renders mating events between OX513A males and wild-type females unsuccessful by passing a copy of gene to all the progeny of mated female adults leading to the death of the progeny during development stages in the absence of repressor antidote tetracycline. This OX513A strain was reviewed and recommended for carefully planned pilot deployment and randomized control trials with epidemiological outcomes to build evidence for routine programmatic use against Ae. aegypti-borne diseases by World Health Organization’s Vector Control Advisory Group in the year 2016. The strain is being tested globally in different countries including India for its efficacy and has been deregulated in Brazil for its use in vector control program. This chapter reviews our research investigations conducted on transgenic OX513A Ae. aegypti strain and its potential for use in dengue vector control in India.
Historical perspective and new avenues to control the myiasis-causing fly Cochliomyia hominivorax in Uruguay.
23386Fresia P, Pimentel S, Iriarte V, Marques L, Durán V, Saravia A, Novas R, Basika T, Ferenczi A, Castells D, Saporiti T, Cuore U, Losiewicz S, Fernández F, Ciappesoni G, Dalla-Rizza M and M. A., Agrociencia Uruguay, 25:e974. 2021-11-18 07:43:36.
Mosca de la bichera’ or simply ‘bichera’ are common names given in Uruguay and the region to the primary myiasis-causing species Cochliomyia hominivorax, the New World Screwworm (NWS) fly (Diptera: Calliphoridae). Myiasis happens when dipteran larvae infest live animals at least during some developmental phase to feed on host’s flesh and fluids. For the NWS fly it is mandatory that all three larvae phases develop on living tissues of warm-blooded vertebrates, including humans. Unsurprisingly, this parasitic behavior causes great profit losses to the livestock industry and is also considered a neglected public health issue. NWS is endemic from the tropics and subtropics of the Americas, but has been eradicated from North and Central America through a Sterile Insect Technique (SIT) based Area Wide – Integrated Pest Management (AW-IPM) program that lasted more than 50 years
The drone, the tool of the future to combat its spread
19234T. Thompson, Your Decommissioning News, 2021-11-09 22:01:19.
Drones could become a promising tool in the fight against the tiger mosquito, according to a study published Tuesday by French researchers. French researchers said on Tuesday that drones could, within a few years, integrate into the arsenal of the fight against the tiger mosquito, an invasive species that appeared on mainland France about fifteen years ago, revealing the results of an experiment conducted in Montpellier. The tiger mosquito, Aedes albopictus, now detected in 65 French departments, grows at 80% in individuals, mainly in standing water in gardens. It is more harmful because it stings constantly during the day and can transmit viral diseases such as dengue, chikungunya or Zika if it has been stung by a previous patient. Therefore the first preventive measure against this insect, whose reproduction is preferred by high temperatures, is to systematically empty and overturn containers that may contain water, such as a simple ashtray. But additional methods have emerged in recent years, including the so-called “sterile insect technique” (TIS), which consists of raising male mosquitoes in laboratories, sterilizing them, and then releasing them into the field, where wild females are sterilized. which will not have offspring.
Malaria modeling and optimal control using sterile insect technique and insecticide-treated net
19230L. Cai, L. Bao, L. Rose, J. Summers and W. Ding, Applicable Analysis, 2021-11-05 21:55:36.
We investigate a malaria transmission model with SEIR (susceptible-exposed-infected-recovered) classes for the human population, SEI (susceptible-exposed-infected) classes for the wild mosquitoes and an additional class for the sterile mosquitoes. The basic reproduction number of the disease transmission is obtained, and a release threshold of the sterile mosquitoes is provided. We formulate an optimal control problem in which the goal is to minimize both the infected human populations and the cost to implement two control strategies: the release of sterile mosquitoes and the usage of insecticide-treated nets to reduce the malaria transmission. Adjoint equations are derived, and the characterization of the optimal controls is established. Finally, we quantify the effectiveness of the two interventions aimed at limiting the spread of malaria transmission. A combination of both strategies leads to more rapid elimination of the wild mosquito population that can suppress malaria transmission. Numerical simulations are provided to illustrate the results.
Oxitec Announces Ground-breaking Commercial Launch of Its Friendly™ Aedes aegypti Solution in Brazil
19395Oxitec, COSION, 2021-11-03 17:40:43.
Oxitec, the leading developer of biological solutions to control pests, announced today the landmark commercial launch of its Friendly™ Aedes aegypti solution designed specifically for use by homeowners, businesses, and communities to control the dengue-spreading Aedes aegypti mosquito. This launch represents the first time globally that the benefits of using biologically engineered mosquito control technology that can be purchased directly by consumers. Having received full biosafety commercial approval in 2020 from the Brazilian government's biosafety authority, CTNBio, the company is making its just-add-water solution available for delivery directly to customers' doorsteps starting in the State of São Paulo. Available for purchase online, the product comprises durable outer boxes and Friendly™ male mosquito egg refill packs. Once delivered, customers need only to add water to the Friendly™ box, place it in a garden, patio, or around a home or business, and the boxes will produce Oxitec's non-biting male mosquitoes over time, which disperse to find and mate with invasive, biting Aedes aegypti females. Their female offspring cannot survive, which means fewer biting female mosquitoes in the following generations. While the Friendly™ Aedes aegypti males pursue and mate with female Aedes aegypti, customers need only reactivate the easy-to-use box once per month. This technology controls the pest without harming beneficial species like bees and butterflies and does not persist in the environment.
Temperature-Inducible Precision-Guided Sterile Insect Technique
19268N. P. Kandul, J. R. Liu and O. S. Akbari, CRISPR Journal, 14. 2021-11-03 16:11:04.
Releases of sterile males are the gold standard for many insect population control programs, and precise sex sorting to remove females prior to male releases is essential to the success of these operations. To advance traditional methods for scaling the generation of sterile males, we previously described a CRISPR-mediated precision-guided sterile insect technique (pgSIT), in which Cas9 and gRNA strains are genetically crossed to generate sterile males for mass release. While effective at generating F-1 sterile males, pgSIT requires a genetic cross between the two parental strains, which requires maintenance and sexing of two strains in a factory. Therefore, to advance pgSIT further by removing this crossing step, here we describe a next-generation temperature-inducible pgSIT (TI-pgSIT) technology and demonstrate its proof-of-concept in Drosophila melanogaster. Importantly, we were able to develop a true breeding strain for TI-pgSIT that eliminates the requirement for sex sorting-a feature that may help further automate production at scale.
Investigation of Developmental Stage/Age, Gamma Irradiation Dose, and Temperature in Sterilization of Male Aedes aegypti (Diptera: Culicidae) in a Sterile Insect Technique Program
20236B. Ernawan, T. Anggraeni, S. Yusmalinar and I. Ahmad, Journal of Medical Entomology, 59:320-327. 2021-10-01 09:18:43.
The sterilization process using gamma irradiation is a crucial component in a program using sterile insect technique (SIT) to control Aedes aegypti. Unfortunately, there is no efficient standard protocol for sterilizing mosquitoes that can produce a high level of sterility while maintaining mating ability and longevity. Therefore, we conducted a study of the critical factors necessary to develop such a standard protocol. In this study, male Ae. aegypti pupae, as well as adults aged 1 d and 3 d, were irradiated using a Gamma-cell 220 irradiator doses of 0, 20, 40, 60, 70, 80, and 100 Gray (Gy). In addition, male Ae. aegypti in the pupal and adult stage aged 1 d were irradiated at a dose of 70 Gy at various temperatures. Changes in emergence rates, longevity, sterility, and mating competitiveness were recorded for each combination of parameters. Results showed that an in-crease of irradiation dose leads to a rise of induced sterility at all developmental stages, while simultaneously reducing emergence rate, survival, and mating competitiveness. Higher temperatures resulted in increased levels of sterility, reduced longevity, and did not affect the ability to mate. This study found that an irradiation dose of 70 Gy at a temperature between 20.00 and 22.30°C administered in the pupal stage induced a high level of sterility (around 98%), while maintaining mating competitiveness and longevity
Plan for California’s Genetically Modified Mosquitoes Draws Fire
18813T. Baltz, Bloomberg Law, 2021-09-29 15:13:31.
A U.K.-based biotech company’s proposal to release genetically engineered mosquitoes in California as a disease-control measure is prompting criticism that the program could create unnatural consequences. Oxitec says it would unleash safe, non-biting male mosquitoes to reduce the population of mosquitoes that spread dengue, Zika, yellow fever, and other diseases. It applied in August for an Environmental Protection Agency permit to release the genetically modified organisms, or GMOs, for pilot projects in the state. Opponents say the company’s plan lacks rigorous assessments of potentially serious health and environmental impacts, and could have “disastrous consequences” in the U.S. and other countries. ...
Life Table of Bactrocera zonata (Saunders) (Diptera: Tephritidae) for Sterile Insect Technique (SIT) in Mauritius
19008R. D. Bhoyroo, S. Facknath and P. Sookar, African Entomology, 29:361-369. 2021-09-28 15:26:50.
Fruit flies (Tephritidae) have been reported to be a serious pest worldwide. In Mauritius, the major fruit fly species of economic and quarantine importance in agricultural production are Bactrocera zonata (Saunders), Zeugodacus cucurbitae (Coquillett) and Bactrocera dorsalis (Hendel). In line with the government's policy for sustainable and organic agriculture under the challenge of climate change, the Sterile Insect Technique (SIT) is being investigated as an alternative to chemical control. For successful cost-effective SIT programme island-wide, the production of competitive and sterile individuals for release is a key requirement. The aim of this study was to investigate the life cycle parameters of B. zonata to evaluate the feasibility of optimum mass rearing of this species. It was observed that B. zonata has a pre-oviposition period of 8 days, an oviposition duration of 51 days, the number of eggs per female along the complete oviposition period was 705 eggs and the peak egg hatchability varied from 88.5 to 91.5 %. The study showed that egg collection could be started as from day 13. The findings demonstrated that 5 weeks of egg collection is optimal for a rearing facility of B. zonata and production cages should be discarded on day 41. It was found that B. zonata has a net reproductive rate of 300.04 females and a mean generation time of 28.73 days. Given a positive Ro and a short T, it can be concluded that mass rearing of B. zonata is economically viable. Within a short period a laboratory population of this species for mass rearing can be established.
Predicting the spread and persistence of genetically modified dominant sterile male mosquitoes
18680A. Ickowicz, S. D. Foster, G. R. Hosack and K. R. Hayes, Parasites and Vectors, 14:480. 2021-09-16 13:03:47.
Reproductive containment provides an opportunity to implement a staged-release strategy for genetic control of malaria vectors, in particular allowing predictions about the spread and persistence of (self-limiting) sterile and male-biased strains to be compared to outcomes before moving to (self-sustaining) gene-drive strains. In this study, we: (i) describe a diffusion–advection–reaction model of the spread and persistence of a single cohort of male mosquitoes; (ii) elicit informative prior distributions for model parameters, for wild-type (WT) and genetically modified dominant sterile strains (DSM); (iii) estimate posterior distributions for WT strains using data from published mark-recapture-release (MRR) experiments, with inference performed through the Delayed-Rejection Adaptive Metropolis algorithm; and (iv) weight prior distributions, in order to make predictions about genetically modified strains using Bayes factors calculated for the WT strains. If a single cohort of 5000 genetically modified dominant sterile male mosquitoes are released at the same location as previous MRR experiments with their WT counterparts, there is a 90% probability that the expected number of released mosquitoes will fall to < 1 in 10 days, and that by 12 days there will be a 99% probability that no mosquitoes will be found more than 150 m from the release location. Spread and persistence models should form a key component of risk assessments of novel genetic control strategies for malaria vectors. Our predictions, used in an independent risk assessment, suggest that genetically modified sterile male mosquitoes will remain within the locality of the release site, and that they will persist for a very limited amount of time. Data gathered following the release of these mosquitoes will enable us to test the accuracy of these predictions and also provide a means to update parameter distributions for genetic strains in a coherent (Bayesian) framework. We anticipate this will provide additional insights about how to conduct probabilistic risk assessments of stage-released genetically modified mosquitoes.
Novel Sterile Insect Technology Program Results in Suppression of a Field Mosquito Population and Subsequently to Reduced Incidence of Dengue
30892Lisiane de Castro Poncio, Filipe Apolinário dos Anjos, Deborah A de Oliveira, Débora Rebechi, et al., The Journal of Infectious Diseases, 224:1005-1014. 2021-09-15 08:29:17.
There is a steady rise in the global incidence of Aedes-borne arbovirus disease. It has become urgent to develop alternative solutions for mosquito vector control. We developed a new method of sterilization of male mosquitoes with the goal to suppress a local Aedes aegypti population and to prevent the spread of dengue. Sterile male mosquitoes were produced from a locally acquired Ae. aegypti colony by using a treatment that includes double-stranded RNA and thiotepa. A field study was conducted with sterile mosquito releases being performed on a weekly basis in predefined areas. There were 2 intervention periods (INT1 and INT2), with treatment and control areas reversed between INT1 and INT2. During INT1, releases in the treated area resulted in up to 91.4% reduction of live progeny of field Ae. aegypti mosquitoes recorded over time, while the control neighborhoods (no releases of sterile male mosquitoes) remained highly infested. The successful implementations of the program during INT1 and INT2 were associated with 15.9-fold and 13.7-fold lower incidences of dengue in the treated area compared to the control areas, respectively. Our data show the success of this new sterile insect technology-based program in preventing the spread of dengue.
Mosquitoes Sterilized by CRISPR Powered Precision System
18648A. A. Sarkar, Genetic Engineering & Biotechnology News, 2021-09-13 20:06:53.
Each year millions around the world are infected by dengue, chikungunya, and Zika viruses. The principal culprit behind the transmission of these deadly diseases is the mosquito vector, Aedes aegypti. Conventional methods of pest control have so far fallen short. To curb the spread of A. aegypti, researchers at the University of California, San Diego (UCSD), have now developed a CRISPR-based molecular genetic control system called precision-guided sterile insect technique (pgSIT) that alters insect genes to generate flightless female and sterile male mosquitoes. The pgSIT system can be deployed effectively at any stage in the life cycle of the mosquito. The authors used mathematical models to empirically demonstrate that once released, male A. aegypti mosquitoes sterilized using the pgSIT system can compete, suppress, and eliminate fertile mosquito populations in the wild. The pgSIT system is not limited to restricting mosquito populations, it can be adapted to different vectors to curb transmissible diseases in a safe, confinable, and reversible manner, the authors claim. These findings are reported in the Nature Communications article, “Suppressing mosquito populations with precision guided sterile males.”
New precision-guided sterile insect technique designed to control disease-spreading mosquitoes
18674E. Henderson, News Medical Life Sciences, 2021-09-11 19:59:16.
Leveraging advancements in CRISPR-based genetic engineering, researchers at the University of California San Diego have created a new system that restrains populations of mosquitoes that infect millions each year with debilitating diseases. The new precision-guided sterile insect technique, or pgSIT, alters genes linked to male fertility--creating sterile offspring--and female flight in Aedes aegypti, the mosquito species responsible for spreading wide-ranging diseases including dengue fever, chikungunya and Zika.Details of the new pgSIT are described September 10, 2021, in the journal Nature Communications. pgSIT differs from "gene drive" systems that could suppress disease vectors by passing desired genetic alterations indefinitely from one generation to the next. Instead, pgSIT uses CRISPR to sterilize male mosquitoes and render female mosquitoes, which spread disease, as flightless. The system is self-limiting and is not predicted to persist or spread in the environment, two important safety features that should enable acceptance for this technology. Akbari says the envisioned pgSIT system could be implemented by deploying eggs of sterile males and flightless females at target locations where mosquito-borne disease spread is occurring.
Genetic engineering tech promises to sterilize disease-spreading mosquitoes
18525B. Hays, UPI, 2021-09-10 16:01:17.
Inspired by improvements in CRISPR-based genetic engineering, scientists have developed a more precise insect sterilization system to curtail, or even eliminate, disease-spreading Aedes aegypti mosquito populations. The so-called "precision-guided sterile insect technique," or pgSIT, relies on gene alterations that disrupt fertility in males and flight in females. Gene-altered males are released into a problematic population to compete with healthy males. "pgSIT is a new scalable genetic control system that uses a CRISPR-based approach to engineer deployable mosquitoes that can suppress populations," corresponding author Omar Akbari said in a press release. Map of malaria parasite's gene activity reveals new targets for drugs, vaccines "Males don't transmit diseases so the idea is that as you release more and more sterile males, you can suppress the population without relying on harmful chemicals and insecticides," said Akbari, a professor of biological sciences at the University of California, San Diego.
Genetic Engineering Technology Promises To Sterilize Disease-Spreading Mosquito Populations
18519D. Gyllhem, VIGOURTIMES, 2021-09-10 15:00:02.
Inspired by improvements in CRISPR-based genetic engineering, scientists have developed a more precise insect sterilization system to curtail, or even eliminate, disease-spreading Aedes aegypti mosquito populations. The so-called “precision-guided sterile insect technique,” or pgSIT, relies on gene alterations that disrupt fertility in males and flight in females. Gene-altered males are released into a problematic population to compete with healthy males. Scientists described the novel method in a new paper, published Friday in the journal Nature Communications. “pgSIT is a new scalable genetic control system that uses a CRISPR-based approach to engineer deployable mosquitoes that can suppress populations,” corresponding author Omar Akbari said in a press release. “Males don’t transmit diseases so the idea is that as you release more and more sterile males, you can suppress the population without relying on harmful chemicals and insecticides,” said Akbari, a professor of biological sciences at the University of California, San Diego.
New Technology Designed to Genetically Control Disease-spreading Mosquitoes
18515M. Aguilera, UC San Diego News Center, 2021-09-10 14:49:00.
Leveraging advancements in CRISPR-based genetic engineering, researchers at the University of California San Diego have created a new system that restrains populations of mosquitoes that infect millions each year with debilitating diseases. An illustration by study coauthor Stephanie Gamez depicts flightless females and sterile male mosquitoes, features of the new precision-guided sterile insect technique, or pgSIT, which is designed to control disease-spreading Aedes aegypti mosquitoes. The new precision-guided sterile insect technique, or pgSIT, alters genes linked to male fertility—creating sterile offspring—and female flight in Aedes aegypti, the mosquito species responsible for spreading wide-ranging diseases including dengue fever, chikungunya and Zika. “pgSIT is a new scalable genetic control system that uses a CRISPR-based approach to engineer deployable mosquitoes that can suppress populations,” said UC San Diego Biological Sciences Professor Omar Akbari. “Males don’t transmit diseases so the idea is that as you release more and more sterile males, you can suppress the population without relying on harmful chemicals and insecticides.”
Suppressing mosquito populations with precision guided sterile males
18513M. Li, T. Yang, M. Bui, S. Gamez, T. Wise, N. P. Kandul, J. Liu, L. Alcantara, H. Lee, J. R. Edula, R. Raban, Y. Zhan, Y. Wang, N. DeBeaubien, J. Chen, H. M. Sánchez C, J. B. Bennett, I. Antoshechkin, C. Montell, J. M. Marshall and O. S. Akbari, Nature Communications, 12:5374. 2021-09-10 14:42:45.
The mosquito Aedes aegypti is the principal vector for arboviruses including dengue/yellow fever, chikungunya, and Zika virus, infecting hundreds of millions of people annually. Unfortunately, traditional control methodologies are insufficient, so innovative control methods are needed. To complement existing measures, here we develop a molecular genetic control system termed precision-guided sterile insect technique (pgSIT) in Aedes aegypti. PgSIT uses a simple CRISPR-based approach to generate flightless females and sterile males that are deployable at any life stage. Supported by mathematical models, we empirically demonstrate that released pgSIT males can compete, suppress, and even eliminate mosquito populations. This platform technology could be used in the field, and adapted to many vectors, for controlling wild populations to curtail disease in a safe, confinable, and reversible manner.
Genetically Modified Mosquitoes — What’s The Real Story?
18289SPW Staff, Southeast Product Weekly, 2021-09-02 14:58:32.
You’ve heard about the genetically modified mutant mosquitoes being released in the Florida Keys — but what exactly is going on, and how, and why? Basically, researchers in parts of the Florida Keys are releasing male mosquitoes that have been genetically modified to produce only male offspring. In a generation or two, there are no more girl mosquitoes to have baby mosquitoes. That’s the simple explanation. t might help to know this experiment was tried once before — successfully — in Brazil.There’s now a new, science-based online information resource about genetically modified mosquitoes from University of Florida scientists at the UF/IFAS Florida Medical Entomology Laboratory. “Genetically Modified Mosquitoes” is the latest publication on Ask IFAS, UF/IFAS’ Electronic Data Information Source (EDIS) peer-reviewed site, that provides relevant information regarding the pilot projects in select areas of the Florida Keys. The experiments, which are a collaboration between the Florida Keys Mosquito Control District and the biotechnology company Oxitec founded in the United Kingdom out of Oxford University, are permitted by the U.S. Environmental Protection Agency (EPA).
UF/IFAS Researchers Explain Science Behind Genetically Modified Mosquitoes
18276PCT Staff, Pest Control Technology, 2021-09-01 14:14:47.
South Florida residents seeking science-based information about genetically modified mosquitoes can access a new, online resource from University of Florida scientists at the UF/IFAS Florida Medical Entomology Laboratory.“ Genetically Modified Mosquitoes” is the latest publication on Ask IFAS, UF/IFAS’ Electronic Data Information Source (EDIS) peer-reviewed site, that provides relevant information regarding the pilot projects in select areas of the Florida Keys. The experiments, which are a collaboration between the Florida Keys Mosquito Control District and the biotechnology company Oxitec founded in the United Kingdom out of Oxford University, are permitted by the U.S. Environmental Protection Agency (EPA). The UF/IFAS publication describes the mosquito species being targeted, what to expect from the pilot projects, why this approach is being used as well as answers to other frequently asked questions about genetically modified mosquitoes. The publication also lists additional linked resources for readers interested in more detailed information on the topic and science. “The rationale for producing this document is to help inform the public and those who are interested or impacted by the current trials run by Oxitec,” said Eric Caragata, an assistant professor at UF/IFAS FMEL. “As scientists who are not directly involved in the project, we wanted to clearly address some of the important questions and concerns.”
New Way to Reduce Diseases Spreading Through Mosquitos
18207Dr Jayashree, Medindia, 2021-08-25 15:01:01.
Using a gene editing tool known as CRISPR-Cas9 that targets specific genes tied to fertility in male mosquitoes, we can slow the spread of potentially deadly diseases such as Zika, dengue fever and yellow fever. This genome editing tool is creating a buzz in the science world, as it is faster, cheaper and more accurate than previous techniques of editing DNA and has a wide range of potential applications.. Researchers at the Army's Institute for Collaborative Biotechnologies and the University of California Santa Barbara experimented with the Aedes aegypti mosquitoes, found in tropical, subtropical and temperate regions throughout the world
Gene Editing Could Render Mosquitos Infertile
18168U.S. Army DEVCOM Army Research Laboratory Public Affairs, U.S. Army, 2021-08-23 14:51:29.
Sterile males and females can synergistically suppress wild pests targeted by sterile insect technique
18837Y. Ikegawa, K. Ito, C. Himuro and A. Honma, Journal of Theoretical Biology, 530. 2021-08-23 11:21:38.
We constructed a mathematical model to examine the contribution of sterile males and females to the pest-control effect and the synergy between them. We consider that males seek out and court females in accord with their own female searching ability and preference, and that females subsequently choose one male from among males courting them in accordance with their own preference. Using this model, we compared the pest-control effect of bisexual and unisexual release, focusing on the difference in mating systems of the targeted insects. We showed that for swarm-type mating systems (with few courtship chances with higher encounter rates), bisexual release was the most effective, irrespective of the relative female searching ability between wild and sterile males. In this case, sterile females indirectly reduce wild females mating with either male by absorbing courtship from both wild and sterile males. By contrast, bisexual release is the most effective for scramble-type mating systems (more courtship chances with lower encounter rates) only when the female searching ability of sterile males is lower than that of wild males. In this case, sterile females absorb courtship from males with higher searching abilities. Therefore, the net impact of sterile females depends on the difference in sexual performance between wild and sterile males. Because the sexual performance of sterile insects is often degraded during the process of sterilization, we suggest that bisexual release can be a compatible measure to efficiently suppress wild pest populations.
Genetically Modified Mosquitoes
18286E. P. Caragata, Y. Lee and E. A. Buckner, UF IFAS Extension Service, 2021-08-17 14:49:18.
Genetically modified (GM) mosquitoes are controversial, partly because of misinformation. This publication provides science-based information about GM mosquitoes to the public and anyone involved in mosquito control. It explains what GM mosquitoes are and why they are being investigated as a tool for mosquito control. Describes a GM mosquito pilot project in Florida, and includes FAQs and answers explaining how GM mosquitoes are created and their potential impacts on people and the environment.
A Monte Carlo study to investigate the feasibility to use the Moroccan panoramic irradiator in sterile insect technique programs
18159A. Aknouch, Y. El-ouardi, L. Hamroud, R. Sebihi, M. Mouhib, M. Yjjou, A. Didi and A. Choukri, Radiation and Environmental Biophysics, 2021-08-14 18:10:19.
Mediterranean fly pest (Ceratitis) is one of the most destructive pests of fruit species in Morocco. The sterile insect technique (SIT) is an environmentally friendly strategy that uses ionizing radiation to sterilize adult insects. Morocco has a panoramic gamma irradiator used to irradiate agri-food products. This irradiator is not dedicated to SIT programs due to its geometry that does not allow to obtain a dose uniformity ratio (DUR) recommended for such applications. This article presents a Monte Carlo study to investigate the feasibility of using the panoramic gamma irradiator at the National Institute for Agronomic Research (NIAR) of Tangier, Morocco, to setting up SIT methods and contributing to Ceratitis control programs. The Monte Carlo method was used to simulate the concrete bunker in which the panoramic gamma irradiator is installed. To obtain a recommended DUR required for SIT programs, two cells similar of the Gammacell-220 irradiator, which is mainly used in the SIT programs around the world, were simulated inside the concrete bunker. The simulation and calculations were performed using the MCNPX-2.7e Monte Carlo simulation code. It is demonstrated that at both investigated positions, the spatial distribution of dose rates in the two modeled irradiation cells, which were similar to a gammacell-220 irradiator cell, are uniform enough that the cells can be used for SIT programs. It is concluded that the panoramic irradiator at NIAR can be used to contribute to the control of Mediterranean fly pest and other insect pests in Morocco.
Oxitec eyes California for its next GM mosquito pilot projec
18075J. Conrow, 2021-08-11 17:09:34.
Buoyed by its success in the Florida Keys, Oxitec Ltd. is now looking to California to test its program for controlling mosquito pests through genetic engineering, rather than insecticides. The field research is intended to show that genetically modified (GM) mosquitoes are a viable alternative to spraying insecticides in a bid to control a disease-carrying species of mosquito. Due to climate change, the invasive Aedes aegypti mosquitoes are spreading into new regions throughout the Western United States, including more than 300 cities and towns across California. Aedes aegypti transmit dengue, Zika, heartworm and other diseases, many of which have no treatments or vaccines.
Oxitec Advances Process to Bring Friendly™ Mosquito Technology to California to Help Government Agencies Protect Public Health
18046Oxitec, Oxitec, 2021-08-09 15:11:08.
Following successful launch of its Friendly™ Aedes aegypti pilot program in the Florida Keys, Oxitec, the leading developer of biological solutions to control pests that transmit disease, destroy crops and harm livestock, has requested approval from the U.S. Environmental Protection Agency (EPA) to pilot its technology in California in partnership with local government agencies that have demonstrated interest in evaluating the technology.
Transgenic expression of Nix converts genetic females into males and allows automated sex sorting in Aedes albopictus
17888C. Lutrat, R. P. Olmo, T. Baldet, J. Bouyer and E. Marois, bioRxiv, 2021.07.28.454191. 2021-07-29 12:43:42.
Aedes albopictus is a major vector of arboviruses. Better understanding of its sex determination is crucial for developing mosquito control tools, especially genetic sexing strains. In Aedes aegypti, Nix is the primary gene responsible for masculinization and Nix-expressing genetic females develop into fertile, albeit flightless, males. In Ae. albopictus, Nix has also been implicated in masculinization but its role remains to be further characterized. In this work, we established Ae. albopictus transgenic lines ectopically expressing Nix. Several were composed exclusively of genetic females, with transgenic individuals being phenotypic and functional males due to the expression of the Nix transgene. Their reproductive fitness was marginally impaired, while their flight performance was similar to controls. Overall, our results show that Nix is sufficient for full masculinization in Ae. albopictus. Moreover, the transgene construct contains a fluorescence marker allowing efficient automated sex sorting. Consequently, such strains constitute valuable sexing strains for genetic control.Competing Interest StatementThe authors have declared no competing interest.
Sex separation of Aedes spp. mosquitoes for sterile insect technique application: a review
17905B. M. Moran-Aceves, C. F. Marina, A. Dor, P. Liedo and J. Toledo, Entomologia Experimentalis Et Applicata, 10. 2021-07-24 15:04:30.
Separation of the sexes is necessary for the application of the sterile insect technique (SIT) in mosquitoes due to the hematophagous habits and disease vector activity of the females. In this review we analyze the history, current status, and future perspectives for the development of genetic sexing strains (GSS) of Aedes mosquitoes (Diptera: Culicidae). Various genetic control methods for mosquitoes are reviewed, as are their need for sex-separation methods. We focus on areas of opportunity where GSS developed with classical genetic methods can be used. Regulatory restrictions and social acceptance of various control methods are analyzed. We conclude that the development of GSS by classical methods represents the most viable option for separation of the sexes and the application of large-scale SIT programs within an area-wide integrated vector management (AW-IVM) approach.
Using Moderate Transgene Expression to Improve the Genetic Sexing System of the Australian Sheep Blow Fly Lucilia cuprina
17753Y. Yan, M. E. Williamson and M. J. Scott, Insects, 11. 2021-07-19 14:36:16.
The sterile insect technique (SIT) is a promising strategy to control the Australian sheep blow fly Lucilia cuprina, a major pest of sheep. We have previously developed a transgenic embryonic sexing system (TESS) for this pest to facilitate the potential SIT application. TESS carry two transgenes, a tetracycline transactivator (tTA) driver and a tTA-activated pro-apoptotic effector. TESS females die at the embryonic stage unless tetracycline is supplied in the diet. However, undesired female sterility was observed in some TESS strains without tetracycline due to expression of tTA in ovaries. Here we investigate if TESS that combine transgenes with relatively low/moderate expression/activity improves the fertility of TESS females. tTA driver lines were evaluated for tTA expression by quantitative real time PCR and/or by crossing with a tTA-activated RFPex effector line. Fertility and lethality tests showed that a TESS strain containing a driver line with moderate tTA expression and an effector line showing moderate pro-apoptotic activity could recover the fertility of parental females and eliminated all female offspring at the embryonic stage. Consequently, such a strain could be further evaluated for an SIT program for L. cuprina, and such a “moderate strategy” could be considered for the TESS development in other pest species.
Yes, genetically modified mosquitoes do exist, but they don’t bite and aren’t harmful to humans
17815E. Jones and M. Chamberlin, WKYC Studios, 2021-07-19 14:35:11.
In 2021, Oxitec, a biotechnology company that develops genetically modified insects that safely and sustainably control pests that spread disease, damage crops and harm livestock across the globe, partnered with the Florida Keys Mosquito Control District (FKMCD) to evaluate the effectiveness of Oxitec mosquitoes to control the invasive, disease-spreading Aedes aegypti mosquito in the Florida Keys. Aedes aegypti mosquitoes typically live in tropical and subtropical climates, according to the CDC. The agency says Aedes aegypti mosquitoes are more likely to spread Zika, dengue, chikungunya and other viruses than other types of mosquitoes because they live near and prefer to feed on people. “One of the things that sort of works against the Aedes aegypti is that they are anthropophilic,” said Dr. Floyd Shockley, the collections manager in the Department of Entomology at the Smithsonian National Museum of Natural History. “Most of the mosquitoes that feed on humans tend to fly at night, but Aedes aegypti flies during the day. It's actually the mosquito that you usually run into when you're out hiking.” Dr. Nathan Rose, the head of Regulatory Affairs at Oxitec, tells VERIFY the company produces genetically modified male mosquitoes to target the wild Aedes aegypti female mosquitoes because they are the main vector for viral diseases.
The Possible Role of Microorganisms in Mosquito Mass Rearing
17741L. Chersoni, A. Checcucci, M. Malfacini, A. Puggioli, F. Balestrino, M. Carrieri, I. Piunti, M. L. Dindo, P. Mattarelli and R. Bellini, Insects, 12. 2021-07-15 13:10:37.
In Europe, one of the most significant mosquitoes of public health importance is Aedes albopictus (Skuse), an allochthonous species of Asian origin. One of the most promising control methods against Aedes albopictus is the sterile insect technique (SIT), which consists of mass rearing the target species, separation of males from females, and male exposure to sterilizing ionizing radiation. Once released in the environment, the sterile males are expected to search for wild females to mate with. If mating occurs, no offspring is produced. The quality of sterile males is a crucial aspect in SIT programs in order to optimize effectiveness and limit production costs. The integration of probiotic microorganisms in larval and adult mosquito diets could enhance the quality parameters of the released sterile males. In this review, we attempt to give the most representative picture of the present knowledge on the relationships between gut microbiota of mosquitoes and the natural or artificial larval diet. Furthermore, the possible use of probiotic microorganisms for mosquito larvae rearing is explored. Based on the limited amount of data found in the literature, we hypothesize that a better understanding of the interaction between mosquitoes and their microbiota may bring significant improvements in mosquito mass rearing for SIT purposes.
Sterile Insect Technique (SIT) and Its Applications
17733K. Bourtzis and M. J. B. Vreysen, Insects, 12. 2021-07-13 15:57:10.
Although most insect species have a beneficial role in the ecosystems, some of them represent major plant pests and disease vectors for livestock and humans. During the last six–seven decades, the sterile insect technique (SIT) has been used as part of area-wide integrated pest management strategies to suppress, contain, locally eradicate or prevent the (re)invasion of insect pest populations and disease vectors worldwide. This Special Issue on “Sterile insect technique (SIT) and its applications”, which consists of 27 manuscripts (7 reviews and 20 original research articles), provides an update on the research and development efforts in this area. The manuscripts report on all the different components of the SIT package including mass-rearing, development of genetic sexing strains, irradiation, quality control as well as field trials.
Unique effort underway to control deadly mosquitos in Florida Keys
17823K. Corso and L. Aguirre, Local10.com, 2021-07-12 14:48:28.
According to the World Health Organization, more than 50% of the world’s population is under the threat of mosquito borne diseases. In South Florida, the Keys are a hot spot for infection and now the first place in the United States for a novel approach to eradicating these deadly insects. A mosquito control effort in the works for over a decade is now off the ground. The Oxitec Project uses genetically modified Aedes Aegypti male mosquitos to mate with females of the Aedes Aegypti species which carry some of the deadliest diseases “Ades Aegypti themselves are responsible for transmitting Yellow Fever, Dengue Fever, Chikungunya, Zika virus, said Andrea Leal, entomologist and executive director of the Florida Keys Mosquito Control District. Only the female mosquitos bite so the Oxitec Project targets the female population of the species. “So with this project, we’re releasing males only and they’ve been modified with a female lethal gene which means as they go out and they mate with our wild females, all those female offspring will die,” Leal said.
Improvement of the Mass-Rearing Protocols for the South American Fruit Fly for Application of the Sterile Insect Technique
17764T. Mastrangelo, A. Kovaleski, B. Maset, M. D. Costa, C. Barros, L. A. Lopes and C. Caceres, Insects, 12. 2021-07-09 14:59:26.
The existing rearing protocols for Anastrepha fraterculus must be reviewed to make economically viable the production of sterile flies for their area-wide application. Additionally, evidence of sexual incompatibility between a long-term mass-reared Brazilian strain and wild populations has been found. To address these issues, this study aimed to refine rearing protocols and to assess the suitability of an A. fraterculus strain for the mass production of sterile flies. A series of bioassays were carried out to evaluate incubation times for eggs in a bubbling bath and to assess the temporal variation of egg production from ovipositing cages at different adult densities. A novel larval diet containing carrageenan was also evaluated. Egg incubation times higher than 48 h in water at 25 °C showed reduced larval and pupal yields. Based on egg production and hatchability, the density of 0.3 flies/cm2 can be recommended for adult cages. The diet with carrageenan was suitable for mass production at egg-seeding densities between 1.0 and 1.5 mL of eggs/kg of diet, providing higher insect yields than a corn-based diet from Embrapa. Even after two years of being reared under the new rearing protocols, no sexual isolation was found between the bisexual strain and wild flies.
Comparative response to post-production process of two Anastrepha ludens strains: Application in the sterile insect technique
17725J. Arredondo, J. F. Aguirre-Medina, J. S. Meza, J. Cancino and F. Diaz-Fleischer, Journal of Applied Entomology, 11. 2021-07-07 14:54:23.
The new desiccation-resistant (DR) strain of Anastrepha ludens Loew differs in its life-history traits from the non-selected strain (NS). Given the innate resistance of DR flies to stressors, it is necessary to determine the packing and shipment conditions for their use in the sterile insect technique (SIT). First, we used pupae to evaluate the interaction of hypoxia period (12, 24 and 36 hr) and temperature (15.3 (+/- 0.9), 19.5 (+/- 1.0), 25.5 (+/- 0.6) and 30.1 (+/- 0.5) C-o). Second, adults were exposed to densities of 1.0, 1.3 and 1.5 flies/cm(2) and chilling periods of 0, 3 and 5 hr. We observed a negative relationship of emergence and flight ability with hypoxia period and temperature in both strains especially when flies were exposed to 36 hr of hypoxia and 30celcius. Interestingly, knock-down time decreased as male density increased, but when chilling time increased, recovery time also increased. Both chilling time and male density had negative effects on male weight. Chilling time reduced male survival when exposed to desiccation, while both chilling time and male density decreased male survival under starvation conditions. Negative effects on number of matings were observed only on the first day after chilling but not on the following days. We found that DR flies survive approximately twice as long as flies from the NS strain when exposed to starvation or desiccation stressors. We discuss our results on the basis of the potential use of DR flies in SIT programmes.
Effect of the timing of pupal irradiation on the quality and sterility of oriental fruit flies (Diptera: Tephritidae) for use in Sterile Insect Technique
17781T. J. Fezza, P. A. Follett and T. E. Shelly, Applied Entomology and Zoology, 8. 2021-07-05 17:37:25.
The Sterile Insect Technique (SIT) is a target-specific, biologically based method used to control pestiferous tephritids entailing the release of mass-reared, sterilized males of the target species to achieve sterile male x wild female matings. As documented for several tephritid species, sterilizing irradiation may have adverse effects on various biological parameters, including life span, flight ability, and mating competitiveness. To minimize these impacts and ensure sterility, released flies must be irradiated at a precise dose at a specific and uniform age. The objective of the present study was to determine the impact of pupal age at the time of irradiation on flight ability, male survival, fertility, and mating competitiveness for the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) irradiated at 100 Gy. We concluded that flies irradiated as pupae 4 days before emergence were significantly compromised with respect to flight ability and male survival when compared to flies irradiated 1 or 2 days before emergence. Additionally, we determined that crosses between males irradiated 1 day before emergence with non-irradiated females yielded significantly more pupae than the same cross with males irradiated at 2, 3, and 4 days before emergence. Although rare, the occurrence of pupae and emerged adults suggested low levels of fertility for flies irradiated as pupae 1 day before emergence, but complete sterility at 2, 3, and 4 days before emergence. These findings suggest that SIT programs can potentially irradiate pupae at 2 or 3 days before emergence without compromising the quality of the released flies, which would permit the distribution of flies over greater distances.
Remating in Ceratitis capitata sterile males: Implications in sterile insect technique programmes
17827M. Catala-Oltra, E. Llacer, O. Dembilio, I. Pla, A. Urbaneja and M. Perez-Hedo, Journal of Applied Entomology, 8. 2021-07-02 14:57:45.
Sterile insect technique (SIT) is used, among other biological control tools, as a sustainable measure for the management of Ceratitis capitata Wiedemann (Diptera: Tephritidae) in many agricultural regions where this pest can trigger severe economic impacts. The tendency of wild females to remate multiple times has been deeply studied; it has been a common point of controversy when evaluating SIT programmes. Nevertheless, the remating potential of the released sterile males remains unknown. Here, under laboratory conditions, the remating capability of mass-reared sterile males was determined. Wild-type virgin females were offered to sterile males (Vienna-8 strain), which had the opportunity to mate up to four consecutive times. The remating assays were carried out at 24 hr, 48 hr, 4 days and 7 days after the first mating. At the end of each tested time period, males were divided according to their mating response, mated or unmated, and subsequently reused for the next round of mating assays. The frequency of successful remating in each tested time period was obtained. Insemination was confirmed by determining the sperm transfer in mated female spermathecae by quantitative real-time PCR. Our results demonstrate that 73% of the mass-reared sterile males were able to remate 24 hr after the first mating, 55% of which remated again the day after. Close to 25% of the V8 sterile males tended to copulate in all of the four mating opportunities. The qPCR analysis of the spermathecae contents verified an effective transfer of V8 sperm to wild females with every mating; 99% of copulations resulted in sperm transfer. These findings shed light on the remating potential of V8 sterile males, an aspect until now underestimated in many SIT programmes.
A transgenic female killing system for the genetic control of Drosophila suzukii
17506M. F. Schetelig, J. Schwirz and Y. Yan, Scientific Reports, 11:12938. 2021-06-24 14:13:24.
The spotted wing Drosophila (Drosophila suzukii) is an invasive pest of soft-skinned fruit crops. It is rapidly transmitted in Europe and North America, causing widespread agricultural losses. Genetic control strategies such as the sterile insect technique (SIT) have been proposed as environment-friendly and species-restricted approaches for this pest. However, females are inefficient agents in SIT programs. Here we report a conditional female-killing (FK) strategy based on the tetracycline-off system. We assembled sixteen genetic constructs for testing in vitro and in vivo. Twenty-four independent transgenic strains of D. suzukii were generated and tested for female-specific lethality. The strongest FK effect in the absence of tetracycline was achieved by the construct containing D. suzukii nullo promoter for early gene expression, D. suzukii pro-apoptotic gene hidAla4 for lethality, and the transformer gene intron from the Mediterranean fruit fly Ceratitis capitata for female-specific splicing. One strain carrying this construct eliminated 100% of the female offspring during embryogenesis and produced only males. However, homozygous females from these FK strains were not viable on a tetracycline-supplemented diet, possibly due to the basal expression of hidAla4. Potential improvements to the gene constructs and the use of such FK strains in an SIT program are discussed.
Why Flight Testing is an Important Step in Sterile Insect Technique
17547E. Ricciuti, Entomology Today, 2021-06-23 13:38:02.
Releasing hordes of sterilized male insects for unfruitful mating with females—a process known as the sterile insect technique (SIT)—is a proven process for combating many species of pests. Its success depends on sterile males dispersing widely enough to outcompete their wild counterparts and mate with enough females to reduce reproduction of a population. SIT has potential against the navel orangeworm (Amyelois transitella), a moth whose larvae decimates nut crops and, as its name implies, citrus, but scientists still are trying to figure out whether the idea will fly—literally. Researchers in California, where the moth’s larvae wreak havoc on almonds, walnuts, and pistachios, have conducted laboratory experimentsthat have revealed a potential glitch in dispersal ability that needs to be addressed before SIT can be effectively deployed against it. Their analysis is described in a report published this month in the Journal of Economic Entomology. The researchers, led by University of California-Riverside Ph.D. student Joshua Reger, examined the impact on the orangeworm of the same mass-rearing, sterilization, and transportation methods successfully used to combat the pink bollworm (Pectinophora gossypiella), a cotton pest. According to the new study, what works on the bollworm is iffy for the orangeworm, because the modus operandi seems to negatively impact flight performance, the key to dispersal. The researchers concluded that “the data from the current study demonstrate a substantial reduction in flight capacity in navel orangeworm, particularly males reared under the current conditions intended for use in a SIT program.”
Why Are Gates and Pentagon Releasing GMO Mosquitoes in Florida Keys?
17516F. W. Engdahl, LewRockwell.com, 2021-06-21 14:40:32.
On April 30 the Florida Keys Mosquito Control District and the Oxitec biotechnology company announced they will begin release of what will ultimately be some 750 million genetically manipulated or gene-edited Aedes Aegypti mosquitos using CRSPR gene editing technology. The Aedes Aegypti makes up only about 4% of the mosquito population in the Keys. The release is bitterly opposed by residents and environmental groups who demanded a referendum in last year’s election ballot, but which the Mosquito Control Board refused, curiously. Oxitec and the Board claim the release is to kill off the presence of the Aedes Aegypti mosquito which is believed to carry dengue fever, Zika and other diseases. The project, which sounds positive in the press statements, is alarming in many respects. First, the refusal to allow a citizen vote on the controversial GMO release. Second, there exists no cost-benefit analysis of the risks versus benefits of releasing millions of mosquitoes whose genetic traits are mutating in often unpredictable ways. Is it worth the risk that an ever more robust variety of mosquito will mutate from the project? No one can say. Traditional mosquito control techniques have worked well until now.
Genetically Modified Mosquitoes; ‘Truth Like Oil’ Novel
17487Here and Now, WBUR, 2021-06-16 15:10:42.
Florida Keys officials are working on a unique experiment: hatching thousands of genetically modified mosquitos and releasing them. Andrea Leal of the Florida Keys Mosquito Control District explains.
Temperature-Inducible Precision Guided Sterile Insect Technique
17447N. P. Kandul, J. Liu and O. S. Akbari, bioRxiv, 2021.06.14.448312. 2021-06-14 13:13:08.
Releases of sterile males are the gold standard for many insect population control programs, and precise sex sorting to remove females prior to male releases is essential to the success of these operations. To advance traditional methods for scaling the generation of sterile males, we previously described a CRISPR-mediated precision-guided sterile insect technique (pgSIT), in which Cas9 and gRNA strains are genetically crossed to generate sterile males for release. While effective at generating F1 sterile males, pgSIT requires a genetic cross between the two parental strains which requires maintenance and sexing of two strains in a factory. Therefore, to further advance pgSIT by removing this crossing step, here we describe a next-generation Temperature-Inducible pgSIT (TI-pgSIT) technology and demonstrate its proof-of-concept in Drosophila melanogaster. Importantly, we were able to develop a true-breeding strain for TI-pgSIT that eliminates the requirement for sex sorting, a feature that may help further automate production at scale.
Area-Wide Integrated Management of a Glossina palpalis gambiensis Population from the Niayes Area Of Senegal: A review of operational research in support of a phased conditional approach
25657M. J. B. Vreysen, M. T. Seck, B. Sall, A. G. Mbaye, M. Bassene, A. G. Fall, M. Lo and J. Bouyer, AREA-WIDE INTEGRATED PEST MANAGEMENT:, 2021-06-12 13:45:08.
In 2005, the Government of Senegal initiated a project entitled "Projet de lutte contre les glossines dans les Niayes" (Tsetse control project in the Niayes) with the aim of creating a zone free of Glossina palpalis gambiensis in that area. The project received technical and financial support from the International Atomic Energy Agency (IAEA), the Food and Agriculture Organization of the United Nations (FAO), the Centre de Cooperation Internationale en Recherche Agronomique pour le Developpement (CIRAD) and the US Department of State through the Peaceful Uses Initiative (PUI). It was implemented in the context of the Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC) following a phased conditional approach (PCA) that entails implementation in distinct phases, in which support to the next phase is conditional upon completion of all (or at least the majority of) activities in the previous phase. In the case of the tsetse project in Senegal, the PCA consisted of 4 phases: (1) commitment of all stakeholders and training, (2) baseline data collection, feasibility studies and strategy development, (3) preparatory pre-operational activities and (4) operational activities. This paper provides an overview of the main activities that were carried out within each phase, with emphasis on the operational research carried out in phases 2 and 3, that was instrumental in guiding the project's decision-making. Activities of phase 2 focused on the collection of entomological, veterinary, socio-economic and environmental baseline data, and a population genetics study that proved the isolated character of the G. p. gambiensis population of the Niayes. These data enabled the tsetse-infested area to be delimited to 1000 km(2), the impact of animal trypanosomosis on the farmers' welfare to be quantified (annual benefits of 2 million Euro in the tsetse-infested zone), and the formulation of an area-wide integrated pest management (AW-IPM) strategy that included a sterile insect (SIT) component to eradicate the isolated tsetse populations from the Niayes. In view of the extreme fragmentation of the remaining favourable habitat of the Niayes and the high human population density (peri-urban area), which excluded the possibility of using the Sequential Aerosol Technique, the IPM strategy that was selected comprised the suppression of the tsetse population with insecticide-impregnated traps/targets and the use of "pour-on" for cattle, followed by the release of sterile males to eliminate the remaining relic pockets. During phase 3, the pre-operational phase, a series of activities were carried out that were needed to implement the operational phase. These included the establishment of a colony of tsetse originating from the target area in Senegal, competitiveness studies between the sterile flies and those from the target area, development of transport methods for long-distance shipments of sterile male pupae, competitiveness of the sterile male flies after release in the target area, development of aerial release methods (including a new chilled adult release system) and development of a Maxent-based distribution model to guide the suppression, sterile male releases and monitoring of the eradication campaign. To be able to properly manage the eradication campaign in different phases, the entire target area was divided into 3 operational blocks. This paper demonstrates how, during the operational phase, scientific principles continued to guide the implementation process. The results to date are encouraging, i.e. the deployment of 269 insecticide-impregnated Vavoua traps in favourable habitat of Block 1 reduced the apparent density of the G. p. gambiensis population significantly (from 0.42 (SD 0.39) to 0.04 (SD 0.11) flies/trap/day). This was followed by the aerial release of sterile males that reduced the apparent density to zero after six months of releases. The last wild fly was trapped on August 9, 2012 in Block 1. In Block 2, during the suppression, the apparent fly density dropped from 1.24 (SD 1.23) to 0.005 (SD 0.017) flies/trap/day. Sterile male releases were initiated in February 2014 and expanded to cover the entire Block 2 in January 2015. The apparent fly density has so far been reduced to < 0.001 fly per trap per day until the end of 2018 and releases are still ongoing. The results of the campaign are discussed with respect to the "adaptive management approach" used, which was deemed critical for the success of the campaign.
The First Genetically Modified Mosquitoes Have Just Been Released in The US
17303Admin, Science World, 2021-06-11 11:14:27.
The biotech firm Oxitec has released its genetically modified mosquitoes in the Florida Keys, with the goal of suppressing wild, disease-carrying mosquito populations in the region. This is the first time genetically modified mosquitoes have been released in the US. Oxitec previously released its modified Aedes aegypti mosquitoes in Brazil, the Cayman Islands, Panama, and Malaysia, and the company reported that local A. aegypti populations fell by at least 90 percent in those locations, Live Science previously reported. A. aegypti can carry diseases such as Zika, dengue, chikungunya, and yellow fever, and releasing modified mosquitoes offers a way to control the population without using pesticides. Oxitec's modified mosquitoes, all male, have been engineered to carry a lethal gene; when the modified pests mate with wild female mosquitoes, the lethal gene gets passed on to their offspring.
Bill Gates Releasing Genetically Modified Mosquitoes in Florida? Here’s the Whole Story
17558M. Dapcevich, Snopes, 2021-06-03 14:44:33.
Bill Gates is not himself releasing mosquitoes into the wild. However, the Bill and Melinda Gates Foundation did award grants that funded biotech company Oxitec's work to develop genetically modified mosquitoes that may help reduce the spread of malaria and other mosquito-borne diseases. In April 2021, it was announced that approximately 150,000 mosquitoes would be released across six locations in Florida. Several state and federal agencies have been involved in the approval of this project. A multi-year research project to genetically modify Aedes aegypti, a mosquito species that is known to carry and transmit infectious diseases to humans, was slated to move from the lab to the fields of Texas and Florida in mid-2021. Under the project, thousands of A. aegypti were altered to make their reproduction more difficult, thus slowing and eventually preventing the spread of mosquito-borne illnesses like Zika, and dengue fever. But when the internet caught wind that Bill Gates may have been behind the project, posts circulated on social media that questioned the real motivation behind the project.
Mutant mosquitoes carrying ‘death gene’ released as ‘bio-engineered’ insects terrify
17185J. Caven, Daily Star, 2021-06-02 20:16:02.
Mutant mosquitoes which carry a ‘death gene’ have been released into the skies in a bid to curb diseases from spreading to humans. Tens of thousands of genetically modified male insects will mate with female Aedes aegypti mosquitoes, which transmit illnesses, in Florida Keys, US. Although the males don’t bite, they carry a gene which passes on and kills female offspring in the early larval stages. The pilot project aims to wipe out a generation of potential disease-carriers. Scientists say usual methods to stop the spread of disease from mosquitoes are becoming less effective due to resistance. But critics have slammed the programme and say they are being used as “guinea pigs in a sci-fi experiment”, the Times reported.
Genetically Altered Mosquitoes Target Deadly Dengue Fever and Zika
17174R. L. Hotz, Wall Street Journal, 2021-05-31 19:52:20.
Across the Florida Keys this week, newly hatched mosquitoes are swarming from damp flowerpots, waterlogged spare tires, trash cans and drainage ditches. In six neighborhoods, however, a change is buzzing in the air. Scientists have genetically modified thousands of these mosquitoes and, for the first time in the U.S., set them free to breed. These genetically engineered insects, known by their model number as OX5034, are a laboratory offshoot of the Aedes aegypti mosquito that transmits dengue, Zika and other infectious ills. After a decade of public debate and regulatory delays, these insects are being released by a U.K. biotechnology company called Oxitec. Using genetic-engineering techniques, the company altered the male mosquitoes to pass down a gene that makes females need a dash of the antibiotic tetracycline to survive. Without it, females that spread the disease die as larvae. Altered males, which don’t bite, seek out wild females to mate and spread the lethal trait to future generations. Gradually, more females die. The swarms dwindle and disappear, with no need for chemical insecticides.
Mosquitoes are deadly pests, genetically-modified mosquitoes could help stop disease
17127T. Browne, ClickOrlando, 2021-05-27 19:04:12.
Hearing the words “genetically modified mosquitoes” can sound like the plot for a science-fiction movie but Meredith Fenson, a native Floridian turned biological pest control specialist says, “mosquitoes are the world’s deadliest animal by far” and a study happening right now in the Florida Keys could help change the tide. Fenson works as the head of global public affairs for Oxitec and sat down with News 6 anchors Matt Austin and Ginger Gadsden on Florida’s Fourth Estate podcast to talk about how genetically modified mosquitoes work, concerns surrounding their release and Oxitec’s plans to release more in the future. Aedes Aegypti, the yellow fever mosquito, only makes up about 4% of the population in the Florida Keys but Fenson says they are responsible for virtually all the diseases spread from mosquitoes to humans. She says this includes Zika, dengue fever and Chikungunya.
A Novel Genetic Sexing Strain of Anastrepha Ludens for Cost-Effective Sterile Insect Technique Applications: Improved Genetic Stability and Rearing Efficiency
17125E. Ramírez-Santos, P. Rendon, G. Gouvi, A. Zacharopoulou, K. Bourtzis, C. Cáceres and K. Bloem, Insects, 12. 2021-05-27 19:00:07.
Anastrepha ludens (Loew) is one of the most destructive insect pests damaging several fruits of economic importance. The sterile insect technique (SIT) is used under an area-wide integrated pest management approach, to suppress these pest populations. Mass rearing facilities were initially established to produce sterile males of bi-sexual strains in support of SIT. The first genetic sexing strain (GSS) for A. ludens, Tapachula-7, based on pupal color dimorphism, was a key development since the release of males-only significantly increases the SIT efficiency. In this study, we document the development of a novel pupal color-based GSS. Twelve radiation-induced translocation lines were assessed as potential GSS in terms of recombination rates and rearing efficiency at a small scale. The best one, GUA10, was cytogenetically characterized: it was shown to carry a single translocation between the Y chromosome and chromosome 2, which is known to carry the black pupae marker. This GSS was further evaluated at medium and large scales regarding its genetic stability, productivity and quality versus Tapachula-7. GUA10 presented better genetic stability, fecundity, fertility, production efficiency, flying ability, and male mating, clear indicators that GUA10 GSS can significantly improve the efficacy and cost-effectiveness of SIT applications against this pest species.
Genetic engineering may help control disease-carrying mosquitoes
17123Anonymous, The Economist, 2021-05-26 18:56:02.
EVERY YEAR, hundreds of millions of people catch mosquito-borne diseases like malaria and dengue fever. Hundreds of thousands die. Drug treatments are imperfect. And, despite decades of effort, vaccines have, for many of these diseases, proved tricky to perfect. Better, then, to stop those infections happening in the first place, by exterminating—or at least suppressing—the mosquitoes that carry the diseases. In a paper just published in the Proceedings of the National Academy of Sciences, a team of researchers led by Craig Montell, of the University of California, Santa Barbara, describe how CRISPR-Cas9, a new and powerful genetic-engineering process, could help to do just that. Dr Montell and his colleagues used CRISPR to boost an existing control method called the sterile insect technique (SIT). This involves releasing lots of sterilised males into the wild. Females that mate with these males produce no offspring. Repeated releases can reduce populations dramatically. SIT has been used in North America to eliminate screwworm flies, an agricultural pest, and to suppress several species of crop-munching fruit flies.
Suppression of female fertility in Aedes aegypti with a CRISPR-targeted male-sterile mutation
17112J. Chen, J. Luo, Y. Wang, A. S. Gurav, M. Li, O. S. Akbari and C. Montell, Proceedings of the National Academy of Sciences, 118:e2105075118. 2021-05-26 18:33:06.
We introduced and characterized the impact on female fertility of an Ae. aegypti mutation that disrupts a gene that is specifically expressed in testes. We used CRISPR/Cas9 to generate a null mutation in the Ae. aegypti β2-tubulin (B2t) gene, which eliminates male fertility. When we allowed wild-type females to first mate with B2t mutant males, most of the females did not produce progeny even after being subsequently exposed to wild-type males. We also introduced B2t mutant and wild-type males simultaneously with wild-type females and found that a larger number of B2t mutant males relative to the wild-type males was effective in significantly suppressing female fertility. These results raise the possibility of employing B2t sterile males to improve the efficacy of SIT in suppressing populations of Ae. aegypti through repeated releases and thereby reduce the transmission of viruses by these invasive mosquitoes.All study data are included in the main text.
Oxitec takes on growing cattle tick challenges
17119Annonymous, The Cattle Site, 2021-05-25 18:50:21.
Oxitec Ltd, the leading developer of biological solutions to control pests that transmit disease, destroy crops and harm livestock, announced that the Bill & Melinda Gates Foundation has awarded a grant for a feasibility project to develop an Oxitec self-limiting solution for the disease-spreading cattle tick, Rhipicephalus microplus. As part of this grant, Oxitec will work with Clinglobal, one of the world’s largest science-based animal health service providers, incorporating Clinglobal’s deep and industry-leading expertise in animal vector control practices. As a species-specific approach to controlling pests, Oxitec’s Friendly technology platform offers a safe, environmentally friendly, and sustainable solution, proven to significantly reduce target pest populations to very low levels. A future Friendly cattle tick solution would reduce reliance on pesticides and offer cattle farmers a new way of protecting the health of their animals without the use of chemical pesticides.
Pest reduction with female killers and sterile males
17114L. Mertz, Good Fruit Grower, 2021-05-25 18:40:52.
New ways to fight spotted wing drosophila are in the works, thanks to new genetic engineering tools. These transgenic methods introduce new reproduction-hampering genes into male SWD, so that when they mate with females, the females either don’t have any young, or their female young die early in their development. The approach falls under the umbrella of sterile insect technique (SIT), which has traditionally been done with radiation to sterilize males that are then released to reduce pest reproduction. “SITs are thought of as green technologies, because they are species-specific, they have the advantage that the control agent is the insect itself, and they reduce the dependence on insecticides,” said Max Scott, a professor of entomology at North Carolina State University who is developing one of these approaches. He and his research group have incorporated a female-killing gene into male SWD. In a different approach, the San Diego company Agragene is advancing technology first developed by University of California, San Diego researchers. Here, the project makes use of an advanced gene-editing tool — called CRISPR — to add genes that both kill females and sterilize males. “We really do believe that our technology will bring a sea change to what’s going on out there,” said Gordon Alton, president and CEO of Agragene Inc. If all goes well, he anticipates growers will have access to the technology within two to three years
Sterilizing skeeters using CRISPR/Cas9
17117H. Tasoff, Phy Org, 2021-05-24 18:45:33.
Mosquitoes are one of humanity's greatest nemeses, estimated to spread infections to nearly 700 million people per year and cause more than one million deaths. UC Santa Barbara Distinguished Professor Craig Montell has made a breakthrough in one technique for controlling populations of Aedes aegypti, a mosquito that transmits dengue, yellow fever, Zika and other viruses. The study, published in the Proceedings of the National Academy of Sciences, documents the first use of CRISPR/Cas9 gene editing to target a specific gene tied to fertility in male mosquitoes. The researchers were then able to discern how this mutation can suppress the fertility of female mosquitoes. Montell and his coauthors were working to improve a vector-control practice called the sterile insect technique (SIT). To manage populations, scientists raise a lot of sterile male insects. They then release these males in numbers that overwhelm their wild counterparts. The idea is that females that mate with sterile males before finding a fertile one are themselves rendered infertile, thereby decreasing the size of the next generation. Repeating this technique several times has the potential to crash the population. What's more, because each generation is smaller than the last, releasing a similar number of sterile males has a stronger effect over time.
Florida Environmental Group Says GMO Mosquitoes Fall Short on Scientific Rigor
17079C. Drukier, NTD, 2021-05-20 15:01:00.
America’s first genetically modified mosquitoes are now buzzing around six locations in the Florida Keys as part of a pilot project. Developed by UK biotech company Oxitec, the bugs are designed to kill off the wild population of Aedes aegypti mosquitoes that carry diseases like Dengue fever, yellow fever, and the Zika virus. Some people who live in the Keys aren’t happy about being part of a science experiment. Barry Wray, executive director of the Florida Keys Environmental Coalition explains why his organization has been fighting the GMO bugs for the last decade.
Sterile Insect Technique: Successful Suppression of an Aedes aegypti Field Population in Cuba
17151R. Gato, Z. Menendez, E. Prieto, R. Argiles, M. Rodriguez, W. Baldoquin, Y. Hernandez, D. Perez, J. Anaya, I. Fuentes, C. Lorenzo, K. Gonzalez, Y. Campo and J. Bouyer, Insects, 12:13. 2021-05-18 10:40:50.
Here, we describe an open field trial to evaluate the effect of the release of irradiated male Ae. aegypti on a wild population. The pilot trial was carried out in a suburb of Havana and compared the mosquito population density before and after the intervention, in both untreated control and release areas. The wild population was monitored by an ovitrap network, recording frequency and density of eggs as well as their hatch rate. A significant amount of sterility was induced in the field population of the release area, as compared with the untreated control area. The ovitrap index and the mean number of eggs/trap declined dramatically after 12 and 5 weeks of releases, respectively. For the last 3 weeks, no eggs were collected in the treatment area, clearly indicating a significant suppression of the wild target population. We conclude that the sterile males released competed successfully and induced enough sterility to suppress the local Ae. aegypti population.
Genetically Modified Mosquitoes Take Flight to Fight Invasive Species in Florid
17073T. Machemer, Smithosonian Magazine, 2021-05-17 14:46:06.
In late April, the biotechnology company Oxitec placed blue-and-white hexagonal boxes on the properties of six private volunteers around the Florida Keys. After pouring in water, the genetically modified mosquito eggs inside activated and hatched. Now the first larvae have developed into full-grown male mosquitoes and taken flight, Susan Millis reports for Science News. About 12,000 of Oxitec’s male mosquitoes will fly out of the boxes each week for the next 12 weeks. Over several mosquito generations, Oxitec’s genetically modified Aedes aegypti could reduce the population of female mosquitoes—which bite and spread disease—and then lower the entire population in the Florida Keys in turn. The current trial marks the first time that genetically modified mosquitoes have been released to fly freely in the United States.
Genetically modified mosquitoes may help scientists swat dreaded midge
17057W. Jean, The Times, 2021-05-16 13:41:37.
Scotland’s bloodthirsty midges may finally meet their match thanks to revolutionary genetic manipulation techniques that could stop the pesky insects biting chunks out of the tourist industry. News that a British biotechnology company has created genetically modified non-biting mosquitoes in Florida to help curb dengue and yellow fever, and ultimately malaria, may give hope in the fight against the annual Scottish scourge. Oxford-based Oxitec and its American partners recently released genetically modified male mosquito larvae into the Florida Keys to control the wild, disease-carrying mosquito population rather than use pesticides. While midges share some characteristics with mosquitoes, Dr Simon Carpenter, a Pirbright Institute entomologist who was part of the team that built the first complete genome of the Highland biting midge, said the gene-editing process
British Firm Develops ‘Friendly’ Fall Armyworm To Save Crops
17176J. Choubey, Zenger, 2021-05-14 19:57:00.
The genetically modified fall armyworm, a pest that has invaded farms across Asia, Africa, and the Americas, has been developed by U.K-based biotechnology firm Oxitec to reduce the species’ population. The fall armyworm, or Spodoptera frugiperda, is a lepidopteran pest belonging to the family of butterflies and moths. It feeds on leaves, stems, and the reproductive parts of plants. The pest is causing significant damage to economically important cultivated grasses like maize, rice, sorghum, sugarcane, and wheat, along with 75 other crop species. Oxitec is collaborating with Bayer, a German multinational pharmaceutical and life sciences company, for the technology.
Bliotech firm behind CRISPR mosquitoes is working on other gene-hacked creatures
17217D. Robitzski, Futurism, 2021-05-14 16:08:11.
Brazil’s regulatory agency CTNBio gave Oxitec and Bayer the approval they needed to launch a field test of the gene-hacked armyworm — technically a caterpillar — on commercial crops, so there may be genetically altered bugs crawling across corn farms in the area soon. For years, Brazilian farmers have been trying to control fall armyworms with chemical pesticides. But as the pests grew to resist the sprays — which were already difficult to time in a way that actually impacted the nocturnal insect — they had to spray more and more harmful chemicals in the environment, according to Zenger‘s reporting. If Oxitec’s technology works — there’s reason to doubt that its similar mosquito tech does what the company claims — then that excessive pesticide spraying may be able to stop. “Our technology potentially reduces the need for additional pesticides in the long term,” Oxitec head of agricultural programs Neil Morrison said, according to Zenger. “Besides reducing populations of the pest, it also has the potential to slow the resistance development to insecticides and biotechnology enhanced crops.”
The U.S.’s first open-air genetically modified mosquitoes have taken flight
17041S. Milius, Science News, 2021-05-14 11:35:37.
The first genetically modified mosquitoes that will be allowed to fly free outdoors in the United States have started reaching the age for mating in the Florida Keys. In a test of the biotech company Oxitec’s GM male mosquitoes for pest control, these Aedes aegypti started growing from tiny eggs set out in toaster-sized, hexagonal boxes on suburban private properties in late April. On May 12, experiment monitors confirmed that males had matured enough to start flying off on their own to court American female mosquitoes. This short-term Florida experiment marks the first outdoor test in the United States of a strain of GM male mosquitoes as a highly targeted pest control strategy. This strain is engineered to shrink local populations of Ae. aegypti, a mosquito species that spreads dengue and Zika (SN: 7/29/16). That could start happening now that the GM mosquitoes have reached mating age because their genetics makes them such terrible choices as dads.
Use of genetically modifed mosquitoes to minimize the burden of diseases casused by mosquitoes in South Texas.
17016MDN Staff, MegaDoctor News, 2021-05-11 13:00:04.
Of the many species of mosquitoes, female Aedes aegypti is the primary vector that is responsible for transmission of several diseases and has been most extensively studied. The efforts of the World Health Organization and the Center for Disease Control and Prevention to prevent and/or control mosquito-borne illness have yielded success, but it remains a serious global challenge. More recently, several approaches to create transgenic mosquitoes with the ultimate objective of preventing and/or controlling mosquito-borne illness have undergone field studies. Infecting mosquitoes with different strains of Wolbachia resulted in the reduction of egg laying rates, transmission ability and shorter lifespan. Similarly, using genetic technology, a self-limiting strain of male mosquitoes (OX513A) when released in the field have shown an 81%-95% suppression of population of this strain as compared to adjacent no-release control field. These encouraging results prompted the issuance of authorization by the U.S. Environmental Protection Agency for the use of second generation genetically modified mosquitoes (OX5034) in Florida and Texas” said Sohail Rao, MD, MA, DPhil, President and Chief Executive Officer, DHR Health Institute for Research & Development. As the first-ever use of genetically modified mosquitoes in the United States, over 750 million OX5034 will be ultimately released in the Florida Keys an area devastated by mosquito-borne illnesses
Monster Mosquito–Why the Technology of Genetically Modified Mosquitoes is Dangerous and Should Be Stopped Worldwide
17001B. Dogra, counter currents, 2021-05-10 15:32:17.
After sparking controversy in other countries including India, the technology of genetically engineered mosquitoes is now leading to widespread protests in Florida USA. Here the biotechnology giant company Oxitec in collaboration with local officialdom is moving ahead with a pilot project to release millions of genetically engineered mosquitoes in Monroe County over a period of two years or so. The stated aim is to control the population of Aedes aegypti, a species that can carry both the dengue and the yellow fever virus. The idea is for genetically altered male, non-biting mosquitoes to mate with local , biting females , producing offspring that die at larval stage. Pointing out the inherent dangers of such technologies a spokesperson of Florida Key Environmental Coalition said that everyone should be writing to the White House to stop the release, at least until regulations to protect people are in place. Friends of the Earth has commented—scientists have raised concerns that genetically engineered mosquitoes could create hybrid wild mosquitoes which could worsen the spread of mosquito borne diseases and could be more resistant to insecticides than the original wild mosquitoes.
Florida releases genetically modified mosquitoes in hopes to reduce spread of disease
17011A. Fahim, Reuters, 2021-05-10 12:50:27.
Genetically modified mosquitoes have been released for the first time in the United States, taking flight in the Florida Keys in a pilot program intended to reduce the spread of deadly diseases such as dengue, yellow fever and the Zika virus.After an odyssey spanning more than a decade to secure regulatory approval, British-based biotechnology firm Oxitec, along with the Florida Keys Mosquito Control District (FKMCD)launched the project in hope of reducing the Aedes aegypti species that spread the diseases.While Oxitec and local authorities have high hopes for the program, local residents and environmental groups worry that not enough is known about the long-term effects of the new technology.Nevertheless, the Environmental Protection Agency granted an experimental use permit (EUP) to Oxitecon May 1.A half-dozen boxes containing the OX5034 mosquito created by Oxitec have been deployed in the Florida Keys, an archipelago stretching 120 miles (195 km) off the southern tip of the state.Only female Aedes aegypti bite and spread disease, so Oxitec has created males that pass on a gene that kills female offspring before they mature. Their male offspring then continue mating and passing on the altered gene.
Why Florida is releasing genetically modified mosquitoes
16999M. Murphy, The Telegraph, 2021-05-09 15:19:45.
The thousands of lab-grown mosquitoes hatching in humid gardens across Florida’s tropical Key West next week will be blissfully ignorant of the controversy they have caused. Billboards have already begun appearing near busy motorways in protest of their arrival, with one splashed with the words “risky, unnecessary, unwanted” aside a giant picture of the blood-thirsty insect. “The word ‘genetically modified’ scares people,” says Douglas Mader, a local vet and newspaper columnist living in the Lower Keys. “They think oh my god, they’re releasing genetically modified organisms (GMOs) and they are going to bite me and I’m going to turn into a zombie”. The creatures are the creation of Oxitec, a Bill Gates-backed biotechnology company based in Abingdon, Oxfordshire. Grey Frandsen, its chief executive, and around 20 scientists at Oxitec’s labs, have made it their mission to stop the spread of diseases such as dengue, Zika and malaria by controlling mosquitoes’ reproduction.
Genetically Modified Mosquitoes Have Come to the U.S. Will They Work?
16996A. de la Garza, TIME, 2021-05-09 15:13:05.
“Our Mosquito Project Takes Flight,” reads a baby-blue billboard off US-1 in the Florida Keys, alongside an image of an insect tracing a path in the shape of a heart. Sponsored by the local mosquito control board and U.K.-based biotech firm Oxitec, the ad promotes a contentious plan to release millions of genetically modified Aedes aegypti mosquitoes here to test a new method of bioengineered pest control. It’s the first-ever such experiment in the United States, and one that has turned this chain of sun-soaked island communities into a battleground over scientific truth, government authority, and humanity’s right to modify nature. Even this bit of roadside signage is contested. Four months ago, the billboard carried a different ad, paid for by the Coalition Against GMO Mosquitoes, an organization with the mission of stopping releases of the genetically modified insects in the U.S., “WARNING!!!,” it read then, “GENETICALLY MODIFIED MOSQUITOES TO BE RELEASED IN THE KEYS!!” That release began in late April, when, after a decade of planning, regulatory review and debate, Oxitec workers and local mosquito control personnel added water to a dozen plastic boxes containing the company’s “Friendly™” mosquito eggs in six locations around the Keys, triggering their hatching process. Oxitec’s Aedes aegypti mosquitoes—which the U.S. Environmental Protection Agency (EPA) approved for use last year—are genetically modified to include a “self-limiting” gene that produces a fatal protein. The mosquitoes are raised in a laboratory in the presence of tetracycline, an antibiotic that prevents the added gene from activating. The mosquitoes’ eggs are then left to hatch in the wild, without the antibiotic. The gene kills immature egg-laying females—the only ones that bite—but the males reach maturity, mate with wild females, and pass on their faulty gene. Then their female progeny die, causing the bloodsuckers’ population to crash.
Bill Gates finances the creation of transgenic mosquitoes
16992Explica.co, explica, 2021-05-07 15:03:11.
Male mosquitoes (they do not bite. They feed on nectar, not blood) from Oxitec will emerge from release boxes placed in six locations in the Florida Keys to mate with local female mosquitoes (they do bite. They do feed on blood). The female offspring from these encounters cannot survive, and the Aedes aegypti population will be controlled in this way.. The Aedes aegypti mosquito makes up about four percent of the mosquito population in the Keys. The project has the approval of the Environmental Protection Agency (EPA) and the Florida Department of Agriculture and Consumer Services (FDACS) and the collaboration of the Florida Keys Mosquito Control District (FKMCD). In 2021, the United States expects the release of 750 million transgenic mosquitoes. “An important part of the FKMCD’s mission is to protect the residents of the Florida Keys from the disease-transmitting mosquito, Aedes aegypti. As we are seeing the development of resistance to some of our current control methods, we need new tools to fight this mosquito. And given the unique ecosystem we live in, those tools must be safe, environmentally friendly and specific. That’s why we collaborate with Oxitec on this project. With the full approval of the US EPA and from the Florida Department of Agriculture and Consumer Services, and with the support of the US Centers for Disease Control and an independent advisory board, we are pleased to announce that this project will be underway soon, ”says Andrea Leal, executive director of the FKMCD.
Genetically Modified Mosquitoes Released In US For First Time To Combat Disease
16985J. Van Zijl, IFL Science, 2021-05-06 16:11:16.
A landmark project, spearheaded by the biotechnology company, Oxitec, has released genetically modified mosquitos in the Florida Keys. This marks the first time that genetically modified mosquitos have been released into the wild in the US. The reason: to combat the Aedes aegypti mosquito species responsible for spreading mosquito-borne diseases such as dengue and Zika in the region. Aedes aegypti only accounts for about 4 percent of the total mosquito population in Florida keys – however, it is responsible for almost all mosquito-borne diseases to humans. Current methods to control the species, such as spraying or fogging chemical insecticides, have failed due to the species becoming resistant. So an alternative solution was needed.
Genetically Modified Mosquitoes Released In Florida ‘Jurassic Park Experiment’
16978D. Richardson, UNILAD, 2021-05-06 15:58:18.
Mosquitos are not only annoying but they can carry disease in their bites. In response to this, a company called Oxitec has genetically modified male mosquitos to pass on a killswitch to females. It is hoped that these genetically modified pests will help stop the transmission of deadly diseases, including yellow fever, dengue and Zika virus. The Florida Keys project, which was greenlit by the US Environment Protection Agency in May 2020, has approved the release of 750 million modified mosquitos. However, at the moment only 144,000 will be released during a three-month trial period. Nonetheless, some people in the trial areas are concerned.
Gravitas: Genetically modified mosquitoes arrive in Florida
16962P. Sharma, WION, 2021-05-06 15:03:25.
Genetically engineered mosquitoes have arrived in U.S. 20 million 'modified mosquitoes' will be released in Florida to help prevent Dengue. But, Florida residents fear a 'mosquito apocalypse'
Reengineered mosquitoes released in Florida pilot program
17021S. W. Tan, The Washington Times, 2021-05-06 13:12:32.
Genetically engineered mosquitoes have been released in the U.S. for the first time in the Florida Keys, with hopes of quelling wild, disease-carrying mosquito populations in the region. British-based biotech firm Oxitec genetically engineered Aedes aegypti non-biting male mosquitoes to carry a lethal gene that gets passed onto their offspring when they mate with wild biting female mosquitoes. The offspring are unable to survive, hence controlling the population of disease-carrying species, according to the Florida Keys Mosquito Control District (FKMCD), one of the entities that approved the firm’s project. Release boxes containing the genetically engineered male mosquitoes were placed in six locations last week — two on Cudjoe Key, one on Ramrod Key and three on Vaca Key — with thousands starting to emerge this month. Around 12,000 mosquitoes are expected to emerge each week for about 12 weeks.
First genetically modified mosquitoes released in US
16972N. Lanese, LiveScience, 2021-05-05 15:42:05.
The biotech firm Oxitec has released its genetically modified mosquitoes in the Florida Keys, with the goal of suppressing wild, disease-carrying mosquito populations in the region. This is the first time genetically modified mosquitoes have been released in the U.S. Oxitec previously released its modified Aedes aegypti mosquitoes in Brazil, the Cayman Islands, Panama and Malaysia, and the company reported that local A. aegypti populations fell by at least 90% in those locations, Live Science previously reported. A. aegypti can carry diseases such as Zika, dengue, chikungunya and yellow fever, and releasing modified mosquitoes offers a way to control the population without using pesticides. Oxitec's modified mosquitoes, all male, have been engineered to carry a lethal gene; when the modified pests mate with wild female mosquitoes, the lethal gene gets passed on to their offspring. Though the gene does not affect the males' survival, it prevents female offspring from building an essential protein and thus causes them to die before reaching maturity. Only female mosquitoes bite people (male mosquitoes exclusively drink nectar), so the modified mosquitoes and their surviving male offspring can't pass diseases to humans.
Bill Gates-backed startup releases millions of genetically modified mosquitoes
16952ENTREPRENEUR STAFF, Entrepreneur, 2021-05-04 20:35:48.
The British company Oxitec released a cloud of hundreds of millions of genetically modified mosquitoes to study how to control their reproduction and thus stop the spread of dengue, Zika, malaria, etc. As reported by Axios , the company, which is funded by the Bill and Melinda Gates Foundation , released the mosquitoes a week ago from the Florida Keys. In a statement, Oxitec explained that this experiment seeks to study ways to stop the reproduction of Aedes aegypti , the main transmitters of potentially fatal diseases. Why are Oxitec mosquitoes different? According to the company , the males in their insect cloud have a modified gene, called OX5034, that restricts the survival of the females they mate with. Thus, mosquitoes will not grow large enough to bite humans (only females consume blood; males feed on nectar). Oxitec noted that this species only represents 4% of the mosquito population in Florida, but it is the most disease-transmitting species. The startup has already released millions of modified insects around the world, including in Brazil and the Cayman Islands.
First US Field Test of GM Mosquitoes Begins in Florida
16950C. Wilcox, The Scientist, 2021-05-04 20:30:49.
he first US field test of genetically modified mosquitoes for population control has begun in Florida. Approximately 144,000 mosquitoes engineered by the UK-based biotech firm Oxitec are to be expected to be set free over the next three months, the first of up to 750 million approved for release over the next two years by the US Environmental Protection Agency. The trial aims to test whether the mosquitoes are effective at reducing populations of invasive Aedes aegypti, a species that can transmit dangerous diseases to people. The Florida Keys Mosquito Control District, which has partnered with Oxitec, has said this species makes up only 4 percent of the mosquito community in the Keys but is responsible for nearly all disease transmission and has become increasingly resistant to available pesticides, Nature reports. According to Oxitec, the modified mosquitoes are all male and carry a gene that makes female mosquitoes dependent on an antibiotic not available in the animals’ environment, thereby killing all of the male’s female offspring. Adult mosquitoes only live for a few weeks, and just the females bite, so the firm expects its modified males can spread the female-killing insert through the population and drastically reduce the number of potential disease vectors in the region. If successful, the mosquitoes could be used in place of pesticides in control efforts. A small but vocal group of Florida residents that has opposed the “mutant mosquitoes” from the get-go are continuing to seek legal action to stop it, CNN reports. Key Largo resident Mara Daly tells CNN she hopes “civil unrest happens,” and suggests residents could have their communities sprayed with pesticides in an effort to “opt out” of the trial.
The first transgenic mosquitoes were releaseed in the United States.
16947D. Davis, Prudent Press Agency, 2021-05-04 20:19:07.
After a decade of fighting for regulatory approval and public acceptance, the biotech company has released GMO mosquitoes outdoors in the United States for the first time. The experiment, which began this week in the Florida Keys, despite objections from some local critics, is testing a method for suppressing populations of wild Aedes aegypti mosquitoes, which can transmit diseases such as Zika, dengue fever, chikungunya and yellow fever mosquitoes. Oxitec, the UK-based company Abingdon that developed mosquitoes, has previously tested the insects in the field in Brazil, Panama, the Cayman Islands and Malaysia. But so far, due to a tortuous series of regulatory decisions and Florida residents’ disapproval (see “Long Road”), no GM mosquitoes have been tested in the United States, although the country had previously allowed evidence of a GM diamond. Moth (Plutella xylostella) in New York and pink worm (Pectinophora gossypiella) in Arizona, both developed by Oxitec. “When something new and revolutionary comes along, people’s immediate reaction is to say, ‘Wait,’” says Anthony James, a molecular biologist specializing in mosquito bioengineers at the University of California, Irvine. [Oxitec] Was able to conduct a trial on the ground in the United States a big problem. “
The Bill Gates Corporation, Backed by Bill Gates, Releases Thousands of Genetically Modified Mosquitoes
16975T. Meeks, Aviation Analysis, 2021-05-04 15:50:15.
British company Oxitec has launched transgenic mosquitoes in the Florida Keys, in the United States, to study how to control their reproduction and thus limit the spread of chronic diseases transmitted by insects such as dengue fever and the Zika virus. The company, funded by the Bill & Melinda Gates Foundation, announced the placement of its confined release funds, non-release funds, and quality control funds this week in six locations: two in Cudjoe Key, one in Ramrod Key, and three in Vaca Key. Why is the Oxitec mosquito different? According to the company, the males in its insect cloud carry a modified gene called OX5034, which restricts the survival of the females they mate with. As of early next month, fewer than 12,000 mosquitoes are expected to appear per week for about 12 weeks. Untreated comparison sites will be controlled with mosquito traps at Key Colony Beach, Little Torch Key, and Summerland Key. “We started looking at this a decade ago because we were in the middle of an outbreak of dengue fever in the Florida Keys,” Andrea Lyell, executive director of the Florida Keys area for mosquito control, said during a videoconference. “So we are very excited to further this partnership, and work with both Oxitec and members of the community.” Last year the Keys authorities approved the pilot project with mosquitoes Aedes aegyptiShe is not a Florida native. This insect transmits many diseases to humans, especially in the Keys island chain, where dozens of dengue cases were recorded last year.
Sterile Insect Technique Programme against Mediterranean Fruit Fly in the Valencian Community (Spain)
16965I. Plá, J. García de Oteyza, C. Tur, M. Á. Martínez, M. C. Laurín, E. Alonso, M. Martínez, Á. Martín, R. Sanchis, M. C. Navarro, M. T. Navarro, R. Argilés, M. Briasco, Ó. Dembilio and V. Dalmau, Insects, 12. 2021-05-04 15:09:26.
The Mediterranean fruit fly, Ceratitis capitata (Wied.), is an endemic pest in fruit-growing areas of the Spanish Mediterranean coast. In the Valencian Community, it represents a serious problem in the cultivation of citrus and numerous species of fruit, such as peach, cherry, apricot, persimmon, etc. For over 50 years, the Department of Agriculture of Valencia has led, promoted, and carried out a C. capitata control programme to protect crops, especially citrus fruits, because this community is the largest national producer and the leading region for fresh citrus exports in the world. Traditionally, pest control has been based on the use of insecticides. However, a reduction of more than 90% of a target wild population was achieved in the frame of a pilot integrated pest management (IPM) project based on the sterile insect technique (SIT), which was implemented from 2003 to 2006. Based on this successful result, in 2007 the Department of Agriculture of Valencia initiated an area-wide integrated pest management (AW-IPM) programme for the suppression of C. capitata, using the SIT as the primary control method. Complementary activities are implemented periodically in hotspots and during different time periods depending on the pest population dynamics. As a result, there has been a reduction of more than 90% in the use of insecticides by aerial means to control C. capitata, as well as a growth trend in exports of citrus and fresh fruits from the Valencian Community in recent years. This paper provides a historical review of the Valencian programme and briefly describes how technological innovations and decision-making tools have contributed to programme efficiency.
Next gen insect control
16960E. Unglesbee, Progressive Farmer, 2021-05-04 14:58:12.
Dubbed "self-limiting" insects by their makers, a UK-based biotechnology company called Oxitec, these insects are genetically modified (GM) with an inserted gene that permits only male offspring to survive. Once released into a pest community, the GM insects gradually lower the population, accomplishing a new type of pest control. Then, rather politely, they die off themselves. "After we stop releasing the self-limiting males, the gene declines in a population over a short period of time and within a few generations, disappears," Neil Morrison, head of agriculture programs for Oxitec, told DTN. "It's a gene that prevents survival of half its carriers -- the females -- so it's essentially programmed to decline and disappear quite rapidly." Sound too sci-fi to be real? It's actually happening right now, in the Florida Keys. After gaining EPA and state regulatory approval for the project last year, Oxitec is working with the Florida Keys Mosquito Control District to deploy the country's first largescale release of Oxitec's self-limiting Aedes aegypti mosquitoes.
Stable isotopes for reliable identification of wild and mass-reared Queensland fruit flies in sterile insect technique programs
17031B. Mainali, A. S. Andrew, P. W. Taylor and P. Rempoulakis, Journal of Pest Science, 14. 2021-05-04 11:12:25.
Queensland fruit fly is one of the most economically important horticultural pests in Australia. Sterile insect technique (SIT) is now being reconsidered and upscaled to combat this pest so reliable discrimination of released sterile Q-flies from wild flies in monitoring traps is important for effective SIT operations. Stable isotopes provide a permanent chemical marker to discriminate sterile and wild flies when dye marking is unclear. In this study, we compared the isotopic ratios of carbon and nitrogen between Q-flies reared on different larval diets and wild flies collected from diverse locations in Australia and New Caledonia. Finally, we conducted a release-recapture study to corroborate differences in stable isotope C and N ratios in laboratory-reared and wild Q-flies. The delta N-15 values obtained from wild and laboratory Q-flies showed high variability that is likely related to the food source of the larval and/or adult stage and do not offer an effective means to discriminate between sterile and wild Q-flies. The delta C-13 values of examined wild Q-flies ranged from - 27.46 to - 24.37 parts per thousand VPDB, whereas those from laboratory-reared, released and recaptured Q-flies ranged from - 25.73 to - 19.26 parts per thousand VPDB. Differences in delta C-13 values resulted in 100% correct classification of wild flies and 96.88% correct classification of released flies. Measurements of intrinsic delta C-13 values offer a precise tool to discriminate between sterile and wild Q-flies in SIT programs, regardless of the composition of the larval or adult pre-release diets.
Genetically modified mosquitos: Biohacking for disease prevention.
16941D. Maloney, HACKADAY, 2021-05-03 15:02:07.
Mosquito control is basically a numbers game, stacked in their favor. Since each female lays 100 to 200 eggs in a clutch, in wet climates, mosquitos are simply too prolific to get ahead of using standard means. Coupled with collateral damage to the environment — draining wetlands carries potentially huge impacts on a wide range of species, as does the indiscriminate use of pesticides — the search for new control methods with less harmful ecological side-effects has led to research into genetic methods of reducing mosquito populations. The idea of genetically engineering insects is nothing new. The fruit fly Drosophila melanogaster has had its genome extensively modified for over 100 years, first using standard mating and crossing techniques and later using transgenic methods to insert, delete, and edit genes. The result has been a wealth of knowledge about how the genetics of higher organisms work, as well as models for human diseases ranging from diabetes to Parkinson’s. But in general, transgenic fruit flies are simply model organisms destined to live and die in the lab. The concept of building a genetically modified insect for release into the wild is fairly new. Oxitec, the company behind the planned releases of transgenic mosquitos in Florida, has been working on the genetic control of a range of pest insect species since it was founded in 2002. They are currently on their second generation of genetically modified Aedes aegypti mosquitos, which is the insect that will soon be tested in Florida. The mosquito, dubbed OX5034, has been genetically engineered to be self-limiting. Both male and female OX5034 mosquitos carry a synthetic gene that is lethal only to females. The plan is to release OX5034 male mosquitos into a wild population where they’ll breed with unmodified females. These females will take a blood meal and lay eggs that carry the synthetic gene. Only the male eggs in the clutch will develop into adulthood; the females will all die during the larval and pupal stage, which will eventually reduce the number of blood meals taken and the potential for disease spread.
First genetically modified mosquitoes released in the United States
16939E. Waltz, Nature, 2021-05-03 14:56:33.
After a decade of fighting for regulatory approval and public acceptance, a biotechnology firm has released genetically engineered mosquitoes into the open air in the United States for the first time. The experiment, launched this week in the Florida Keys — over the objections of some local critics — tests a method for suppressing populations of wild Aedes aegypti mosquitoes, which can carry diseases such as Zika, dengue, chikungunya and yellow fever. Oxitec, the firm based in Abingdon, UK, that developed the mosquitoes, has previously field-tested the insects in Brazil, Panama, the Cayman Islands and Malaysia. But until now, owing to a circuitous series of regulatory decisions and pushback from Florida residents (see ‘A long road’), no genetically engineered mosquito had been trialled in the United States — even though the country previously allowed tests of a genetically engineered diamondback moth (Plutella xylostella) in New York and an engineered pink bollworm (Pectinophora gossypiella) in Arizona, both developed by Oxitec. “When something new and revolutionary comes along, the immediate reaction of a lot of people is to say: ‘Wait.’,” says Anthony James, a molecular biologist focused on bioengineered mosquitoes at the University of California, Irvine. “So the fact that [Oxitec] was able to get the trial on the ground in the United States is a big deal.”
Oxitec releases first genetically modified mosquitoes in U.S.
16928J. Knutson, Axios, 2021-05-01 15:46:09.
Oxitec, a British startup determined to prevent instances of mosquito-borne disease, released thousands of genetically modified mosquito eggs in the Florida Keys this week as part of a test approved by the Environmental Protection Agency and Florida's agriculture department. Why it matters: It marks the first release of genetically modified mosquitoes in the U.S. and has some locals worried about how this will impact the broader ecosystem, according to CNN. How it works: Oxitec expects to target Aedes aegypti, an invasive species of mosquito that carries several dangerous diseases like yellow fever, dengue and Zika virus.
Armyworm meets Friendly moth
17066M. Francisco, Nature Biotechnology, 39:532-532. 2021-05-01 14:11:25.
The fall armyworm moth, a pest so named for its caterpillar’s invasive and destructive behavior, may now have to contend with a ‘Friendly’ foe. UK-based Oxitec and agbiotech giant Bayer have jointly developed a genetically modified variety to combat the fall armyworm (Spodoptera frugiperda), an insect pest causing severe destruction to corn, rice and sorghum crops in more than 100 countries. Brazil has approved field trials of the GM ‘Friendly’ fall armyworm moths. The technology, originally developed at Oxford University, uses male self-limiting fall armyworm moths. When males are released into infested areas, the moths mate with wild females, but as they produce no female offspring in the next generation, this reduces the population of crop-eating caterpillars. The approach is species specific, is self-limiting in the environment, and has no impact on beneficial insects such as bees. Oxitec has successfully used the technology with mosquitoes to control dengue and Zika in Brazil, and is currently releasing Friendly mosquitoes in the Florida Keys as part of a US Environmental Protection Agency trial. Though some groups remain opposed to the technology, most experts agree that GMOs must be part of an integrated pest management solution, in addition to rotating crops, encouraging the growth of a pest’s natural predators, and using pesticides selectively to mitigate resistance buildup.
Genetically modified mosquitoes have landed in the Keys. Here’s what you need to know
16918G. Filosa, Miami Herald, 2021-05-01 13:54:49.
More than 20 million genetically modified mosquitoes are coming to the Florida Keys this year, in a landmark project by British biotech company Oxitec and Monroe County’s Mosquito Control District. This mosquito control method hasn’t been used in the U.S. before. It’s a pilot program and the first trial began over the past week. The project is aimed at reducing the population of the invasive Aedes aegypti, which carries diseases like Zika. This is the first time in the country that the U.S. Environmental Protection Agency has issued the “experimental use permit” for this method.
Genetically modified mosquitoes | Connect the Dots
16905thv11, THV11, 2021-04-30 17:56:23.
This is a local TV story from Arkansas of the Oxitec trial being conducted in Florida.
‘Home to GMO Mosquitoes?!’ Florida Unleashes a Billion Lab Grown Mosquitoes
16925Anonymous, B and T MAGAZINE, 2021-04-30 15:40:06.
Up to a billion genetically engineered mosquitoes are going to be released in the Florida Keys—but locals are having none of it, with billboards erected saying ‘no!’ to the damned blood suckers. The genetically-modified mosquitoes, known as the OX5034, were made in a laboratory in London by British biotech firm Oxitec, in a bid to kill-off a species in the Florida Keys that carries dengue fever, Zika virus, and yellow fever. It comes after more than 7,300 dengue cases were reported in the US in the past decade, Vice reports. While most were contracted outside America, 71 were transmitted in Florida, according to the CDC.
The Release of 1 Billion Exterminator Mosquitoes Has Begun
16922D. Noor, Gizmodo, 2021-04-30 15:32:45.
Tens of thousands of male mosquitoes are descending on the Florida Keys. But these are no ordinary mosquitoes: They’re genetically modified, and they were planted around the state on purpose. It’s part of a plan to curb disease by releasing 1 billion mosquitoes across two states—but it’s giving some folks the heeby jeebies. Workers placed boxes of mosquitoes’ eggs—two on Cudjoe Key, one on Ramrod Key and three on Vaca Key—on Thursday, and expect them to hatch in about a week. They’ll repeat the process over the coming months, releasing 12,000 of the bugs per week for 12 weeks. That’s 144,000 mosquitoes overall—gross. The project marks the first time GMO mosquitoes have ever been released in the U.S., was launched by the Florida Keys Mosquito Control District (FKMCD) with the private British firm biotech Oxitec. It’s an attempt to curb the spread of dengue, Zika and yellow fever.
First-ever US release of genetically modified mosquitoes begins in Florida Keys
16920S. LaMotte, CNN, 2021-04-30 15:27:44.
The first release of genetically modified mosquitoes in the United States began this week in the Florida Keys -- the culmination of a decade-long effort by local mosquito control authorities to see if a genetically modified organism is a viable alternative to spraying insecticides in the region.For the first 12-week phase, blue-and-white boxes containing about 12,000 GMO eggs developed by a US-owned, British-based company called Oxitec have been placed in six small areas of Ramrod Key, Cudjoe Key and Vaca Key. When water is added, the mosquitoes hatch, mature and enter the environment over the next week or so. A small, vocal group of Florida Key residents have fought the release of what they call "mutant mosquitoes" since the project was announced -- and they are incensed. "Our opposition has been long and strong," said Barry Wray, the executive director of the Florida Keys Environmental Coalition. "We live here, this our home, and they're forcing this down people's throats." "The only thing you can do legally at this point is stand in your yard with an insect fogger," said Mara Daly, a resident of Key Largo, Florida, who has fought the release for eight years. "You can't touch a box, but you can fog the s**t out of your own yard if you don't want to be a part of the trial."
The first genetically modified mosquitoes released in the U.S. to buzz in the Florida Keys
16897K. Weintraub, USA Today, 2021-04-29 17:37:24.
On Thursday morning, workers from a British company placed basketball-sized cardboard boxes into six yards in the Florida Keys. Then they added water. In a week or so, 12,000 male Aedes aegypti mosquitoes will – one by one – begin buzzing out of each box, the first genetically modified mosquitoes to be released in the United States. Local officials argue the trial is necessary at a time when pesticides are increasingly ineffective against these dangerous pests. A 2016 vote on the project claimed a solid majority of support in most of the surrounding counties. "At the end of the day, our hope is to be able to control this mosquito more efficiently and keep our population below any sort of disease transmission threshold," said Andrea Leal, executive director of the Florida Keys Mosquito District. "Our toolbox for Aedes aegypti control is shrinking, unfortunately, and that's making us think outside of the box."
A Billion Lab-Grown Mosquitos Are Being Released and People Are Freaking Out
16895V. Kipnis, Vice, 2021-04-29 17:08:03.
On Thursday afternoon, six Florida Keys residents will walk out into their yards and set out aquamarine cardboard boxes filled with mosquito larvae. Then, water will be poured into the containers. For the next ten days, as the mosquitoes grow into adults, their neighbors will be waiting to see what happens next. That’s because these aren’t just any mosquitoes: These are genetically-modified organisms, known as the OX5034, and they were made in a laboratory in London. Under a two-year Experimental Use Permit approved by the EPA, the British biotech firm Oxitec has been green-lit to release over 1 billion genetically modified mosquitoes across 6,600 acres in Florida and Texas. For their pilot project, they’re focusing on the lower Florida Keys, where in the coming 12 weeks, they plan to release 144,000 non-biting male mosquitoes from six different locations—making this the first time ever that a genetically-engineered mosquito will be let out into an open ecosystem in the United States.
The mosquito-bite fight begins
16883F. Billingsley, Click2Houston, 2021-04-29 15:10:43.
Anyone who thought February’s freeze would kill all the mosquitos is biting up the wrong leg. They are back and, seemingly so, with a vengeance (did surviving just make them stronger, one wonders?). In Florida this week, an interesting and controversial fight against the bite begins after more than a decade of getting there. The company Oxitec will be releasing 144,000 Genetically Modified Mosquitoes in the Florida Keys designed to fight the mosquito population. Did you ever take the antibiotic tetracycline? I took it to fight acne as a kid but it treats lots of other bacterial infections. Oxitec has engineered all their mosquitoes with a gene that makes only the females depend on tetracycline. Without it, the females die and it’s the females that bite. So all the eggs from the engineered mosquitoes will be shipped to Florida and when they hatch, the engineered female mosquitoes won’t have any tetracycline and they are toast.
Nearly 144K GMO Mosquitoes to be Released in South Florida: What We Know
16902J. Prigeon, 6 South Florida, 2021-04-28 17:46:54.
Nearly 144,000 genetically modified mosquitoes will be released in South Florida this week as part of an effort to reduce the population disease-carrying mosquitoes. The landmark release of GMO insects marks the beginning of the U.S.-approved program to control the number of Aedes aegypti mosquitoes in the area. The project will place boxes loaded with Oxitec’s non-biting male mosquitoes in six areas around the Florida Keys to mate with biting female mosquitoes. As a result of the encounters, the female offspring will not survive and – hopefully – will reduce the dangerous mosquito's population in the area.
Nation’s first trial of genetically modified mosquitoes starts in Florida Keys
16889S. Brock, TODAY, 2021-04-28 15:15:04.
To control the population of potentially disease-spreading mosquitoes, a controversial project is getting underway in the Florida Keys, highlighted by the release of even more mosquitoes that have been genetically modified. NBC’s Sam Brock reports for TODAY from Miami.
Florida Unleashing Thousands of Mosquitoes
16886Anonymous, The Weather Channel, 2021-04-28 15:11:10.
Florida will begin releasing thousands of genetically modified mosquitoes in the Keys this week to combat diseases like Zika and dengue. But the government’s green light has some residents seeing red.
GMO mosquitoes to be released in Florida Keys
16880NBC News, WRCBtv, 2021-04-28 15:02:40.
Florida will begin releasing genetically modified mosquitoes this week as part of its efforts to control one of the disease-spreading species of the biting insect. The state will release almost 144,000 nonbiting male mosquitoes in the coming weeks engineered by the British firm Oxitec that are meant to mate with biting females, with any resulting female offspring unable to survive. The project was approved after years of public comment and official review. "As we are seeing development of resistance to some of our current control methods, we are in need of new tools to combat this mosquito," Andrea Leal, executive director of the Florida Keys Mosquito Control District said in a press release. The project is meant to control the population of the Aedes aegypti mosquito, which can spread dengue fever, Zika virus and yellow fever, as well as heartworm to pets and animals.
Nearly 150,000 Gene-Hacked Mosquitoes to Be Unleashed in Florida
16878S. Kim, Newsweek, 2021-04-28 14:58:55.
Nearly 150,000 mosquitoes that have been genetically modified by Oxitec, a biotechnology company based in the U.K., will be released across parts of Monroe County's Florida Keys region starting this week. The release is part of an experiment to help combat a disease-transmitting local mosquito population (the Aedes aegypti mosquito species) that is responsible for "virtually all mosquito-borne diseases transmitted to humans" such as dengue, Zika and yellow fever, the company says. Speaking to Newsweek, a spokesperson for Oxitec said: "We are releasing 12,000 [mosquitoes] per week for 12 weeks," which equates to a total of 144,000 mosquitoes, the spokesperson added. The experiment—a collaboration between the Florida Keys Mosquito Control District (FKMCD) and Oxitec—received approval from the U.S. Environmental Protection Agency (EPA) and the Florida Department of Agriculture and Consumer Services (FDACS). It is also supported by the U.S. Centers for Disease Control and Prevention as well as an independent advisory board, Oxitec says.
Genetically modified mosquito larvae to be released in Florida Keys
16869E. Helmore, The Guardian, 2021-04-28 14:13:40.
The Florida Keys will this week see the release of genetically modified, non-biting male mosquito larvae as part of a controversial program designed to curb the spread of insect-borne diseases such as dengue, Zika and yellow fever. The Florida Keys Mosquito Control District and British firm biotech Oxitec announced last week that 12,000 of the invasive Aedes aegypti mosquito species are expected to emerge each week for twelve weeks from six locations: two on Cudjoe Key, one on Ramrod Key and three on Vaca Key. US researchers seek citizen scientists as billions of Brood X cicadas set to emerge Eventually it is planned that hundreds of millions of the mosquitoes might be released. Oxitec’s non-biting male mosquitoes will mate with the local biting female mosquitoes and since the female offspring cannot themselves survive to reproduce, the population of Aedes aegypti is subsequently controlled. According to the CDC, the genetically modified mosquitoes carry two types of genes: a fluorescent marker gene that glows under a special red light, and a self-limiting gene that prevents female mosquito offspring from surviving to adulthood.
Florida set to release swarms of GMO mosquitoes as residents decry ‘criminal experiment’ by Bill Gates-backed biotech
16866rt com, rt com, 2021-04-28 14:04:30.
A plan to release thousands of genetically modified mosquitoes in an effort to combat disease in the Florida Keys has triggered dire concerns among locals, some saying the “criminal” experiment will turn them into guinea pigs. Spearheaded by the Florida Keys Mosquito Control District (FKMCD) and Oxitec, a British biotech firm that’s received backing from the Bill and Melinda Gates Foundation, the project aims to turn the first swarms of gene-edited bugs loose into the Keys starting sometime this week, the two bodies announced in a joint statement. For the first leg of the plan, set to be expanded later, mosquito boxes will be placed at six locations, which over 12 weeks will release around 144,000 Aedes aegypti mosquitoes, a species most closely linked with transmitting illnesses such as dengue, Zika and yellow fever. If all goes according to plan, the male, non-biting bugs will mate with local biting females, whose female offspring are programmed to die off, helping to control the Aedes aegypti population and reduce the spread of disease. While the particular species makes up only about 4% of the overall population in the Keys, it is behind “virtually all” mosquito-borne diseases passed to humans, as well as some that are transmitted to animals, such as heartworm, according to Oxitec.
“Maskandi experience”: exploring the use of a cultural song for community engagement in preparation for a pilot Sterile Insect Technique release programme for malaria vector control in KwaZulu-Natal Province, South Africa 2019
17029P. N. Manana, S. Jewett, J. Zikhali, D. Dlamini, N. Mabaso, Z. Mlambo, R. Ngobese and G. Munhenga, Malaria Journal, 20:11. 2021-04-28 11:06:19.
Background An assessment of the Sterile Insect Technique (SIT) as a complementary malaria vector control tool, is at an advanced stage in South Africa. The technique involves the release of laboratory-reared sterilized male mosquitoes of the major malaria vector Anopheles arabiensis, raising social, ethical and regulatory concerns. Therefore, its implementation largely depends on community participation and acceptance. Against this background, it is critical that robust and effective community strategies are developed. This study describes the development of a cultural song to engage the community and increase awareness on SIT and malaria control in KwaZulu-Natal, South Africa. Methods An exploratory concurrent mixed-methods study was conducted to get opinions about the effectiveness of a cultural song developed to engage communities and increase acceptability of the SIT technology. Two self-administered surveys (expert and community) were conducted. Additionally, more in depth opinions of the song and its effectiveness in conveying the intended information were investigated through three community dialogue sessions with community members in the study area. Results A total of 40 experts and 54 community members participated in the survey. Four themes were identified in relation to the appropriateness and effectiveness of the song, with a fifth theme focused on recommendations for adaptations. Overall, the song was well received with the audience finding it entertaining and informative. Responses to unstructured questions posed after the song showed an increase in the knowledge on malaria transmission and SIT technology. In particular, the explanation that male mosquitoes do not bite allayed anxiety and fears about the SIT technology. Conclusion The song was deemed both culturally appropriate and informative in engaging community members about the SIT technology. It proved useful in promoting health messages and conveying SIT technology as a complementary malaria vector control tool. With minor adaptations, the song has potential as an area-wide community engagement tool in areas targeted for sterile male releases.
BUZZ OFF Florida residents blast pest control ‘TERRORISTS’ over plans to unleash a BILLION mutant mosquitoes in the Keys
16857J. Bentley-York, The SUN, 2021-04-27 20:46:15.
The areas Mosquito Control District (FKMCD) are set to release the gene hacked ‘fraken-squitoes' in a bid to fight insect-borne viruses like yellow fever. A BILLION mutant mosquitoes are set to be released in the Keys to fight insect-borne viruses like yellow fever Florida pest control chiefs have been branded “terrorists” over the plans. The trial is set to begin this week, seeing a first phase of up to 144,000 modified mosquitoes released over the next 12 weeks. The project aims to reduce the numbers of Aedes aegypti species which are known for carrying diseases including dengue, chikungunya, zika and yellow fever. The male mosquitoes, developed by British biotech company Oxitect, do not bite, and will be introduced in small areas in a select number of neighborhoods in the Monroe area. However, Florida residents are calling on the US Environmental Protection Agency (EPA) to end "this live experiment" as they blasted the organisation as “terrorists.” Barry Wray of the Florida Keys Environmental Coalition said: “People here in Florida do not consent to the genetically engineered mosquitoes or to being human experiments.”
Florida to release a billion genetically modified mosquitoes and people are worried
16871B. Robinson, indy100, 2021-04-27 14:19:58.
It sounds like the pitch for a horror movie, but Florida’s about to release up to a billion genetically modified mosquitoes in the Keys. What could go wrong? Florida residents and environmentalists are already voicing their concerns after state officials and Oxitec, a biotechnology a UK-based biotechnology company, announced plans to release the critters over a two year period in Monroe County, in the Florida Keys section of the state. But why? In a press release from Friends of the Earth, they state that the project attempts to reduce the number of Aedes aegypti, one of the many species of mosquitoes that carry infectious diseases such as Yellow Fever and Zika.
Thousands of genetically modified mosquitoes being released in Florida
16863T. Lapin, New York Post, 2021-04-27 13:58:39.
Thousands of genetically modified mosquitoes have begun to be released in Florida this week as part of an effort to combat a disease-spreading species of the insect. The buzzy project, from British biotech company Oxitec, aims to curb the population of Aedes aegypti mosquitoes, which can spread diseases such as Zika and dengue fever, The Miami Herald reported. The project aims to have genetically modified male mosquitoes mate with non-modified females, which are the ones that bite. A so-called “death mechanism” would then act to prevent any resulting female offspring from surviving.
Halt This Nightmare’: Alarm as Florida Set to Begin Release of Genetically Engineered Mosquitoes
16861J. Johnson, Common Dreams, 2021-04-26 20:59:02.
Environmentalists and Florida residents voiced concern and outrage Monday as state government officials and the biotechnology giant Oxitec announced plans to move ahead this week with a pilot project that involves releasing up to a billion genetically engineered mosquitoes in Monroe County over a two-year period. Presented by local authorities as an effort to control the population of Aedes aegypti—a mosquito species that can carry both the dengue and yellow fever virus—critics warn that the effort's supposed benefits and its potential negative consequences have not been sufficiently studied. Responding to news that the first boxes of genetically modified mosquitos are set to be placed in six locations in Monroe County this week, Friends of the Earth noted in a press release that "scientists have raised concerns that GE mosquitoes could create hybrid wild mosquitoes which could worsen the spread of mosquito-borne diseases and could be more resistant to insecticides than the original wild mosquitoes."
Florida residents claim ‘pest control trial’ that will release up to a BILLION genetically engineered mosquitos in the Keys to reduce species carrying diseases is ‘TERRORISM’
16859S. Liberatore, Daily Mail, 2021-04-26 20:54:47.
The Florida Keys will soon be buzzing with close to a billion 'fraken-squitoes' – gene-hacked mosquitoes aimed at eradicating a disease carrying mosquito. The Florida Keys Mosquito Control District (FKMCD) and Oxitec, a British biotech company, are starting the first-ever U.S. release of genetically engineered (GE) Aedes aegypti mosquitoes this week, which will see up to a billion over a two-year period. The project aims to reduce the numbers of Aedes aegypti, one of several mosquito species that can carry diseases including dengue, chikungunya, Zika and yellow fever. Floridians, however, are calling on the US Environmental Protection Agency (EPA) to end 'this live experiment' saying they are being subjected to terrorism by the FKMCD.
Coalition Against GMO Mosquito Condemns Release of Genetically Engineered Mosquitoes
16853GMO Free USA, 3BL CSRwire, 2021-04-26 20:40:26.
Despite a decade of community opposition, the experimental release of genetically engineered mosquitoes begins today in the Florida Keys. British biotech corporation, Oxitec, in collaboration with the Florida Keys Mosquito Control District, plans to release up to a billion genetically engineered mosquitoes in two phases. GMO Free USA and the Coalition Against GMO Mosquitoes condemn the uncontrolled release and are airing radio spots to educate Florida Keys residents about the health and environmental risks. This unprecedented mass release of a genetically engineered insect is the first of its kind in the United States and many Florida Keys residents remain unaware. The Coalition Against GMO Mosquitoes recently launched an educational website, StopGMM.com, and sponsored a local billboard to increase public awareness and galvanize opposition. The new radio spot will run daily on multiple stations. Oxitec and the FKMCD have failed to provide sufficient answers to the most pressing questions posed by concerned residents. Some residents have reached out to government officials at the EPA, in Congress and the White House to request intervention to halt the experiment until thorough research is conducted.
Nation’s First Trial Of Genetically Modified Mosquitoes Starts In Florida Keys
16851N. Klingener, WLRN, 2021-04-26 20:35:50.
Boxes containing the eggs of genetically modified Aedes aegypti mosquitoes, water and a little food are being placed in six locations in the Lower and Middle Keys this week — in a trial that will be the first of its kind in the United States. The genetic modification is intended so that female offspring won't survive. Female mosquitoes are the ones that bite and can transmit diseases like dengue and zika. The genetically modified males are supposed to breed with wild females — and then their female offspring won't survive, either. Andrea Leal is in charge of the Florida Keys Mosquito Control District. The district has been working with the British firm Oxitec for more than a decade, since a 2009-10 outbreak of dengue fever in Key West.
Genetically-engineered mosquitoes set for release in Florida Keys: Science offers tool to fight Zika, dengue, malaria but critics claim it’s unnecessary and potentially dangerous
16808J. Musto, Genetic Literacy Project, 2021-04-22 16:02:53.
U.K.-based biotechnology company Oxitec has partnered with the Florida Keys Mosquito Control District in an effort to control the invasive and disease-spreading female Aedes aegypti mosquitoes in the region. Oxitec’s [genetically modified] male mosquitoes — which don’t bite, unlike the recently-discovered yellow fever-carrying Aedes scapularis mosquitoes — will be introduced in small areas in a select number of neighborhoods between mile markers 10 and 93 in the Keys. In recent reporting from Undark, the non-profit digital science magazine notes that Oxitec had been proposing an experimental release in the Keys for years and that it had been rejected before in both Key Haven and Key West — though some residents in surrounding areas voted in support of the release.
Development of Sterile Insect Technique for Control of the European Grapevine Moth, Lobesia botrana, in Urban Areas of Chile
16849G. S. Simmons, M. C. Salazar Sepulveda, E. A. Fuentes Barrios, M. Idalsoaga Villegas, R. E. Medina Jimenez, A. R. Garrido Jerez, R. Henderson and H. Donoso Riffo, Insects, 12. 2021-04-22 13:20:22.
The European grapevine moth, a Palearctic pest, was first detected in the Americas in 2008. Its establishment in Chile presented production and export issues for grapes and other fruits, and a national control campaign was launched. Urban areas next to agricultural production areas were recognized as a challenge for effective control. In 2015, a SIT laboratory was established in Arica, Chile to evaluate its potential for urban control. Progress included the development and evaluation of artificial diets, a mass-rearing of 75,000 moths/week, confirmation of 150 Gy as an operational dose for inherited sterility, and releases of sterile moths in a 25 ha urban area next to fruit production areas. Season-long releases demonstrated that high overflooding ratios were achieved early in the season but decreased with a large increase in the wild moth population. Sterile moth quality was consistently high, and moths were observed living in the field up to 10 days and dispersing up to 800 m. Recommendations for further development of the SIT include conducting cage and field studies to evaluate overflooding ratios and mating competitiveness, measuring of infestation densities in release and no-release areas, and conducting trials to evaluate combining SIT with compatible integrated pest management (IPM) tactics such as fruit stripping and use of mating disruption.
UK biotech firm’s 750 mn GM mosquitoes will mate with females off Florida, sow a deadly gene
16819S. Ramesh, The Print, 2021-04-20 16:27:48.
Oxitec, a UK-based biotechnology company, plans to release genetically modified mosquitoes in the Florida Keys islands off the US this month as part of a trial to curb mosquito-borne diseases like dengue and the one caused by the Zika virus. This is the latest genetic engineering experiment targeting mosquitoes that is aimed at tackling diseases that continue to kill thousands every year — an approach that has critics as well as backers. Only females of mosquitoes bite, while males feed on all nectar. The mosquitoes Oxitec plans to release will all be male, carrying a protein that will kill all their female offspring. The exact locations where the mosquitoes will be released have not been made public. The objective over time is to reduce the population of the Aedes aegypti mosquito, which spreads both the above-mentioned diseases as well as chikungunya and yellow fever. Mosquito populations in Florida are believed to have grown resistant to a common group of insecticides, prompting worries.
Estimates of the population size and dispersal range of Anopheles arabiensis in Northern KwaZulu-Natal, South Africa: implications for a planned pilot programme to release sterile male mosquitoes
17062M. L. Kaiser, O. R. Wood, D. Damiens, B. D. Brooke, L. L. Koekemoer and G. Munhenga, Parasites and Vectors, 14:18. 2021-04-19 13:57:18.
The Anopheles gambiae complex and An. funestus group species made up the majority of wild collections along with other anophelines. The An. arabiensis population size was estimated to be between 550 and 9500 males per hectare depending on time of year, weather conditions and method used. Average dispersal distance of marked males ranged from 58 to 86 m. Marked males were found in swarms with wild males, indicating that laboratory-reared males are able to locate and participate in mating swarms. Conclusions It was logistically feasible to conduct mark-release-recapture studies at the current scale. The population size estimates obtained may provide a guideline for the initial number of males to use for a pending SIT pilot trial. It is promising for future SIT trials that laboratory-reared marked males participated in natural swarms, appearing at the right place at the right time.
Florida to release genetically modified mosquitoes to fight disease
16812K. Jones, WND, 2021-04-17 16:07:26.
A biotechnology company will soon release genetically modified mosquitoes in certain areas of the Florida Keys in order to combat infectious diseases spread by the parasitic insects.The findings could lead to a new method for combating the spread of diseases such as the Zika virus and dengue fever, according to experts. Both diseases are commonly attributed to mosquito bites in humans.Fox News reported that a strain of mosquitoes developed by a United Kingdom-based company called Oxitec -- partnered with the Keys' Mosquito Control District -- will soon be released into a select number of neighborhoods in Florida. The aim of the experimental program is to control the population of the female Aedes aegypti mosquitoes which make life insufferable for many residents of the Keys.
Dengue fever and Zika The first genetically modified mosquitoes are released in Florida to fight disease
16805M. Woolridge, The Daily Guardian, 2021-04-17 15:46:01.
Biotechnology Corporation Oxitec Planning to release transgenic mosquitoes in Florida Keys. The company says its technology aims to combat dengue fever, a deadly disease transmitted by mosquitoes Aedes aegyptiIn addition to other diseases such as Zika.According to Who is the And the Centers for Disease Control and Prevention in the United States. However, some neighbors are against releasing this transgenic mosquito because they fear that they will become so Guinea pigs. Oxitec Attempts to release genetically modified mosquitoes from 2011But it was always getting delayed due to discussions of places and some scholars. Despite this, the Florida Keys Mosquito Control District agreed to Exam, Which will take place at various locations at Keys.
Oxitec Receives Landmark Biosafety Approval for New Fall Armyworm Control Solution
16810Oxitec, Oxitec, 2021-04-15 16:03:00.
Approval of Oxitec’s Friendly™ fall armyworm technology by the Brazilian government’s regulatory agency CTNBio confirms that it is safe for people, animals and the environment. Oxitec’s Friendly™ fall armyworm is a new, safe, and sustainable solution to one of the world’s most devastating crop pests. CTNBio’s decision is a significant step towards deployment on commercial corn fields in Brazil. This is the world’s first commercial biosafety approval of an agricultural Friendly™ insect solution, following the regulatory approval in Brazil for Oxitec’s Friendly™ Aedes aegypti mosquito in 2020
Scientists are now playing god with mosquitoes
16794M. Wehner, BGR, 2021-04-15 13:13:24.
Preventing illnesses in humans is a high priority for scientists that devote their lives to finding cures and techniques that keep people healthy, but sometimes a plan comes along that is so wild it can cause even the most devoted science fans to furrow their brow. In Florida, dengue fever regularly sickens over 100 people per year, and many of those individuals that contracted the virus are believed to have received it locally via mosquitos. Now, in what can only be described as the real-life equivalent of a made-for-TV sci-fi movie, scientists in Florida are prepared to unleash a swarm of genetically modified mosquitoes that will hopefully cut down on the number of the biting insects and, as a result, lower the numbers of mosquito-borne illnesses. The company behind the “OX5034” modified mosquitos is called Oxitec, and while it’s gained approval from the Environmental Protection Agency, there are still plenty of critics that fear unforeseen consequences.
The Insect Pest Control Laboratory of the Joint FAO/IAEA Programme: Ten Years (2010–2020) of Research and Development, Achievements and Challenges in Support of the Sterile Insect Technique
16702M. J. B. Vreysen, A. M. M. Abd-Alla, K. Bourtzis, J. Bouyer, C. Caceres, C. de Beer, D. Oliveira Carvalho, H. Maiga, W. Mamai, K. Nikolouli, H. Yamada and R. Pereira, Insects, 12. 2021-04-13 15:29:17.
The Joint FAO/IAEA Centre (formerly called Division) of Nuclear Techniques in Food and Agriculture was established in 1964 and its accompanying laboratories in 1961. One of its subprograms deals with insect pest control, and has the mandate to develop and implement the sterile insect technique (SIT) for selected key insect pests, with the goal of reducing the use of insecticides, reducing animal and crop losses, protecting the environment, facilitating international trade in agricultural commodities and improving human health.
First GMO mosquitoes to be released in the Florida Keys
16688T. White, UNDARK, 2021-04-12 15:18:49.
Oxitec says its technology will combat dengue fever, a potentially life-threatening disease, and other mosquito-borne viruses — such as Zika — mainly transmitted by the Aedes aegypti mosquito. While there have been more than 7,300 dengue cases reported in the United States between 2010 and 2020, a majority are contracted in Asia and the Caribbean, according to the U.S. Centers for Disease Control and Prevention. In Florida, however, there were 41 travel-related cases in 2020, compared with 71 cases that were transmitted locally. Native mosquitoes in Florida are increasingly resistant to the most common form of control — insecticide — and scientists say they need new and better techniques to control the insects and the diseases they carry. “There aren’t any other tools that we have. Mosquito nets don’t work. Vaccines are under development but need to be fully efficacious,” says Michael Bonsall, a mathematical biologist at the University of Oxford, who is not affiliated with Oxitec but has collaborated with the company in the past, and who worked with the World Health Organization to produce a GM mosquito-testing framework.
Introduction of a cold sensitivity-conferring mutation into the RTA-Bddsx hybrid system of Bactrocera dorsalis for establishment of a thermally controllable homozygous line
17327S. M. Dai, C. Y. Huang and C. Chang, Pest Management Science, 7. 2021-04-10 14:40:01.
BACKGROUND For efficient control of the economically important fruit pest Bactrocera dorsalis, a hybrid system combining ricin toxicity and sex-related alternative splicing of the doublesex gene has been developed. This system exhibits the expected female-specific lethal effect; however, the transgenic females do not survive, making it difficult to raise stable homozygous lines. Since modification of ricin toxin A chain (RTA) through a single-residue change (Gly(212) > Arg(212)) leads to cold-sensitive posttranslational repression of its toxicity, we utilized this unique property to obtain RTA-Bddsx females that survive at low temperature for line maintenance. RESULTS In transient expression experiments using embryonic injection, two groups treated with RTAcs-derived DNA (LERQcs and RTAcs) exhibited temperature-dependent effects. The toxicity was higher at 29 degrees C than at 18 degrees C. The proportion of males was close to 50% at 18 degrees C in all the tested groups except LERQcs-treated flies, which exhibited a high proportion of males (over 70%) at 29 degrees C. The results indicate the cold-sensitive responses of RTA and further suggest a female-specific lethal effect. Subsequently, 14 putative RTAcs-Bddsx transgenic Ds-Red(+) G(1) males were identified, and female-specific lethal effects were observed in Ds-Red(+) G(2) and G(3) lines under cultivation at 29 degrees C but not at 18 degrees C. The male ratio can be increased to up to 95% in G(3) line 001, indicating that RTAcs functions well in B. dorsalis. CONCLUSION The improved RTAcs-Bddsx system with conditional toxicity represents a novel and promising step toward the practical control of B. dorsalis.
Determining the Sterilization Doses under Hypoxia for the Novel Black Pupae Genetic Sexing Strain of Anastrepha fraterculus (Diptera, Tephritidae)
16672P. D. Giustina, T. Mastrangelo, S. Ahmad, G. Mascarin and C. Caceres, Insects, 12. 2021-03-30 13:38:24.
Our study reports for the first time the dose-sterility response under hypoxia for two different A. fraterculus strains. The pupae were derived from a bisexual strain (a Brazilian-1 population) and a recently developed genetic sexing strain (GSS-89). Two hours prior to irradiation, pupae were transferred to sealed glass bottles and irradiated when oxygen concentration was below 3%. Four types of crosses with nonirradiated flies of the bisexual strain were set to assess sterility for each radiation dose. For males from both strains, Weibull dose–response curves between radiation doses and the proportion of egg hatch, egg-to-pupa recovery, and recovery of adults were determined. The GSS males revealed high sterility/mortality levels compared to males from the bisexual strain at doses < 40 Gy, but a dose of 74 Gy reduced egg hatch by 99% regardless of the male strain and was considered the sterilizing dose. The fertility of irradiated females was severely affected even at low doses under hypoxia.
Village hears from experts as genetic-mosquito release experiment nears.
16678J. McCarthy, KEYSWEEKLY, 2021-03-26 14:56:47.
On March 18, Islamorada Village Council heard from several independent scientists who discussed information and issues behind the genetically modified mosquitoes for population and disease suppression. The scientists collectively said they’re neither for nor against the release. A representative from the Florida Keys Mosquito Control District and one from Oxitec responded following the presentation. Fred Gould, professor of North Carolina State’s Department of Entomology and Plant Pathology, briefly explained the strain of mosquitoes (OX5034) set for release. He said he was involved with another strain of genetically modified mosquitoes in development in 2010 when a field case study was conducted in Mexico. “In the laboratory, it turned out the male mosquitoes flew fine and mated well. But in the real environment, they weren’t as strong as the wild type mosquitoes and they basically had 3% of the matings. Instead of having half the matings, they had very few,” he said. Gould went on to say that this is also shown in work by Oxitec in Brazil, where it turns out that the genetic mosquitoes “are not very fit.” “It would take 30 of them, at least, to be equal to an individual wild type in terms of how many matings you have,” he said. “When you’re thinking about that, you have to recognize you have to release a lot of mosquitoes in order to have any activity. I just want to bring that home to you that it goes up and down as to what that percent fitness is, and we don’t know what that’ll look like in Florida. “Will it work? I want to say it might work just fine,” he continued. “There’s a chance that they’ll be doing these releases and it won’t be a simple thing.”
Sterile Insect Technique in an Integrated Vector Management Program against Tiger Mosquito Aedes albopictus in the Valencia Region (Spain): Operating Procedures and Quality Control Parameters
16663C. Tur, D. Almenar, S. Benlloch-Navarro, R. Argilés-Herrero, M. Zacarés, V. Dalmau and I. Pla, Insects, 12. 2021-03-23 14:20:04.
The Agriculture Department of the Valencian Region is promoting an ongoing pilot project to evaluate the efficacy of an integrated vector management program (IVM) based on the use of the SIT as the main method of control. The laboratory studies for evaluating the entomological efficacy of SIT through the phased conditional testing process recommended by World Health Organization and the International Atomic Energy Agency (WHO-IAEA) are addressed. This study describes the routine operating procedures and quality control parameters for the medium-scale rearing of sterile male A. albopictus. More than 15 million sterile males have been produced and released in an area of 80 ha between 2018 and 2020. Of the initial L1 larvae, we recovered 17.2% of male pupae after sex sorting to be sterilized and released on the field, while the rest of the pupae remained available to maintain the rearing colony. The residual percentage of females after sex sorting was on average 0.17%. The obtained values in terms of production and quality control as well as the proposed rearing methodology can be useful for designing a medium-scale mosquito-rearing pipeline.
When More is Less: Mosquito Population Suppression Using Sterile, Incompatible and Genetically Modified Male Mosquitoes
18708S. L. Dobson, Journal of Medical Entomology, 58:1980-1986. 2021-03-11 13:50:08.
The current review of the Sterile Insect Technique (SIT) is motivated by new technologies and the recent renaissance of male release field trials, which is driving an evolution in mosquito control and regulation. Practitioners that are releasing male mosquitoes would do well to learn from past successes and failures, including political and public engagement complications. With examples that include nuanced integrations of the different technologies, e.g., combinations of Wolbachia and irradiation, it is critical that scientists understand and communicate accurately about the technologies, including their evolving management by different regulatory agencies in the USA. Some male release approaches are considered ‘pesticides’ and regulated by federal and state agencies, while other male release approaches are unregulated. It is important to consider how the new technologies fit with the more ‘traditional’ chemical applications of adulticides and larvicides. The economics of male release programs are substantially different from traditional control costs, which can be a challenge to their adoption by abatement districts. However, there is substantial need to overcome these complications and challenges, because the problem with invasive mosquitoes grows ever worse with factors that include insecticide resistance, globalization and climate change.
Mosquito anxiety prompts query from congressman
16592T. Java, Keynews.com, 2021-03-10 20:09:26.
Anxiety among some residents over the pending release of hundreds of millions of genetically modified mosquitoes next month in undisclosed locations throughout the Florida Keys has prompted Congressman Carlos Gimenez to seek answers from the U.S. Environmental Protection Agency. The Florida Keys Mosquito Control District and Oxitec, a British-based biotech company, plan to release genetically modified Aedes aegypti mosquitoes in selected neighborhoods between mile markers 10 and 93 as a way to control the wild population of the disease-carrying pest. This is the first experiment of its kind in the U.S.
Eliminating Mosquitoes with Precision Guided Sterile Males
16563M. Li, T. Yang, M. Bui, S. Gamez, T. Wise, N. P. Kandul, J. Liu, L. Alcantara, H. Lee, J. R. Edula, R. Raban, Y. Zhan, Y. Wang, N. DeBeaubien, J. Chen, H. M. Sanchez C, J. B. Bennett, I. Antoshechkin, C. Montell, J. M. Marshall and O. S. Akbari, bioRxiv, 2021.03.05.434167. 2021-03-06 20:07:26.
Here we develop a molecular genetic control system termed precision guided sterile insect technique (pgSIT) in Aedes aegypti. PgSIT uses a simple CRISPR-based approach to generate sterile males that are deployable at any life stage. Supported by mathematical models, we empirically demonstrate that released pgSIT males can compete, suppress, and eliminate mosquitoes in multigenerational population cages. This platform technology could be used in the field, and adapted to many vectors, for controlling wild populations to curtail disease in a safe, confinable, and reversible manner.
Engineered expression of the invertebrate-specific scorpion toxin AaHIT reduces adult longevity and female fecundity in the diamondback moth Plutella xylostella
16653T. Harvey-Samuel, X. Xu, E. Lovett, T. Dafa'alla, A. Walker, V. C. Norman, R. Carter, J. Teal, L. Akilan, P. T. Leftwich, C. M. Reitmayer, H. A. Siddiqui and L. Alphey, Pest Management Science, 2021-03-04 17:21:00.
To increase the flexibility of future genetic pest management systems in the diamondback moth, we aimed to assess the use of a non-cell-autonomous, invertebrate-specific, neurotoxic effector ? the scorpion toxin AaHIT. This AaHIT effector was designed to be secreted by expressing cells, potentially leading to effects on distant cells, specifically neuromuscular junctions. We demonstrated the feasibility of using non-cell-autonomous effectors within a GPM context for the first time in Lepidoptera, one of the most economically damaging orders of insects. These findings provide a framework for extending this system to other pest Lepidoptera and to other secreted effectors.
Tensions rise as GM mosquito release nears in Florida Keys
16520T. O'Hara, Keynews.com, 2021-03-03 20:29:44.
Tensions seem to be rising as a planned release of genetically modified mosquitoes nears. The British-based biotech company Oxitec plans to release genetically modified Aedes aegypti mosquitoes in the Florida Keys sometime after April, but has yet to disclose exact locations in the Keys or a date.
Florida Keys moves forward with genetically modified mosquitoes
16524H. Vela, local10.com, 2021-03-03 18:08:13.
The feared GMO mosquitoes are not going away. Opponents of the technology fear the date of the release in the Florida Keys is getting closer, and they are not ready for the possible repercussions of the experiment. The fight over whether or not to release genetically modified mosquitoes in Monroe County has been going on for almost a decade. Barry Wray said the mosquito control team’s contractor wants to deliver the first batch in April. Wray, the executive director of the Florida Keys Environmental Coalition, said he doesn’t believe there is enough evidence to prove that the technology is safe. He said there is a need for independent scientific investigation. “You don’t really know what the long-term outcomes could be or how to quantify those risks, and if you can’t do that scientifically, then you don’t know how to responsibly mitigate it or detect if something is going awry,” Wray said.
Knowledge, Attitude, and Practices Survey in Greece before the Implementation of Sterile Insect Technique against Aedes albopictus
16661A. Stefopoulou, S. L. LaDeau, N. Syrigou, G. Balatsos, V. Karras, I. Lytra, E. Boukouvala, D. P. Papachristos, P. G. Milonas, A. Kapranas, P. Vahamidis and A. Michaelakis, Insects, 12. 2021-03-02 13:52:16.
A KAP tool was used to shed light on the knowledge, practices, and attitudes of local community members in order to better prepare and motivate participation in household mosquito control and to assess current understanding of SIT. Each household also received specific information about mosquito source habitat in their own yards at the time of the initial KAP survey. These household data were complemented by standardized mosquito trapping in the municipality. Our findings indicate that citizens’ attitude toward SIT ranged from indecisive to fully supportive, while 77.5% of the respondents agreed that the SIT has many advantages over chemical control methods. Furthermore, the results demonstrate that using the door-to-door campaign as an intervention and prerelease method before SIT can suppress the initial mosquito population and potentially improve its efficacy. Lastly, we show that the presence of local municipality officials during door-to-door visits was associated with increased willingness from the residents to participate in the intervention.
When and where will millions of mosquitoes be released? Here are details for Florida Keys
16485D. Goodhue, Miami Herald, 2021-02-25 21:09:17.
The Florida Keys Mosquito Control District announced this week a wide and vague planned range of deployment for the lab-designed mosquitoes — neighborhoods from mile marker 10 to 93. The trial is being conducted by British biotech company Oxitec. It’s a method approved by the U.S. Environmental Protection Agency, the state of Florida, and the mosquito control district’s five-member board, to try to eradicate or significantly reduce the local population of Aedes aegypti mosquitoes.
Sterile Insect Technique: Lessons From the Past
18706M. Q. Benedict, Journal of Medical Entomology, 58:1974-1979. 2021-02-25 13:35:08.
When E.F. Knipling conceived of the release of sexually sterile insects to suppress wild populations, he laid down several fundamental qualities that characterized suitable target species—some of which mosquitoes generally violate—including high reproductive rates and large population numbers. Regardless of this, their global importance in public health has led numerous research teams to attempt to use the mosquito sterile insect technique against several species. Because of the degree of financial commitment required for suppression programs, most releases have consisted of preliminary investigations of male performance, population characteristics, and production methods. Those that have accomplished suppression provide important insights regarding the challenges of production, dispersal, and immigration. Insights gained from these studies remain relevant today, regardless of the genetic control technology being applied. In this article, I highlight studies that were notable for the insights that were gained, the intrinsic difficulties that mosquitoes present, and synthesize these into recommendations for successful applications of the sterile insect technique and newer technologies to mosquitoes.
Company uses engineered mosquitoes to prevent diseases
16514N. Herzog and D. Niesel, The Daily News, 2021-02-24 21:47:32.
It’s amazing how many serious infectious diseases are transmitted by insects like ticks, fleas and mosquitoes. These are called vector-borne diseases, which are responsible for significant human suffering and economic disruption. Mosquitoes are responsible for the spread of many viral diseases including Zika, malaria, West Nile virus, Eastern Equine Encephalitis virus and many others. For the majority of these diseases, we don’t have effective therapeutics or vaccines to treat those that get sick. One approach to control these diseases is to eliminate or reduce the arthropod or insect vector populations using broad spectrum pesticides. These pesticides can cause health problems in humans, and the vectors can become resistant to these chemicals. A new strategy has emerged that involves genetically modifying mosquitoes to disrupt their ability to reproduce. This limits the mosquito population, reducing the possibility of disease spread.
Sterile Insect Technique (SIT) against Aedes Species Mosquitoes: A Roadmap and Good Practice Framework for Designing, Implementing and Evaluating Pilot Field Trials
16659C. F. Oliva, M. Q. Benedict, C. M. Collins, T. Baldet, R. Bellini, H. Bossin, J. Bouyer, V. Corbel, L. Facchinelli, F. Fouque, M. Geier, A. Michaelakis, D. Roiz, F. Simard, C. Tur and L.-C. Gouagna, Insects, 12. 2021-02-24 13:44:35.
We offer here a pragmatic and accessible ‘roadmap’ for the pre-pilot and pilot phases to guide any interested party. This will support stakeholders, non-specialist scientists, implementers, and decision-makers. Applying these concepts will ensure, given adequate resources, a sound basis for local field trialing and for developing experience with the technique in readiness for potential operational deployment. This synthesis is based on the available literature, in addition to the experience and current knowledge of the expert contributing authors in this field. We describe a typical path to successful pilot testing, with the four concurrent development streams of Laboratory, Field, Stakeholder Relations, and the Business and Compliance Case. We provide a graphic framework with criteria that must be met in order to proceed.
Mosquito trial will begin in April, but Keys locations won’t be disclosed
16483S. Matthis, KEYSWEEKLY, 2021-02-23 20:54:42.
FKMCD spokesman Chad Huff wrote in an email, “The physical location of each box is still being finalized. Since most will be situated on private property at owner request, FKMCD-Oxitec will NOT be providing specific addresses due to privacy concerns and protection of project integrity.” Phil Goodman, chairman of the FKMCD said the decision to keep addresses confidential was an operations decision, not a decision by the elected board. “Right now, we don’t have any specific sites that are 100 percent selected,” said Andrea Leal, executive director of the FKMCD. “We are just narrowing down areas with potential.”
Locals protest over genetically modified mosquito plan in Florida Keys
16479D. Goodhue, Miami Herald, 2021-02-23 14:11:23.
Sometime this year, somewhere in the Florida Keys, a British biotech company is expected to release millions of genetically modified male mosquitoes in an effort to breed out of existence an invasive species of bug responsible for the transmittal of deadly diseases like dengue fever, chikungunya and Zika. But, the pilot project remains controversial, and a large segment of people who live in the island chain are trying to stop it. About two dozen people gathered Sunday morning outside the Murray Nelson Government and Cultural Arts Center in Key Largo to protest the planned release of the lab-designed bugs.
Operational Parameters for the Aerial Release of Sterile Codling Moths Using an Uncrewed Aircraft System
17762E. D. Esch, R. M. Horner, D. C. Krompetz, N. Moses-Gonzales, M. R. Tesche and D. M. Suckling, Insects, 12:2/13/2021. 2021-02-13 14:52:13.
The codling moth is a serious pest of apples in most regions of the world where this fruit is produced. The sterile insect technique is one strategy used to control this pest and is employed as part of an area-wide integrated pest management program for the codling moth in British Columbia, Canada. Modified fixed wing aircraft are the most common method for the release of sterile insects in large area-wide pest management programs. However, aerial release with a full-size aircraft can be prohibitively expensive. We evaluated the use of small, uncrewed aircraft systems (UASs) for the release of sterile codling moths. Sterile codling moths released from greater altitudes were more broadly distributed and drifted more in strong winds, compared to those released from lower altitudes. Most of the released insects were recaptured in a 50 m wide swath under the release route. Recapture rates for aerially released insects were 40–70% higher compared to those released from the ground. UASs provide a promising alternative to ground release and conventional aircraft for the release of sterile codling moths.
Oxitec gears up for test releases
16386T. O'Hara, Keynews.com, 2021-02-10 15:10:19.
The United Kingdom-based biotech company Oxitec will soon announce the test locations and timetable for releasing its genetically modified mosquitoes in the Florida Keys.
GeneConvene Global Collaborative Webinar Series | Genetic Biocontrol 2021
16249David O'Brochta and Hector Quemada, GeneConvene Global Collaborative, 2021-02-05 21:53:11.
In the mid 20th century various ideas emerged concerning how genetics and genetic principles could be directly applied to age-old problems of managing insects that threaten food security and public health. This series of webinars will explore the current state-of-the-art of what has been termed genetic control, genetic pest management and genetic biocontrol. It will cover the use of sterility, conditional dominant lethality and Wolbachia-induced cytoplasmic incompatibility. Gene drive, another type of genetic biocontrol, will not be covered in this series; it was recently the focus of webinar series dedicated to the topic.
Improving the Phenotypic Properties of the Ceratitis capitata (Diptera: Tephritidae) Temperature-Sensitive Lethal Genetic Sexing Strain in Support of Sterile Insect Technique Applications
16226M. F. Porras, J. S. Meza, E. G. Rajotte, K. Bourtzis and C. Caceres, Journal of Economic Entomology, 113:2688-2694. 2021-01-31 16:33:01.
We present the first evidence that this slower development is due to a different gene, here namely slow development (sd), which is closely linked to the tsl gene. Taking advantage of recombination phenomena between the two loci, we report the isolation of a novel temperature sensitivity lethal strain using the wp mutation as a morphological marker, which showed faster development (wp tsl FD) during the larval stage and increased in its temperature sensitivity compared with the normal tsl strain. Moreover, the introgression of this novel wp tsl FD combined trait into the Vienna 8(D53-) GSS, resulted in a novel Vienna 8(D53-) FD GSS, where females showed differences in the thermal sensibility, larval development speed, and productivity profiles. The modification of these traits and their impact on the mass rearing of the GSS for sterile insect technique applications are discussed.
Sexual Competitiveness and Induced Egg Sterility by Aedes aegypti and Aedes albopictus Gamma-Irradiated Males: A Laboratory and Field Study in Mexico
17760J. G. Bond, S. Aguirre-Ibáñez, A. R. Osorio, C. F. Marina, Y. Gómez-Simuta, R. Tamayo-Escobar, A. Dor, P. Liedo, D. O. Carvalho and T. Williams, Insects, 12. 2021-01-29 14:44:07.
The sterile insect technique may prove useful for the suppression of mosquito vectors of medical importance in regions where arboviruses pose a serious public health threat. In the present study, we examined the effects of sterilizing irradiation doses across different ratios of fertile:irradiated males on the mating competitiveness of Ae. aegypti and Ae. albopictus under laboratory and field-cage conditions. For both species, the percentage of females inseminated and the number of eggs laid over two gonotrophic cycles varied significantly in mating treatments involving 1:1, 1:5, and 1:10 fertile:irradiated males compared to controls of entirely fertile or entirely irradiated males but was not generally affected by the irradiation dose. Egg hatching was negatively affected in females exposed to increasing proportions of irradiated males in both laboratory and field cages. Male competitiveness (Fried’s index) values varied from 0.19 to 0.58 in the laboratory and were between 0.09 and 1.0 in field cages, depending on th species. Competitiveness values were negatively affected by th eirradiation dose in both species under field-cage conditions, whereas in the laboratory, Ae. albopictus was sensitive to the dose but Ae. aegypti was not. In general, male competitiveness was similar across all mating regimes. Most importantly, induced egg sterility was positively correlated with the proportion of irradiated males present in the mating treatments, reaching a maximum of 88% under field-cage conditions for both Ae. aegypti and Ae. albopictus males treated with 50 and 40 Gy irradiation, respectively. These results indicate that sterile males produced at our facility are suitable and competitive enough for field pilot SIT projects and provide guidance to decide the optimal sterile:fertile ratios.
Drivers of mosquito mating
16110N. C. Manoukis, Science, 371:340. 2021-01-22 15:54:49.
Gene drive systems are based on the release of organisms whose genomes have been modified or engineered to spread a desired allele or trait (such as resistance to the parasites that cause malaria) through a population. Success will depend on the release of genetically modified males that will be able to mate with wild females. Beyond gene drive strategies, in mosquitoes it is understood that only males can be released as part of any genetic pest control (GPC) program (7); females feed on blood to lay eggs, and releasing insects that will feed on humans is widely unacceptable.
Clock genes and environmental cues coordinate Anopheles pheromone synthesis, swarming, and mating
16108G. Wang, J. Vega-Rodríguez, A. Diabate, J. Liu, C. Cui, C. Nignan, L. Dong, F. Li, C. O. Ouedrago, A. M. Bandaogo, P. S. Sawadogo, H. Maiga, T. L. Alves e Silva, T. V. Pascini, S. Wang and M. Jacobs-Lorena, Science, 371:411. 2021-01-22 15:35:30.
Knockdown of per and tim expression affects Anopheles gambiae s.s. and Anopheles stephensi male mating in the laboratory, and it reduces male An. coluzzii swarming and mating under semifield conditions. Light and temperature affect mosquito mating, possibly by modulating per and/or tim expression. Moreover, the desaturase gene desat1 is up-regulated and rhythmically expressed in the heads of swarming males and regulates the production of cuticular hydrocarbons, including heptacosane, which stimulates mating activity.
White pupae phenotype of tephritids is caused by parallel mutations of a MFS transporter
16691C. M. Ward, R. A. Aumann, M. A. Whitehead, K. Nikolouli, G. Leveque, G. Gouvi, E. Fung, S. J. Reiling, H. Djambazian, M. A. Hughes, S. Whiteford, C. Caceres-Barrios, T. N. M. Nguyen, A. Choo, P. Crisp, S. B. Sim, S. M. Geib, F. Marec, I. Hacker, J. Ragous, Nature Communications, 12. 2021-01-21 15:50:54.
Here, we use classical and modern genetic approaches to identify and functionally characterize causal wp(-) mutations in these distantly related fruit fly species. We find that the wp phenotype is produced by parallel mutations in a single, conserved gene. CRISPR/Cas9-mediated knockout of the wp gene leads to the rapid generation of white pupae strains in C. capitata and B. tryoni. The conserved phenotype and independent nature of wp(-) mutations suggest this technique can provide a generic approach to produce sexing strains in other major medical and agricultural insect pests. The white pupae (wp) phenotype has been used for decades to selectively remove females of tephritid species in genetic sexing, but the determining gene is unknown. Here, the authors show that wp phenotype is produced by parallel mutations in a Major Facilitator Superfamily domain containing gene across multiple species.
Manipulation of Gut Symbionts for Improving the Sterile Insect Technique: Quality Parameters of Bactrocera dorsalis (Diptera: Tephritidae) Genetic Sexing Strain Males After Feeding on Bacteria-Enriched Diets
17222Q. Zhang, P. Cai, B. Wang, X. Liu, J. Lin, R. Hua, H. Zhang, C. Yi, X. Song, Q. Ji, J. Yang and S. Chen, Journal of Economic Entomology, 114:560-570. 2021-01-18 16:16:41.
One environmentally friendly method used to manage Bactrocera dorsalis (Hendel), a key agricultural pest of substantial economic importance, is the sterile insect technique (SIT). Nevertheless, several deficiencies related to this strategy impair the success of the SIT, including the inferior performance of released sterile males compared with wild males, which could be partly solved by the utilization of gut symbionts as probiotic dietary components. In this study, a culture-dependent method was used to isolate and characterize gut-associated bacterial species in adult B. dorsalis genetic sexing strain (GSS) males. In addition, three bacterial isolates from the Enterobacteriaceae family, namely, Enterobacter sp., Morganella morganii, and Moellerella wisconsensis, were used as supplements in larval and adult diets to assess their effects on the life-history traits of irradiated males. Consistent with many previous studies, Enterobacter spp. was shown to be beneficial, with some quality control indices, such as adult size, pupal weight, survival rate under stress and nutritionally rich conditions, and mating competitiveness, being significantly increased, while slight nonsignificant increases in emergence rate and flight ability were observed. Conversely, the M. morganii and M. wisconsensis strains both had negative effects on irradiated male fitness and mating competitiveness. Our results, in combination with those of earlier studies, can contribute to improving the effectiveness of SIT application by enhancing the different aspects of augmentative rearing and biological traits of pests under laboratory rearing conditions.
Population Dynamics of Aedes aegypti and Aedes albopictus in Two Rural Villages in Southern Mexico: Baseline Data for an Evaluation of the Sterile Insect Technique
17758C. F. Marina, J. G. Bond, K. Hernández-Arriaga, J. Valle, A. Ulloa, I. Fernández-Salas, D. O. Carvalho, K. Bourtzis, A. Dor, T. Williams and P. Liedo, Insects, 12. 2021-01-11 14:36:35.
Indoor and outdoor ovitraps were placed in 15 randomly selected houses in two rural villages in Chiapas, southern Mexico. In addition, ovitraps were placed in five transects surrounding each village, with three traps per transect, one at the edge, one at 50 m, and another at 100 m from the edge of the village. All traps were inspected weekly. A transect with eight traps along a road between the two villages was also included. Population fluctuations of Aedes aegypti and Ae. albopictus were examined during 2016–2018 by counting egg numbers. A higher number of Aedes spp. eggs was recorded at Hidalgo village with 257,712 eggs (60.9%), of which 58.1% were present in outdoor ovitraps and 41.9% in indoor ovitraps, compared with 165,623 eggs (39.1%) collected in the village of Río Florido, 49.0% in outdoor and 51.0% in indoor ovitraps. A total of 84,047 eggs was collected from ovitraps placed along transects around Río Florido, compared to 67,542 eggs recorded from transects around Hidalgo. Fluctuations in egg counts were associated with annual variation in precipitation, with 2.3 to 3.2-fold more eggs collected from ovitraps placed in houses and 4.8 to 5.1-fold more eggs in ovitraps from the surrounding transects during the rainy season than in the dry season, respectively. Aedes aegypti was the dominant species during the dry season and at the start of the rainy season in both villages. Aedes albopictus populations were lower for most of the dry season, but increased during the rainy season and predominated at the end of the rainy season in both villages. Aedes albopictus was also the dominant species in the zones surrounding both villages. The numbers of eggs collected from intradomiciliary ovitraps were strongly correlated with the numbers of eggs in peridomiciliary ovitraps in both Río Florido (R2adj = 0.92) and Hidalgo (R2adj = 0.94), suggesting that peridomiciliary sampling could provide an accurate estimate of intradomiciliary oviposition by Aedes spp. in future studies in these villages. We conclude that the feasibility of sterile insect technique (SIT)-based program of vector control could be evaluated in the isolated Ae. aegypti populations in the rural villages of our baseline study.
Sterile Insect Technique: Principles and Practice in Area-Wide Integrated Pest Management (2nd ed.)
17495V. A. Dyck, J. Hendrichs and A. S. Robinson, CRC Press, 2021-01-06 15:33:05.
For several major insect pests, the environment-friendly sterile insect technique (SIT) is being applied as a component of area-wide integrated pest management (AW-IPM) programmes. This technology, using radiation to sterilize insects, was first developed in the USA, and is currently applied on six continents. For almost six decades it has been a major subject for research and development in the Joint FAO/IAEA Programme on Nuclear Techniques in Food and Agriculture, involving both research and the transfer of this technology to Member States so that they can benefit from improved plant, animal and human health, cleaner environments, increased production of plants and animals in agricultural systems, and accelerated economic development. The socio-economic impacts of AW-IPM programmes that integrate the SIT have confirmed the usefulness of this technology. Numerous publications related to the integration of the SIT in pest management programmes, arising from research, coordinated research projects, field projects, symposia, meetings, and training activities have already provided much information to researchers, pest-control practitioners, programme managers, plant protection and animal health officers, and policy makers. However, by bringing together and presenting in a generic fashion the principles, practice, and global application of the SIT, this book serves as a major reference source for all current and future users of the technology, and also serves as a textbook for academic courses on integrated pest management.
ARS Science Key to Stopping ‘Man-Eating’ Parasite
15973S. Elliott, Tellus, 2021-01-04 19:30:15.
Screwworm infestations were once prevalent in the United States, with 230,000 cases reported in 1935 alone. ARS scientists Edward Knipling and Raymond Bushland conceived and developed the sterile insect technique (SIT) to control and eradicate screwworms. With SIT, sterilized male blow flies were released to breed with wild flies. Since female blow flies mate only once, the coupling effectively removed that female and her potential offspring from the population.
Transgenic cotton and sterile insect releases synergize eradication of pink bollworm a century after it invaded the United States
15697B. E. Tabashnik, L. R. Liesner, P. C. Ellsworth, G. C. Unnithan, J. A. Fabrick, S. E. Naranjo, X. Li, T. J. Dennehy, L. Antilla, R. T. Staten and Y. Carrière, Proceedings of the National Academy of Sciences, 118:e2019115118. 2020-12-28 18:26:42.
The program included releases of billions of sterile pink bollworm moths from airplanes and planting of cotton engineered to produce insect-killing proteins from the bacterium Bacillus thuringiensis. Analysis of computer simulations and 21 y of field data from Arizona indicate these two tactics interacted synergistically to suppress the pest. By eradicating the pink bollworm, the program ended the damage it caused to cotton and the insecticide sprays used to control it, yielding economic, environmental, and social benefits.Invasive organisms pose a global threat and are exceptionally difficult to eradicate after they become abundant in their new habitats.
Genetic pest management and the background genetics of release strains
15695P. T. Leftwich, L. G. Spurgin, T. Harvey-Samuel, C. J. E. Thomas, L. C. Paladino, M. P. Edgington and L. Alphey, Philosophical Transactions of the Royal Society B: Biological Sciences, 376:20190805. 2020-12-28 15:35:20.
We discuss issues around strain selection and the potential consequences of such introgression. We conclude that such introgression is probably harmless in almost all circumstances, and could, in theory, provide specific additional benefits to the release programme. We outline population monitoring approaches that could be used, going forward, to determine how background genetics may affect GPM. This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases’.
Genetic sexing strains for the population suppression of the mosquito vector Aedes aegypti
15691P. Koskinioti, A. A. Augustinos, D. O. Carvalho, M. Misbah-ul-Haq, G. Pillwax, L. D. d. l. Fuente, G. Salvador-Herranz, R. A. Herrero and K. Bourtzis, Philosophical Transactions of the Royal Society B: Biological Sciences, 376:20190808. 2020-12-28 15:27:53.
Here, we report on the construction of two genetic sexing strains using red- and white-eye colour mutations as selectable markers. Quality control analysis showed that the Red-eye genetic sexing strains (GSS) is better and more genetically stable than the White-eye GSS. The introduction of an irradiation-induced inversion (Inv35) increases genetic stability and reduces the probability of female contamination of the male release batches. Bi-weekly releases of irradiated males of both the Red-eye GSS and the Red-eye GSS/Inv35 fully suppressed target laboratory cage populations within six and nine weeks, respectively
CRISPR/Cas9 knockout of female-biased genes AeAct-4 or myo-fem in Ae. aegypti results in a flightless phenotype in female, but not male mosquitoes
15617S. O’Leary and Z. N. Adelman, PLOS Neglected Tropical Diseases, 14:e0008971. 2020-12-18 16:05:35.
Author summary Ae. aegypti is the most important vector of arboviruses throughout the world, and new strategies are urgently needed to add to our existing arsenal of control methods to prevent or halt disease transmission. Importantly, only female Ae. aegypti mosquitoes transmit arboviruses due to their need for vertebrate blood to support egg production. Here, we identify several genes that are critical only for female mosquito flight; genetic ablation of each gene resulted in flightless females, but flying males. Importantly, the female flightless phenotype was completely penetrant (100%), and the use of sex-biased flight muscle proteins appeared to be conserved throughout mosquito evolution. These data could be used to support the development of novel genetic control approaches to reduce the number of biting females across a wide range of disease vector species.
Precise single base substitution in the shibire gene by CRISPR/Cas9-mediated homology directed repair in Bactrocera tryoni
16693A. Choo, E. Fung, I. Y. Chen, R. Saint, P. Crisp and S. W. Baxter, BMC Genetics, 21. 2020-12-18 15:58:10.
Here we introduce a known Drosophila melanogaster temperature sensitive embryonic lethal mutation into Bactrocera tryoni, a serious horticultural pest in Australia. A non-synonymous point mutation in the D. melanogaster gene shibire causes embryonic lethality at 29 degrees C and we successfully used CRISPR/Cas9 technology to recreate the orthologous shibire temperature sensitive-1 (shi(ts1)) mutation in B. tryoni. Genotypic analyses over three generations revealed that a high fitness cost was associated with the shi(ts1) mutant allele and shi(ts1) homozygotes were not viable at 21 degrees C, which is a more severe phenotype than that documented in D. melanogaster.ConclusionsWe have demonstrated the first successful use of CRISPR/Cas9 to introduce precise single base substitutions in an endogenous gene via homology-directed repair in an agricultural pest insect and this technology can be used to trial other conditional mutations for the ultimate aim of generating genetic sexing strains for SIT.
Converting female mosquitoes to non-biting males with implications for mosquito control
15614M. V. Candy, Vet Candy, 2020-12-18 15:57:05.
Virginia Tech researchers have proven that a single gene can convert female Aedes aegypti mosquitoes into fertile male mosquitoes and identified a gene needed for male mosquito flight. Male mosquitoes do not bite and are unable to transmit pathogens to humans. Female mosquitoes, on the other hand, are able to bite. Female Aedes aegypti mosquitoes require blood to produce eggs, making them the prime carriers of the pathogens that cause Zika and dengue fever in humans. "The presence of a male-determining locus (M locus) establishes the male sex in Aedes aegypti and the M locus is only inherited by the male offspring, much like the human Y chromosome," said Zhijian Tu, a professor in the Department of Biochemistry in the College of Agriculture and Life Sciences. "By inserting Nix, a previously discovered male-determining gene in the M locus of Aedes aegypti, into a chromosomal region that can be inherited by females, we showed that Nix alone was sufficient to convert females to fertile males. This may have implications for developing future mosquito control techniques." These findings were published in the Proceedings of the National Academy of Sciences.
FKMCD – Oxitec | Mosquito Project Webinar Series
15564Oxitec Ltd, FKMCD and Oxitec, 2020-12-18 15:43:23.
This FKMCD - Oxitec Public Educational Webinar, our ninth, shows how Oxitec's just-add-water technology helps control the Aedes aegypti mosquito population. The second half of the webinar includes questions and answers with attendees.
Fear of Oxitec mosquito release grows
15541T. Java, Florida Keys Free Press, 2020-12-16 20:11:11.
A local effort has emerged to exclude Key Largo from a test release of genetically modified Aedes aegypti mosquitoes planned for the spring. The U.S. Environmental Protection Agency and the Florida Keys Mosquito Control District have approved a release of United Kingdom-based biotech company Oxitec’s GMO insects in an effort to battle the disease-carrying wild mosquito population by effectively breeding it out of existence.
A patent review on strategies for biological control of mosquito vector
15377K. Parihar, M. Telang and A. Ovhal, World Journal of Microbiology and Biotechnology, 36:23. 2020-12-09 20:28:33.
This paper presents a comprehensive technology overview of patent documents disclosing biological agents for mosquito control. The patent analysis revealed that comparable number of patent documents were filed in two technology categories: non-recombinant agents and genetically modified (GM) agents. In the category of non-recombinant agents, toxic peptides from microbes and biological consortia seemed to be the earliest technology noted right from the year 1965 whereas the patent filings for suppression of mosquito population using genetic modification techniques have emerged from the year 2000 onwards. The United States of America is the leading patent filing jurisdiction followed by China and the Great Britain. Academic institutes have filed higher number of patent applications as compared to private companies. University of Florida was found to be the leading patent filing entity and its patents were focused on suppression of vector population using techniques such as release of insects with dominant lethal (RIDL) and RNA interference (RNAi).
Modelling the Wolbachia incompatible insect technique: strategies for effective mosquito population elimination
15281D. E. Pagendam, B. J. Trewin, N. Snoad, S. A. Ritchie, A. A. Hoffmann, K. M. Staunton, C. Paton and N. Beebe, BMC Biology, 18:13. 2020-12-02 16:29:23.
We introduce a simple Markov population process model for studying mosquito populations subjected to a Wolbachia-IIT programme which exhibit an unstable equilibrium threshold. The model is used to study, in silico, scenarios that are likely to yield a successful elimination result. Our results suggest that elimination is best achieved by releasing males at rates that adapt to the ever-decreasing wild population, thus reducing the risk of releasing Wolbachia-infected females while reducing costs.
Strategic Approach, Advances, and Challenges in the Development and Application of the SIT for Area-Wide Control of Aedes albopictus Mosquitoes in Reunion Island
15267L. C. Gouagna, D. Damiens, C. F. Oliva, S. Boyer, G. Le Goff, C. Brengues, J.-S. Dehecq, J. Raude, F. Simard and D. Fontenille, Insects, 11:770. 2020-11-30 19:17:02.
Combined Effects of Mating Disruption, Insecticides, and the Sterile Insect Technique on Cydia pomonella in New Zealand
15958R. M. Horner, P. L. Lo, D. J. Rogers, J. T. S. Walker and D. M. Suckling, Insects, 11:23. 2020-11-27 18:11:55.
We aimed to supplement these tactics with the sterile insect technique (SIT) to further suppress the codling moth on orchards. SIT involves mass rearing and sterilizing codling moth and then releasing them onto orchards where they mate with wild insects resulting in no offspring. We released sterile insects onto seven orchards using unmanned aerial vehicles and ground releases. Six years of the program saw significant drops (90-99%) in wild moth populations. The SIT is an excellent tactic for reducing moth populations in export apple orchards.
Field Competitiveness of Aedes albopictus (Diptera: Culicidae) Irradiated Males in Pilot Sterile Insect Technique Trials in Northern Italy
16988R. Bellini, M. Carrieri, F. Balestrino, A. Puggioli, M. Malfacini and J. Bouyer, Journal of Medical Entomology, 58:807-813. 2020-11-20 14:50:15.
Vector-borne diseases account for 17% of infectious diseases, leading to more than one million deaths each year. Mosquitoes are responsible for 90% of the casualties and alternative control methods to insecticides are urgently needed, especially against Aedes vectors. Aedes albopictus is a particularly important species, causing major public health problems because it is a vector of several arboviruses and has a strong invasive behavior. Various genetic control methods have been proposed to be integrated into the management strategies of Aedes species, among which the sterile insect technique (SIT), which proved efficient against various insect pests and vectors. However, the ability of released irradiated sterile male mosquitoes to compete with their wild counterparts and induce sterility in wild females, which is critical to the success of this strategy, remained poorly defined. Here, we assessed the field competitiveness of Ae. albopictus irradiated male using data from eight release trials implemented in Northern Italy for 3 yr. Sterile males were capable of inducing a good level of sterility in the wild female population, however, with high variability in time and space. The field competitiveness of the released males was strongly negatively correlated with the ratio of sterile to wild males.This should be taken into consideration when designing future programs to suppress field populations of Aedes mosquitoes.
‘A plague to be reckoned with’: UMN research creates a buzz with invasive fruit fly research
15238B. Most, The Minnesota Daily, 2020-11-18 13:26:31.
n early November, assistant professor Mike Smanski published an article about a new breakthrough in this research, demonstrating for the first time this kind of genetic engineering was possible in the common fruit fly. This shows that researchers could engineer this work into spotted wing drosophila in the future. The University’s Smanski Lab has also studied this technique in mosquitoes, zebra fish and carp, but never with this type of fruit fly, he said. “These are all a new class of genetic pesticide, basically, that allow you to engineer the pest organism itself and convert that pest organism into the pesticide,” Smanski said. Through this work the researchers can create a pest that is biologically the same, but when the females mate with these genetically modified males, they will not produce viable offspring, he said. This sterile insect technique can be helpful not only in reducing the population of insects, but in reducing the impacts of insecticides on surrounding species and nearby ecosystems, said Feltman, a second-year biochemistry, molecular biology and biophysics graduate student.
Assessment of a Novel Adult Mass-Rearing Cage for Aedes albopictus (Skuse) and Anopheles arabiensis (Patton).
15562H. Maïga, W. Mamai, N. S. Bimbilé Somda, T. Wallner, B. S. Poda, G. Salvador-Herranz, R. Argiles-Herrero, H. Yamada and J. Bouyer, Insects, 11:801. 2020-11-13 15:09:03.
Successful implementation of the sterile insect technique (SIT) against Aedes albopictus and Anopheles arabiensis relies on a continuous supply of sterile males. To meet this requirement, optimization of the mass-rearing techniques is needed. This study, therefore, aims to assess a new mass-rearing cage (MRC) in terms of egg production efficiency and egg hatch rate (quality). In addition, adult survival was evaluated based on a cage adult-index for Ae. albopictus. Moreover, the cage’s suitability for use in mass An. arabiensis egg production was compared to that of the FAO/IAEA Anopheles reference cage. In Ae. albopictus rearing, the new MRC produced 1,112,110 eggs per cage following six blood meals, with minimum loss of eggs in the egging water. Furthermore, the adult index gave a good proxy of daily mortality rates in Ae. albopictus. In An. arabiensis rearing, about 130,000 eggs per egg batch were collected both from the new and the reference MRC. These findings suggest that the new MRC prototype is efficient in terms of egg production and can be used for mass-rearing in SIT programs targeting Ae. albopictus as well as An. arabiensis. The adult index was also positively validated for the detection of unusual mortality rates in Ae. albopictus mass-rearing facilities. Overall, the new MRC has shown several advantages; however, further improvements are necessary to minimize escapes during the egg collection processes
Fighting Mosquito With GMO Mosquito: The Battle Brewing in the Florida Keys
15005S. MacLaughlin, NBC 6 South Florida, 2020-11-06 15:32:04.
Scientists are a few months into an experiment to stop the invasive Aedes aegypti mosquito. Their weapon of choice? A genetically modified mosquito. But some environment advocates question the strategy. This year, the Florida Keys had an outbreak of Dengue fever, which was the first time that had happened in 10 years. It gives new urgency to the controversial effort to get rid of the Aedes aegypti, which has become harder to fight.
Florida will release 750 million genetically modified mosquitoes
14998S. McGlaun, Slash Gear, 2020-11-05 15:14:43.
Local officials in Florida have announced that they have approved 750 million genetically modified mosquitoes to be released into the environment to reduce local populations of the bloodsucking creatures. The goal of releasing genetically modified mosquitoes is to help reduce the number of mosquitoes carrying diseases like dengue or the Zika virus. Approval to release the bugs came after environmental groups warned of unintended consequences.
Genetic engineering of sex chromosomes for batch cultivation of non-transgenic, sex-sorted males
19246S. R. Das, M. Maselko, A. Upadhyay and M. J. Smanski, PloS Genetics, 16:11. 2020-11-02 22:13:55.
The field performance of Sterile Insect Technique (SIT) is improved by sex-sorting and releasing only sterile males. This can be accomplished by resource-intensive separation of males from females by morphology. Alternatively, sex-ratio biasing genetic constructs can be used to selectively remove one sex without the need for manual or automated sorting, but the resulting genetically engineered (GE) control agents would be subject to additional governmental regulation. Here we describe and demonstrate a genetic method for the batch production of non-GE males. This method could be applied to generate the heterogametic sex (XY, or WZ) in any organism with chromosomal sex determination. We observed up to 100% sex-selection with batch cultures of more than 10(3) individuals. Using a stringent transgene detection assay, we demonstrate the potential of mass production of transgene free males. Author summary In this manuscript, we describe and demonstrate in a model system a new genetic engineering approach for producing sex-sorted, non-transgenic batches of an organism with genetic sex determination. This approach could impact pest control programs using Sterile Insect Technique.
The Sterile Insect Technique: Success and Perspectives in the Neotropics
15185D. Perez-Staples, F. Diaz-Fleischer and P. Montoya, Neotropical Entomology, 14. 2020-10-28 15:12:56.
Here, we review SIT in the Neotropics and focus on particular recent successful cases of eradication of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), as well as effective programs used against the Mexican fruit fly Anastrepha ludens (Loew), the New World screwworm fly Cochliomyia hominivorax (Coquerel)), and the Cactus moth Cactoblastis cactorum (Berg). We examine when SIT does not work and innovations that have made SIT more efficient and also highlight complimentary techniques that can be used in conjunction. We address potential candidate species that could be controlled through SIT, for example Philornis downsi Dodge & Aitken. Finally, we consider the impact of climate change in the context of the use of the SIT against these pests. Given the recent dramatic decline in insect biodiversity, investing in environmentally friendly means of pest control should be a priority. We conclude that SIT should be promoted in the region, and leadership and political will is needed for continued success of SIT in the Neotropics.
Educating the Public on Genetically Modified Mosquitoes
18527Buckner, Eva A., UF - IFAS, 2020-10-26 16:04:58.
In May 2020, the U.S. Environmental Protection Agency (EPA) approved Oxitec’s Experimental Use Permit to carry out pilot projects in the Florida Keys. Oxitec is a biotechnology company founded in 2002 out of Oxford University in the United Kingdom. They will be collaborating with the Florida Keys Mosquito Control District. One of the pilot projects will involve releasing Oxitec’s GM Ae. aegypti male mosquitoes (strain OX5034) into a small area to test their ability to reduce the population of wild Ae. aegypti mosquitoes. This project will be the first time that GM mosquitoes are released into nature in the U.S. and is expected to begin in early spring 2021 and continue through spring 2022. The purpose of this document is to provide essential information about GM mosquitoes to the public and those involved in mosquito control in Florida, the U.S., and beyond. Below we present a series of answers to frequently asked questions about the nature of GM mosquitoes, the argument for using GM mosquitoes to control mosquito-transmitted diseases, and the potential impact of this project on the environment and human health. Our hope is that these answers will provide readers with insight into the reasons why GM mosquitoes are being tested for mosquito control in Florida and elsewhere.
FKMCD-OXITEC Mosquito Project
14718FKMCD and OXITEC, Website, 2020-10-16 18:11:37.
The Florida Keys Mosquito Control District (FKMCD) Board of Commissioners approved the FKMCD-Oxitec Investigational Agreement for the release of Oxitec’s Aedes aegypti mosquitoes. This project will be overseen by FKMCD, the EPA and the Florida Department of Agriculture and Consumer Services (FDACS). Independent evaluation of the project will be provided by the U.S. CDC, University of Florida, Monroe County Department of Health, and local leaders, forming a broad and diverse coalition to support this effort.
Florida to Release 750 Million GMO Mosquitoes in 2021
14703Seeker, Seeker, 2020-10-13 18:11:21.
The U.S. EPA gave the green light to release millions of genetically modified mosquitoes in the Florida Keys in 2021 — here’s what we know.
Yes, Irradiated Sterile Male Mosquitoes Can Be Sexually Competitive!
14645J. Bouyer and M. J. B. Vreysen, Trends in Parasitology, 2020-10-06 13:28:30.
Here, we argue that a reduction in quality of the produced sterile male insects is mostly related to the mass-rearing, handling, marking, and release processes, rather than radiation per se.
You should be excited that scientists are releasing 750 million genetically modified mosquitoes this year
14568L. Westreich, Massive Science, 2020-09-27 19:27:28.
GM mosquitoes are successful in reducing mosquito populations, and reducing disease spread
The Con Job at Mosquito Control Board
14571E. Russo and B. Wray, keysnews.com, 2020-09-26 19:32:07.
Shouldn’t there be a consensus among scholars, scientists, experts and the public that this new technology is safe?
Gene Drive: Modern Miracle or Environmental Disaster
14491K. Brooks, Journal of Law, Technology and Policy, 2020-09-25 19:57:31.
This Note will show how gene drive technology fits imperfectly into the old regulatory framework through case studies. The Analysis will also describe how the different regulatory agencies handle similar gene drive-like organisms inconsistently, and the inherent danger of this approach considering upcoming developments in the field.
Can a Genetically Modified Bug Combat a Global Farm Plague?
14470E. Nitler, Wired, 2020-09-24 17:24:48.
Executives from the US-owned, but UK-based, firm Oxitec and its multinational partner Bayer announced today that they have developed a fall armyworm that has a self-limiting gene introduced into the male of the species.
Dynamics of Wild and Sterile Mosquito Population Models with Delayed Releasing
14817L. M. Cai, International Journal of Bifurcation and Chaos, 30:15. 2020-09-15 17:16:03.
We extend the previous ODE models to the delayed releasing models in two different ways of releasing sterile mosquitos, where both constant and exponentially distributed delays are considered, respectively. By applying the theory and methods of delay differential equations, the effect of time delays on the stability of equilibria in the system is rigorously analyzed.
How to fight the deadly dengue virus? Make your own mosquitoes
14320J. Emont, Wall Street Journal, 2020-09-07 15:13:25.
When the bacteria-laden male mosquitoes are released into the open and mate with naturally-born females, the resultant eggs won’t hatch.
GMOs make war on mosquitoes
14323Staff, Kenosha News, 2020-09-05 15:13:38.
Given that recent record, we were a bit surprised to read that there was a ruckus over genetically modified mosquitoes going on in the Florida Keys.
Why Genetically Modified Mosquitoes Won’t Come to Texas Anytime Soon
14317C. Adams, RA News, 2020-09-04 15:03:04.
Talks about releasing genetically modified mosquitoes in Houston began in 2018 between Harris County and Oxitec, a United Kingdom-based company that produces sustainable technologies or transgenic methodologies to stem the impact of disease-spreading insects. Talk also began about a similar action in Monroe County, Fla.
Do Africans need genetically modified mosquitoes?
14261genetically modified, mosquito, oxitec, autocidal, SIT, perspective, malaria, gene drive synthetic, engagement,, Mail and Guardian, 2020-09-01 14:32:06.
The following is an updated version of an article I wrote for the University of Michigan Risk Science Centre a while ago:
An accident waiting to happen: Tech company to release 750 MILLION GMO mosquitoes in Florida to fight dengue fever
14232Z. Sky, NEWSTARGET, 2020-08-30 20:31:13.
Oxitec plans to release 750 million OX5034s into the Florida Keys, something that sounds like the beginning of a doomed science-fiction movie. But the most shocking thing here is the fact that Oxitec received the EPA’s approval in May.
Genetically-modified mosquito plan offers hope for Keys, world
14256P. Goodman, keynews.com, 2020-08-29 14:25:12.
The Florida Keys Mosquito Control District Board of Commissioners voted 4-to-1 to approve a trial using Oxitec’s second-generation genetically modified mosquitoes. I
The good mosquito versus the bad
14240D. Datta, Business Standard, 2020-08-29 14:01:00.
Starting 2021, around 750 million genetically modified (GM) Aedes Aegypti mosquitoes will be released in batches into the Florida Keys.
Florida Will Release 750 Genetically Modified Mosquitoes to Stop Disease Spread
14177A. Fahmy, verywell health, 2020-08-28 14:36:32.
The hope is to prevent the spread of Dengue fever, a painful virus acquired only by mosquito bite which made a reappearance in the Florida Keys in 2009.
Deep dive: Florida’s GM mosquito experiment aims to rewrite rules of vector-borne diseases
14084S. Kannan, India Today, 2020-08-26 14:33:36.
A pathbreaking bioengineering experiment on mosquito populations that could have massive implications for tropical malaria-affected countries like India has got underway in Florida, US.
Fighting mosquito-borne diseases… with mosquitoes
14156N. Gubert and A. Baubeau, Phys Org, 2020-08-26 13:13:41.
For decades, researchers have scratched their heads over how to combat deadly mosquito-borne diseases such as dengue fever.
Bug board OKs release of genetically modified mosquitoes
14151T. O'Hara, keynews.com, 2020-08-26 13:08:07.
After nearly 10 years of debate, the Florida Keys Mosquito Control District board has approved an agreement with biotech company Oxitec to conduct a test release of genetically modified mosquitoes in Monroe County as part of a mosquito limiting or eradication plan.
Genetically modified mosquitoes to be released in the Florida Keys to combat dengue, zika, and yellow fever.
14148Yucatan Times, Yucatan Times, 2020-08-26 13:04:27.
The Florida Keys will be the scene of the first test in the United States with genetically modified Aedes aegypti mosquitoes, an alternative to insecticides and larvicides to end the transmission of diseases such as dengue, zika and yellow fever that has always been surrounded by controversy.
Transgenic moths released to end one of the worst pests on the planet
14099B. Mandalia, Pledge Times, 2020-08-25 14:49:50.
Today the results of the first open field experiment with another of the creations of this biotechnology company are published. It is a variant of the moth Plutella xylostella which is one of the worst agricultural pests in the world.
750 million genetically modified mosquitoes soon released in the wild!
14093explica, explica, 2020-08-25 14:42:52.
Rather frightening mosquitoes will be released on an archipelago in Florida. The goal? Reduce the population of their more dangerous congeners who can transmit certain diseases.
US to Use Genetically Modified Mosquitoes to Fight Dengue Fever
14090H. Badr, Asharq Al-Awsat, 2020-08-25 14:39:32.
After a decade of discussions, officials in Florida have voted to allow the first test in the United States of free-flying, genetically modified mosquitoes that kill any female offspring, as a way to fight the pests and the diseases they spread.
Florida Keys to Use Genetically Modified Mosquitoes to Fight Disease
14087B. Lynn, Voice of America, 2020-08-25 14:33:57.
Officials in the Florida Keys plan to release genetically modified mosquitoes next year in an effort to fight insect-borne diseases.
Florida Approves Controversial Plan to Release 750 Million Genetically Modified Mosquitoes
14096D. Rakshit, Swaddle, 2020-08-24 14:46:17.
Authorities in Florida have approved a pilot project that will release 750 million genetically modified mosquitoes locally, in a bid to reduce the populations of mosquitoes that cause that cause dengue, Zika, chikungunya, and yellow fever
Mutant bugs released to fight disease
14081The Day, The Day, 2020-08-24 14:20:37.
Authorities have approved the scheme in Florida but environmental groups are furious, calling it a “Jurassic Park experiment” that will unleash a “mutant bug” into the ecosystem.
More than 750 million GMO mosquitoes to be released over Florida Keys – what could go wrong?
14145E. Huff, Natural News, 2020-08-24 12:59:20.
The Florida Keys Mosquito Control District (FKMCD) has given Oxitec, a corporation we have reported on in the past, permission to unleash some 750 million GMO mosquitos in Monroe County, Florida, over the next two years.
Florida to release genetically modified mosquitoes to prevent diseases like Zika
14009The West News, The West News, 2020-08-23 17:50:16.
Local authorities on Tuesday gave final approval to release 750 million genetically modified mosquitoes in the Florida Keys over a two-year period, starting in 2021.
Genetically modified mosquitoes have been OK’d for a first U.S. test flight
14003S. Milius, ScienceNews, 2020-08-22 17:44:31.
After a decade of fits and starts, officials in the Florida Keys have voted to allow the first test in the United States of free-flying, genetically modified mosquitoes as a way to fight the pests and the diseases they spread.
Florida Will Release Genetically Modified Mosquitoes to Fight Disease in the Keys
14000S. Harrell, Spectrum News, 2020-08-21 17:40:14.
Following lengthy federal and state procedures, the Florida Keys Mosquito Control District this week approved a plan to release more than 750 million genetically modified mosquitoes in the Keys region to combat an invasive, disease-carrying species of the insect.
Florida is releasing 750 million genetically modified mosquitoes into the world. Here’s why
13992H. Schriber, Deseret News, 2020-08-21 17:35:50.
Florida officials plan to release 750 million genetically modified mosquitoes into the Florida Keys over the next two years as a way to prevent diseases like the Zika virus. The project will begin in 2021. The Environment Protection Agency approved the idea in May. The project will test if one of these mosquitoes can work better than spraying insecticides to stop these insects from spreading potentially fatal viruses, according to CNN.
Genetically Modified Mosquitoes To Be Released In Florida Keys
13989A. Snow, The Daily Wire, 2020-08-21 17:33:00.
CNN reported that the genetically modified bugs, called OX5034, have been “altered to produce female offspring that die in the larval stage, well before hatching and growing large enough to bite and spread disease.” Since it’s the female of the species that bite, they are the ones that carry diseases. Males, the outlet reported, eat nectar.
Release 750 Million Genetically Modified Mosquitoes Into the Wild, They Said
13986C. Delbert, Popular Mechanics, 2020-08-21 17:31:14.
Corporate scientists have received final approval from the Environmental Protection Agency (EPA) to release hundreds of millions of genetically altered mosquitoes into the Florida Keys. The goal? To begin reining in the mosquito population, which is only expected to increase as climate change continues to warm and flood the low-lying, tropical Keys. But some environmental groups object strongly to the move.
Florida releasing genetically modified mosquitoes to prevent diseases like Zika
13984N. Lanese, LiveScience, 2020-08-21 17:29:18.
Hundreds of millions of genetically modified mosquitoes will soon be released in the Florida Keys island chain to wipe out local populations of disease-carrying mosquitoes, according to news reports.
750 Million GM Mosquitoes Will Be Released in the Florida Keys
13982L. Winter, The Scientist, 2020-08-21 17:27:30.
With the aim of reducing rates of the mosquito-borne illnesses yellow fever and dengue, a pilot program will release 750 million genetically modified mosquitoes into the Florida Keys in 2021, thanks to approval by the barrier islands’ Mosquito Control District Board of Commissioners at a meeting on Tuesday (August 18)
Hundreds Of Millions Of Genetically Modified Mosquitoes Approved For Release In US
13996J. Vibes, Anonymous News, 2020-08-20 17:37:24.
A Biotech company called Oxitec has received permission from the government to release hundreds of millions of genetically modified male mosquitoes in the Florida Keys.
Why Hundreds of Millions of Genetically Engineered Mosquitoes Will Soon Be Released in Florida
13979K. Gander, Newsweek, 2020-08-20 17:22:07.
Hundreds of millions of genetically engineered mosquitoes will soon be released in Florida, in a first for the U.S. On Tuesday, the Florida Keys Mosquito Control District (FKMCD) approved plans to release the insects, who do not bite, as part of a pilot project launching next yea
Florida to release genetically modified mosquitoes, detractors blast ‘Jurassic Park’ experiment
13969D. Aaro, Fox News, 2020-08-20 15:49:28.
Local authorities on Tuesday gave final approval to release 750 million genetically modified mosquitoes in the Florida Keys over a two-year period, starting in 2021, with the hope of preventing diseases such as the Zika virus but has faced blowback and comparisons to a Steven Spielberg thriller.
750 million genetically modified mosquitoes to be released across Florida Keys
13966A. Zahid, Sky News, 2020-08-20 15:47:05.
Authorities have approved plans for genetically modified mosquitoes to be released across the Florida Keys from next year. British-based firm Oxitec has designed the project to test whether the altered mosquitoes are a viable alternative to pesticides to control and prevent the spread of diseases, including Zika and dengue.
750 million GM mosquitos set for release in Florida Keys.
13961Editorial Staff, E&T, 2020-08-20 15:43:13.
Local authorities have approved proposals to release hundreds of millions of genetically modified (GM) modified mosquitos in Florida, in an effort to control populations of diseases spread by the organism.
Florida Plans to Fix Its Mosquito Problem With 750 Million More Mosquitoes
13959D. Noor, Gizmodo, 2020-08-20 15:40:34.
Hundreds of millions of mosquitos will soon be released in Florida. On purpose. The mosquitoes are being released as a form of pest control, but they could wreak havoc on local ecosystems.
Florida mosquitoes: 750 million genetically modified insects to be released
13955BBC, BBC, 2020-08-20 15:37:01.
Local officials in Florida have approved the release of 750 million mosquitoes that have been genetically modified to reduce local populations. The aim is to reduce the number of mosquitoes that carry diseases like dengue or the Zika virus.
Florida OKs release of genetically modified mosquitoes in Keys to slow insect disease spread
13952S. Mann, Just the News, 2020-08-20 15:34:23.
Florida officials are authorizing a biotech company to release hundreds of millions of genetically-modified male mosquitoes into the Florida Keys to reduce future mosquito populations that spread diseases including yellow fever and malaria.
Florida Keys to release modified mosqutioes to fight illness
13949C. Anderson, Associated Press, 2020-08-20 15:30:15.
Sometime next year, genetically modified mosquitoes will be released in the Florida Keys in an effort to combat persistent insect-borne diseases such as Dengue fever and the Zika virus. The plan approved this week by the Florida Keys Mosquito Control District calls for a pilot project in 2021 involving the striped-legged Aedes aegypti mosquito, which is not native to Florida.
Florida to Release Millions of Genetically Modified Mosquitoes Against Local Residents’ Wishes
13946N. Rice, People, 2020-08-20 15:27:38.
A plan to release over 750 million genetically modified mosquitoes in the Florida Keys has received final approval. According to CNN, on Tuesday, local authorities approved a plan to release the genetically modified mosquitoes in the Sunshine State's string of islands, with the hope of preventing a string of diseases that the insects can carry.
Plan to Release 750M GMO Mosquitoes Gets Go Ahead
13944R. Quinn, newser, 2020-08-20 15:23:41.
The plan to release the genetically modified Aedes aegypti mosquitoes received final approval from local authorities Tuesday, causing an outcry from groups opposed to what they call a "Jurassic Park experiment," CNN reports.
‘A Jurassic Park Experiment’: Watchdog Groups Denounce Decision to Release Genetically Modified Mosquitoes in Florida
13975L. Newcomb, Common Dreams, 2020-08-19 15:54:09.
Food safety and environmental groups Wednesday condemned a decision by officials in Florida to approve the release of 750 million genetically modified mosquitoes, a pilot project aimed at reducing the spread of mosquito-borne diseases.
Florida Keys to release 750M genetically modified mosquitoes
13972D. Haynes, UPI, 2020-08-19 15:51:58.
Local authorities in the Florida Keys gave their approval Wednesday to a plan to release genetically modified mosquitoes to prevent the spread of dengue fever and other diseases. The Monroe County Mosquito Control District signed off on the project, which would release about 750 million mosquitoes engineered to produce dead offspring.
FKMCD Board Approves Oxitec Pilot
14929C. Huff, FKMCD in the News, 2020-08-19 15:48:10.
The Florida Keys Mosquito Control District’s (FKMCD) five member board has APPROVED a proposal by Oxitec to utilize non-biting male, genetically modified mosquitoes as part of a trial to determine their effectiveness in controlling the wild population of Aedes aegypti, the mosquito which is responsible for spreading diseases such as dengue fever. FKMCD and Oxitec have both said that the pilot project will not take place until 2021. The FKMCD board’s four to one vote in FAVOR comes after Federal and State approvals of an ‘Experimental Use Permit’ issued earlier this summer by the Environmental Protection Agency and The Florida Department of Agriculture and Consumer Services. F
To combat disease-spreading mosquitoes in the Keys, leaders vote to unleash lab bugs
13964D. Goodhue, Miami Herald, 2020-08-19 15:44:52.
Florida Keys officials have voted to allow the experimental release of millions of genetically modified mosquitoes into a yet-to-be-decided area of the island chain.
Genetically Modified Mosquitoes Cleared for Florida Keys Release
13901J. Kay, Bloomber Law, 2020-08-18 13:36:35.
Genetically engineered mosquitoes will be released in the Florida Keys in 2021 to try to reduce the population of a biting insect pest that spreads Zika, dengue fever, and yellow fever, local officials said Tuesday.
Keys Mosquito Control Board Approves First U.S. Trial Of Genetically Modified Mosquitoes
13887N. Klingener, WLRN, 2020-08-18 13:16:55.
The Florida Keys Mosquito Control Board approved a trial Tuesday of genetically modified mosquitoes on the island chain. This would be the first U.S. trial of the genetically modified Aedes aegypti mosquito, which can transmit diseases like Zika and dengue.
Study Could Lead to Power Over Parasite
13633D. Shore, 2020-08-06 14:13:11.
Scientists have long had a name for a gruesome insect that feeds on live flesh of warm-blooded mammals: C. hominivorax, Latin for “man eater.” But now, they have the parasite’s number. In a paper published this week in the journal Communications Biology, researchers from across the United States and beyond describe the assembly and analysis of the New World screwworm’s genome — a map of the fly’s 534 million DNA base pairs.
Maintenance management and eradication of established aquatic invaders
13936D. Simberloff, Hydrobiologia, 22. 2020-08-06 13:34:15.
The rapid development of technologies based on genetics has engendered excitement about possibly eradicating or controlling terrestrial invaders, and such technologies may also prove useful for certain aquatic invaders. Methods of particular interest, alone or in various combinations, are gene-silencing, RNA-guided gene drives, and the use of transgenes.
Genomic analyses of a livestock pest, the New World screwworm, find potential targets for genetic control programs
13618M. J. Scott, J. B. Benoit, R. J. Davis, S. T. Bailey, V. Varga, E. O. Martinson, P. V. Hickner, Z. Syed, G. A. Cardoso, T. T. Torres, M. T. Weirauch, E. H. Scholl, A. M. Phillippy, A. Sagel, M. Vasquez, G. Quintero and S. R. Skoda, Nature Communications, 3:424. 2020-08-04 12:56:38.
We identify and analyze the expression of genes that are likely important for host-seeking behavior (chemosensory), development of larvae in open wounds in warm-blooded animals (heat shock protein, immune response) and for building transgenic strains for genetic control programs including gene drive (sex determination, germline). This study will underpin future experiments aimed at understanding the parasitic lifestyle of the screwworm fly and greatly facilitate future development of strains for efficient systems for genetic control of screwworm.
A One-Sided Competition Mathematical Model for the Sterile Insect Technique
14287A. Ben Dhahbi, Y. Chargui, S. M. Boulaaras and S. Ben Khalifa, Complexity, 2020:12. 2020-07-30 13:59:01.
We study a simple mathematical model describing the dynamics of a wild-type pest insects population experiencing competition from sterile insects (one-sided competition).
Genetically modified mosquitoes could be released in Florida
13587wqad.com, WQAD8, 2020-07-30 12:51:49.
Cases of dengue fever are on the rise in the Florida Keys. One biotech company wants to release genetically modified mosquitoes for a pilot program.
Nix alone is sufficient to convert female Aedes aegypti into fertile males and myo-sex is needed for male flight
13780A. Aryan, M. A. E. Anderson, J. K. Biedler, Y. M. Qi, J. M. Overcash, A. N. Naumenko, M. V. Sharakhova, C. H. Mao, Z. N. Adelman and Z. J. Tu, Proceedings of the National Academy of Sciences of the United States of America, 117:17702-17709. 2020-07-28 13:17:04.
Here, we report the generation of multiple transgenic lines that express Nix under the control of its own promoter. Genetic and molecular analyses of these lines provided insights unattainable from previous transient experiments. We show that the Nix transgene alone, in the absence of the M-locus, was sufficient to convert females into males with all male-specific sexually dimorphic features and male-like gene expression.
Why are scientists creating genetically modified mosquitoes?
13503The Week Staff, The Week, 2020-07-27 11:35:19.
The Week Staff. The Week (2020). Scientists plan to release altered mosquitoes designed to sabotage the species' ability to reproduce. Is this safe? Here's everything you need to know:
Florida Keys delays vote on release of 750 million genetically engineered mosquitoes after public outcry
13506D. Dukule, Friends of the Earth, 2020-07-22 12:41:45.
The Florida Keys Mosquito Control District (FKMCD) today delayed its vote on the proposed release of genetically engineered (GE) mosquitoes due to concerns over COVID-19. The decision to delay the vote follows public outcry and scientific dispute over the risks posed to public health and the environment by this experimental release. The approval would have permitted the British company Oxitec to release 750 million GE mosquitoes over a two-year period in Monroe County, Florida, starting as soon as this summer.
Release of genetically modified mosquitoes in the Florida Keys put on hold
13355D. Goodhue, Miami Herald, 2020-07-21 19:27:08.
Opponents of a plan to release millions of genetically modified mosquitoes in the Florida Keys landed a temporary win on Tuesday.
EPA approves field trials of genetically modified mosquito
13449A. Wernick, WBFO npr, 2020-07-17 16:18:01.
The Environmental Protection Agency has given biotech company Oxitec the go-ahead to test the effectiveness of genetically modified mosquitoes in parts of Florida and Texas. Oxitec has been developing genetically modified mosquitoes in hopes of reducing local populations of mosquitoes that carry dengue fever, yellow fever and the Zika virus. About 750,000 people die each year from mosquito-borne illnesses, making the insect indirectly responsible for more human deaths than any other animal in the world.
Researchers convert female mosquitoes to nonbiting males with implications for mosquito control
13194Virginia Tech, ScienceDaily, 2020-07-14 18:12:22.
Researchers convert female mosquitoes to nonbiting males with implications for mosquito control Virginia Tech researchers have proven that a single gene can convert female Aedes aegypti mosquitoes into fertile male mosquitoes and identified a gene needed for male mosquito flight
On Nonlinear Pest/Vector Control via the Sterile Insect Technique: Impact of Residual Fertility
14291M. S. Aronna and Y. Dumont, Bulletin of Mathematical Biology, 82:29. 2020-07-09 14:09:49.
We consider a minimalist model for the Sterile Insect Technique (SIT), assuming that residual fertility can occur in the sterile male population.
Beyone the buzz
13166C. Watson, The Journal Gazette, 2020-07-07 14:45:26.
Lately I have found I need to force myself to follow science stories about something besides the pandemic. A story I consider hopeful involves genetically modified mosquitoes; we are developing a new tool that can reduce disease and save lives. The goal is to dramatically reduce the mosquito population. Mosquitoes, by biting people and injecting some of their saliva, spread diseases such as yellow fever, dengue fever and malaria. Malaria kills about 600,000 people a year, mostly outside the U.S. The new tool being developed involves modifying the genes of male mosquitoes. The goal is to design a male mosquito that will behave typically, but whose female offspring die almost immediately.
GMO Mosquitoes to be launched in Florida
13162Administration, Editorials 360, 2020-07-01 14:38:18.
In June 2020, the Florida Division of Agriculture and Shopper Providers gave the go-ahead to a plan to launch thousands and thousands of genetically engineered mosquitoes within the Florida Keys this summer time to battle mosquito-borne diseases.1 The plan follows the EPA’s current granting of an experimental use allow (EUP) for the GMO (genetically modified organism) mosquitoes to allow them to be launched in Florida in 2020 and in Texas in 2021.2 The mosquitoes, engineered from the Aedes aegypti mosquito species,3 have been created by the U.S.-owned, Britain-based firm Oxitec, which originated as a spin-off firm from Oxford College and subsidiary of Intrexon.4 The corporate has additionally created genetically modified pink bollworm moths and GMO cabbage moths.
Who is afraid of genetically modified mosquitoes?
12738G. Odogwu, The PUNCH, 2020-06-25 13:27:54.
Genetically Modified Organisms have raised concerns in our clime, the same way they have in other countries of the world – where a clear line is drawn between the pro and the anti-GMO citizens. Nonetheless, this modern biotechnological technique is still at its infancy here. As of the moment, we can only boast of the development of the PBR cowpea as the only genetically modified food crop to be approved by the Nigerian government.
Mosquito district workshop focuses on Keys trials
12732S. Matthis, KEYSWEEKLY, 2020-06-25 13:21:52.
Now that the Oxitec “Friendly Mosquito” trials have been approved by the federal and state governments, it’s up to the Florida Keys Mosquito Control District to decide if, when and where to embrace the technology said to decrease the chances of mosquito-borne diseases such as dengue fever (there are two new cases in the Keys; see sidebar) and zika.
Genetically modified mosquitoes to be released in Florida and Texas
12735O. Ron, The Jerusalem Post, 2020-06-24 13:24:12.
A plan to release 750 million genetically modified mosquitoes in Florida and Texas has been approved, The Guardian reported. According to the plan, the Aedes aegypti mosquitoes will be released into the wild, as they contain a special protein that would kill female offspring, which are the ones who bite, and thus preventing the spread of such illnesses as dengue fever and Zika.
Before genetically modified mosquitoes are released, we need a better EPA
12720N. Kofler and J. Kuzma, The Boston Globe, 2020-06-22 13:07:55.
While the attention of the American public has rightfully been focused on the COVID-19 pandemic, its associated racial disparities, and broader issues of structural racism, the US government made a serious public health decision — one that could affect our health and our environment for generations to come. Last month, the US Environmental Protection Agency approved the release of genetically modified mosquitoes. Under a 2-year Experimental Use Permit, a company called Oxitec has been granted permission to release over 1 billion genetically modified mosquitoes across 6,600 acres in Florida and Texas.
Florida gives approval to the plan of releasing genetically modified mosquitoes.
12716V. Dalmia, The Andoverleader, 2020-06-20 21:01:10.
Mosquitoes have always been a huge problem for Florida residents. They are even more problematic in the Florida Key Region. It has even a dedicated mosquito department that is assigned with the task of controlling over 40 species of mosquitoes. But as technology progresses, we get new and newer methods to fight our problems. Gone are the days of pesticides.
Are Genetically Modified Mosquitoes Coming To Florida?
12726M. Taylor, Y100, 2020-06-19 13:13:35.
I'm not even going to lie, mosquitoes should be classified under domestic terrorism. The flying, biting bugs you can barely see wreak havoc on my life every single summer. I'm not sure if I'm allergic to them, but whenever I'm bit by them, that area of my skin swells up. It's the most annoying feeling in the world.
The Florida Keys are one step closer to getting genetically modified mosquitoes
12723D. Goodhue, Miami Herald, 2020-06-19 13:10:57.
An international biotech company is one step closer to being able to release genetically modified mosquitoes in the Florida Keys. The Florida Department of Agriculture and Consumer Services this week granted Oxitec an experimental use permit to release potentially millions of lab-made male Aedes aegypti mosquitoes throughout Monroe County. The goal is to wipe out the Keys population of the invasive bugs, which carry diseases like dengue fever, Zika and yellow fever. The Florida Department of Health reported a case of dengue fever in the Keys in March.
Genetically Modified Mosquitoes Approved For Insect Population Control In The U.S.
12705J. Blum, HUFFPOST, 2020-06-18 20:45:30.
Genetically modified mosquitoes with the ability to prevent other mosquitoes from spreading deadly diseases may be making their way to Florida backyards in the near future. British biotech group Oxitec announced on Tuesday that the company had won both federal and state approval to release its so-called “Friendly” mosquitoes in the U.S. on an experimental trial basis, expected to last until 2022, according to documents provided by the Environmental Protection Agency. The insects will first be released in Monroe County, Florida, and Oxitec has plans to also bring them tT Harris County, Texas.
Florida says ‘this is fine’ to release of genetically modified mosquitoes
12703J. K. Elliot, Global News, 2020-06-18 20:43:23.
That’s the question hanging over a recent decision by state regulators in Florida, which would allow the biotech company Oxitec to unleash hundreds of millions of genetically modified male mosquitoes in the Florida Keys. The lab-altered, patented insects are members of Aedes aegypti, the species of mosquito that spreads diseases such as yellow fever, malaria and chikungunya. However, they’ve been genetically altered to artificially reduce future mosquito populations.
Plan to Release GMO Mosquitoes Moves Ahead
12700A. Dier, newser, 2020-06-18 20:40:30.
A plan to set loose 750 million genetically modified mosquitoes in Florida and Texas will move forward despite concerns from environmentalists who liken it to a "Jurassic Park experiment." The non-biting male Aedes aegypti mosquitoes developed by British biotechnology company Oxitec contain a protein, passed to biting female offspring, that is designed to reduce the insect's chance of surviving into adulthood and therefore prevent the spread of mosquito-borne diseases including Zika and West Nile, reports the Guardian. The EPA has approved two trials, in which the mosquitoes are to be released in Florida's Monroe County this summer and in Texas' Harris County in 2021, though it's facing a lawsuit over its alleged failure to investigate the environmental impact, per the Hill. Facing similar complaints, Florida nonetheless approved its trial on Tuesday.
Genetically engineered mosquitoes get EPA approval for Florida release despite objections from environmental groups
12697S. LaMotte, CNN Health, 2020-06-18 20:37:52.
A genetically modified male mosquito named OX5034 has received both state and federal approval to be released into the Florida Keys now through 2022, against the objection of many local residents and a coalition of environmental advocacy groups. "The administration has used tax dollars and government resources for a Jurassic Park experiment, except without the island," said Jaydee Hanson, policy director at the International Center for Technology Assessment and Center for Food Safety, in a statement.
Florida Keys plans killer insect attack on disease-carrying mosquitoes
12693P. Brinkmann, UPI, 2020-06-18 20:33:39.
The Florida Keys is close to adding a new weapon to help control a mosquito-borne disease -- genetically modified mosquitoes that produce dead offspring. Outbreaks of dengue fever in the Keys in recent years prompted local authorities to consider the genetically modified bugs because the Aedes aegypti mosquito, which spreads that and other diseases, has shown resistance to pesticides.
Genetic breakdown of a Tet-off conditional lethality system for insect population control
13152Y. Zhao, M. F. Schetelig and A. M. Handler, Nature Communications, 11:3095. 2020-06-18 14:12:25.
Genetically modified conditional lethal strains have been created to improve the control of insect pest populations damaging to human health and agriculture. However, understanding the potential for the genetic breakdown of lethality systems by rare spontaneous mutations, or selection for inherent suppressors, is critical since field release studies are in progress. This knowledge gap was addressed in a Drosophila tetracycline-suppressible embryonic lethality system by analyzing the frequency and structure of primary-site spontaneous mutations and second-site suppressors resulting in heritable survivors from 1.2 million zygotes. Here we report that F1 survivors due to primary-site deletions and indels occur at a 5.8 × 10−6 frequency, while survival due to second-site maternal-effect suppressors occur at a ~10−5 frequency. Survivors due to inherent lethal effector suppressors could result in a resistant field population, and we suggest that this risk may be mitigated by the use of dual redundant, albeit functionally unrelated, lethality systems.
Plan to release genetically modified mosquitoes in Florida gets go-ahead
12695O. Milman, The Guardian, 2020-06-17 20:35:58.
A plan to release a horde of 750 million genetically modified mosqutioes in Florida and Texas is a step closer to fruition after a state regulator approved the idea, over the objections of many environmentalists.
Field performance of sterile male mosquitoes released from an uncrewed aerial vehicle
12708J. Bouyer, N. J. Culbert, A. H. Dicko, M. G. Pacheco, J. Virginio, M. C. Pedrosa, L. Garziera, A. T. M. Pinto, A. Klaptocz, J. Germann, T. Wallner, G. Salvador-Herranz, R. A. Herrero, H. Yamada, F. Balestrino and M. J. B. Vreysen, Science Robotics, 5:10. 2020-06-15 20:48:48.
Genetic control methods of mosquito vectors of malaria, dengue, yellow fever, and Zika are becoming increasingly popular due to the limitations of other techniques such as the use of insecticides. The sterile insect technique is an effective genetic control method to manage insect populations. However, it is crucial to release sterile mosquitoes by air to ensure homogeneous coverage, especially in large areas. Here, we report a fully automated adult mosquito release system operated from an uncrewed aerial vehicle or drone. Our system, developed and tested in Brazil, enabled a homogeneous dispersal of sterile male Aedes aegypti while maintaining their quality, leading to a homogeneous sterile-to-wild male ratio due to their aggregation in the same sites. Our results indicate that the released sterile males were able to compete with the wild males in mating with the wild females; thus, the sterile males were able to induce sterility in the native female population. The use of drones to implement the sterile insect technique will lead to improvements in areal coverage and savings in operational costs due to the requirement of fewer release sites and field staff.
EPA faces suit over plan to release genetically engineered mosquitoes
12457R. Frazin, The Hill, 2020-06-15 20:36:28.
The Environmental Protection Agency (EPA) is facing a lawsuit over its approval of a plan to release genetically modified mosquitoes in Florida and Texas
Fact check: Genetically modified mosquitoes are cleared for release in the US
12443A. Staver, USA Today, 2020-06-13 20:24:44.
The Environmental Protection Agency approved an experimental use permit May 1 that allows Oxitec to release genetically modified mosquitoes in the Florida Keys and Harris County, Texas, where Houston is located.
Scientists hope to release genetically-modified mosquitoes
12437Fox 13, Fox 13, 2020-06-09 20:18:09.
Apparently, scientists are interested in releasing genetically-modified mosquitoes in Florida in order to help battle the spread of certain diseases.
Scientist fight plant to release gene-hacked mosquitoes in TX, FL.
12429D. Robitzski, Futurism, 2020-06-09 20:11:41.
Over the next two years, the biotech company Oxitec plans to release millions of genetically modified mosquitoes in Florida and Texas in an attempt to stop the spread of diseases like dengue and Zika. The U.S. Environmental Protection Agency (EPA) has already approved the plan — but a group of biologists, ecologists, bioethicists, and sustainability researchers writes in an article for The Conversation that they’re concerned about the lack of oversight for the effort to effectively hack the ecosystem.
Company Receives Permit To Release Swarm Of Genetically Modified Mosquitoes In Florida
12446I. Monzon, International Business Times, 2020-06-08 20:26:29.
A federal agency has provided a biotech company with the proper permit to release a swarm of genetically altered mosquitoes in Florida as a way to curb the spread of diseases in the area. If the company receives the additional approvals, it might begin releasing the mosquitoes this summer. The mosquitoes were bred inside the laboratories of Oxitec, a British biotech firm. The company mainly focuses on transgenically modifying mosquitoes to carry lethal genes designed to be passed onto their offspring.
What else could 2020 bring to Florida? Genetically altered, lab bred mosquitoes
12426J. Haughey, The Center Square, 2020-06-08 20:10:06.
A British biotech company has received an experimental use permit from the U.S. Environmental Protection Agency to release millions of genetically modified mosquitoes in the Florida Keys this summer. The Florida Department of Agriculture and Consumer Services and the Florida Keys Mosquito Control District (FKMCD) board must approve the permit before Oxitec can proceed. The EPA approved Oxitec’s permit May 1 despite 31,174 people objecting to it and 56 people supporting it during a 30-day comment period that expired in mid-October
BUZZ OFF! Swarm of MILLIONS of gene-hacked mosquitoes will be unleashed across USA – to wipe out malaria with ‘death sex’
12423H. Pettit, The Sun, 2020-06-08 20:08:02.
MUTANT mosquitoes created in a lab to stop the spread of deadly diseases like malaria will be unleashed across the US this summer. The gene-hacked bugs, crafted by UK biotech company Oxitec, are designed to kill off or reduce local populations of mosquitoes by mating with them.
Genetically Modified Mosquitoes Cleared For Release In The US
12432M. Horowitz, Anonymous News, 2020-06-06 20:13:38.
A company called Oxitec has received an experimental use permit from the US Environmental Protection Agency (EPA), to release genetically modified mosquitos into the wild. This would be the first time that such an experiment was attempted within the borders of the US, and the permit would allow for the release of millions of genetically modified mosquitos each week over the next two years. The genetically modified insects will be released in Florida and Texas, but they will easily be able to travel throughout the country from there.
Genetically modified mosquitoes could be released in Florida and Texas beginning this summer – silver bullet or jumping the gun?
12409B. Allan, C. Stone, H. Tuten, J. Kuzma and N. Kofler, The Conversation, 2020-06-03 18:53:50.
On May 1, 2020, the company Oxitec received an experimental use permit from the U.S. Environmental Protection Agency to release millions of GM mosquitoes (labeled by Oxitec as OX5034) every week over the next two years in Florida and Texas. Females of this mosquito species, Aedes aegypti, transmit dengue, chikungunya, yellow fever and Zika viruses. When these lab-bred GM males are released and mate with wild females, their female offspring die. Continual, large-scale releases of these OX5034 GM males should eventually cause the temporary collapse of a wild population. However, as vector biologists, geneticists, policy experts and bioethicists, we are concerned that current government oversight and scientific evaluation of GM mosquitoes do not ensure their responsible deployment.
‘Just Add Water’ GM Mosquitoes Suppress Wild Population by 95%
12404H. Alber, 2020-05-27 18:49:43.
In order to reduce the spread of dengue, Oxitec releases genetically modified male Aedes mosquitoes into the environment. Once in the wild, these insects breed with local female mosquitoes and pass on a gene that causes female offspring to die at an early age. This method was reported to suppress the Aedes aegypti population by up to 96% in Brazil last year.
America’s Never-Ending Battle Against Flesh-Eating Worms
16665S. Zhang, The Atlantic, 2020-05-26 14:33:06.
The United States Department of Agriculture undertook what would ultimately become an immense, multidecade effort to wipe out the screwworms, first in the U.S. and then in Mexico and Central America—all the way down to the narrow strip of land that is the Isthmus of Panama. The eradication was a resounding success. But the story does not end there. Containing a disease is one thing. Keeping it contained is another thing entirely, as the coronavirus pandemic is now so dramatically demonstrating. To get the screwworms out, the USDA to this day maintains an international screwworm barrier along the Panama-Colombia border. The barrier is an invisible one, and it is kept in place by constant human effort. Every week, planes drop 14.7 million sterilized screwworms over the rainforest that divides the two countries. A screwworm-rearing plant operates 24/7 in Panama. Inspectors cover thousands of square miles by motorcycle, boat, and horseback, searching for stray screwworm infections north of the border. The slightest oversight could undo all the work that came before.
EPA Approves Genetically Modified Mosquito Trial For Florida Keys
11450Nancy Klingener, WLRN, 2020-05-07 18:22:34.
A plan to test genetically modified mosquitoes in the Florida Keys has received approval from the federal government.
Mutant mosquitoes one step closer to release in Florida, Texas this summer. Why?
11596K. Camero, The Charlotte Observer, 2020-05-07 15:45:03.
The U.S. Environmental Protection Agency (EPA) approved an experimental use permit for the British biotech company Oxitec to test the modified mosquitoes in the U.S. for the first time, according to a statement from the agency
US EPA OKs release of GM mosquitoes
11600A. Beer, Agrow Agribusiness, 2020-05-06 15:57:35.
he US EPA has granted an experimental use permit to US synthetic biology company Intrexon’s UK subsidiary, Oxitec, to test its genetically modified OX5034 Aedes aegypti mosquitoes.
Genetically Engineered Male Mosquitos to be Released in Florida and Other Parts of US to Curb Zika and Dengue Spread
11598Staff Reporter, The Science Times, 2020-05-06 15:47:02.
The Environmental Protection Agency has recently approved a new and controversial field test aimed at reducing their population.
Genetic Biocontrol – An Overview (video 13.13 min)
11398GeneConvene Global Collaborative, 2020-04-25 12:41:00.
This video explains what genetic biocontrol is and surveys various technologies that can be consider genetic biocontrol technologies. It offers a conceptual organization of the various technologies based on the potential of genetic biocontrol organisms to persist and spread in an environment. This video was produced by the GeneConvene Global Colaborative.
Guidance Framework for Testing the Sterile Insect Technique as a Vector Control Tool against Aedes-Borne Diseases
12451WHO & IAEA, WHO & IAEA, 2020-04-23 20:31:06.
This document is intended to be a comprehensive guide for programme managers tasked with recommending a “go/no-go” decision on testing, full deployment and scale-up of the sterile insect technique (SIT) in regions of the world affected by diseases transmitted by Aedes mosquitoes. However, the authors hope that the material presented herein will be used more widely—by scientists, decision makers, review groups and others.
Can we kill the dreaded mosquito? Do we even want to?
11228Stacey McKenna, Sierra, 2020-04-19 15:40:08.
As a major vector for disease, the mosquito has harmed more human beings than just about any other animal, and a changing climate is only boosting those numbers. As the range of disease-carrying species of mosquitoes expands, so does their ability to transmit the parasites and viruses that result in malaria, chikungunya, Zika, yellow fever, West Nile, and dengue fever. In 2018, the continental United States saw a 25 percent increase in severe, neuroinvasive cases of West Nile virus compared with a decade earlier. And over the past three decades, the CDC reports, the worldwide incidence of dengue fever has risen 30-fold.
Efficient production of male Wolbachia-infected Aedes aegypti mosquitoes enables large-scale suppression of wild populations
22639J. E. Crawford, D. W. Clarke, V. Criswell, M. Desnoyer, D. Cornel, B. Deegan, K. Gong, K. C. Hopkins, P. Howell, et al., Nature Biotechnology, 38:482-492. 2020-04-06 06:19:43.
The range of the mosquito Aedes aegypti continues to expand, putting more than two billion people at risk of arboviral infection. The sterile insect technique (SIT) has been used to successfully combat agricultural pests at large scale, but not mosquitoes, mainly because of challenges with consistent production and distribution of high-quality male mosquitoes. We describe automated processes to rear and release millions of competitive, sterile male Wolbachia-infected mosquitoes, and use of these males in a large-scale suppression trial in Fresno County, California. In 2018, we released 14.4 million males across three replicate neighborhoods encompassing 293 hectares. At peak mosquito season, the number of female mosquitoes was 95.5% lower (95% CI, 93.6–96.9) in release areas compared to non-release areas, with the most geographically isolated neighborhood reaching a 99% reduction. This work demonstrates the high efficacy of mosquito SIT in an area ninefold larger than in previous similar trials, supporting the potential of this approach in public health and nuisance-mosquito eradication programs.
Development of control and sterilization technology for bluegill by genome editing
20100M. A. Madsen, Nippon Suisan Gakkaishi, 86:100-100. 2020-03-31 09:55:36.
This article is in Japanese
Male-biased adult production of the striped fruit fly, Zeugodacus scutellata, by feeding dsRNA fpecific to Transformer-2
11271M. A. Al Baki, M. Vatanparast and Y. Kim, Insects, 11:211. 2020-03-28 19:17:02.
Sterile insect release technique (SIT) is effective for eradicating quarantine insects including various tephritid fruit flies. When SIT is used for fruit flies, it is challenging to remove females from sterile males due to oviposition-associated piercing damage. This study developed a sex transition technique by feeding double-stranded RNA (dsRNA) specific to a sex-determining gene, Transformer-2 (Zs-Tra2) of the striped fruit fly, Zeugodacus scutellata. Zs-Tra2 is homologous to other fruit fly orthologs. It is highly expressed in female adults. RNA interference (RNAi) of Zs-Tra2 by injecting or feeding its specific dsRNA to larvae significantly increased male ratio. Recombinant Escherichia coli cells expressing dsRNA specific to Zs-Tra2 were prepared and used to feed larvae to suppress Zs-Tra2 gene expression levels. When these recombinant bacteria were fed to larvae during the entire feeding stage, the test population was significantly male-biased. Some females treated with such recombinant E. coli exhibited mosaic morphological characters such as the presence of male-specific abdominal setae in females. This study proposes a novel technique by feeding dsRNA specific to Transformer-2 to reduce female production during mass-rearing of tephritid males for SIT.
The value of existing regulatory frameworks for the environmental risk assessment of agricultural pest control using gene drive
8194J. Romeis, J. Collatz, D. C. M. Glandorf and M. B. Bonsall, Environmental Science & Policy, 108:19-36. 2020-03-27 20:20:04.
The application of (synthetic) gene drives is a powerful tool to control populations of insects that are agricultural pests, vectors of diseases, or a threat to biodiversity potentially leading to the local or global eradication of a species. The potential use of gene drive organisms has triggered a heated discussion regarding their environmental impacts and regulatory oversight. However, experience exists in assessing the environmental impacts of a number of established agricultural pest control methods that require the release of living organisms, that provide high levels of area-wide control and that might be irreversible. This includes classical biological control, the sterile insect technique, the incompatible insect technique that is based on the cytoplasmic incompatibility caused by Wolbachia endosymbionts, and genetically modified insects containing self-limiting traits. The different technologies are described, the regulatory practice and experience is summarized and pathways through which these control technologies could harm valued ecosystem services are presented. With a focus on the application of gene drives in agriculture, using the invasive Drosophila suzukii (Diptera: Drosophilidae) as a case study we then discuss to what extent the existing frameworks could assist the risk assessment of insects carrying gene drives. We suggest that drawing on existing practices, experiences and legislative frameworks will provide a pragmatic and proportionate approach to evaluate the environmental risks of novel solutions based on gene drive technologies.
Editorial Expression of Concern: Transgenic Aedes aegypti Mosquitoes Transfer Genes into a Natural Population
16199B. R. Evans, P. Kotsakiozi, A. L. Costa-Da-Silva, R. S. Ioshino, L. Garziera, M. C. Pedrosa, A. Malavasi, J. F. Virginio, M. L. Capurro and J. R. Powell, Scientific Reports, 10:2. 2020-03-24 15:17:41.
Shortly after publication of this Article in September 2019, the Editors were alerted to concerns regarding the interpretation of the data and some of the conclusions.
The Buzz About Genetically Modified Mosquitoes – a podcast
7932The Scientist Creative Services Team, The Scientist, podcast. 2020-02-26 18:17:44.
Mosquito-borne diseases afflict a large portion of the world. In this month’s episode, we consider genetic methods to eradicate diseases such as Zika fever, Dengue fever, and malaria. We spoke with Omar Akbari, professor of Cell and Developmental Biology at the University of California, San Diego, to learn more.
Genetically engineered moths may save kale chips
7357C. Poku, BIOtechNOW, 2020-02-07 21:49:10.
Sea salt kale chips, bacon brussels sprouts, and buffalo cauliflower wings are under threat. Environmental activists will have you believe the biggest threat to our food system is pesticides. That’s not true, in fact, it’s insects—the very reason most pesticides are necessary. Insects are such a dangerous issue that Somalia recently declared a state of emergency as an “unprecedented” swarm of locusts is raising alarms about famine. Climate change has led to a rampant increase in bugs like locusts and moths, that threaten our food, and mosquitoes and ticks, that threaten people. A recent CNN article explains that diamondback moths are one of the most damaging insects because of their high reproduction rate and resistance to most insecticides.
Phased Conditional Approach for Mosquito Management Using Sterile Insect Technique
7351J. Bouyer, H. Yamada, R. Pereira, K. Bourtzis and M. J. B. Vreysen, Trends in Parasitology, 2020-02-05 21:36:11.
Mosquito-borne diseases represent a major threat to humankind. Recently, the incidence of malaria has stopped decreasing while that of dengue is increasing exponentially. Alternative mosquito-control methods are urgently needed. The sterile insect technique (SIT) has seen significant developments recently and may play an important role. However, testing and implementing SIT for vector control is challenging, and a phased conditional approach (PCA) is recommended, that is, advancement to the next phase depends on completion of activities in the previous one. We herewith present a PCA to test the SIT against mosquitoes within an area-wide-integrated pest-management programme, taking into account the experience gained with plant and livestock pests and the recent developments of the technique against mosquitoes.
Genetic Variation and Potential for Resistance Development to the tTA Overexpression Lethal System in Insects
7939K. E. Knudsen, W. R. Reid, T. M. Barbour, L. M. Bowes, J. Duncan, E. Philpott, S. Potter and M. J. Scott, G3: Genes|Genomes|Genetics, Early Online:g3.400990.2020. 2020-02-05 20:27:28.
Release of insect pests carrying the dominant lethal tetracycline transactivator (tTA) overexpression system has been proposed as a means for population suppression. High levels of the tTA transcription factor are thought to be toxic due to either transcriptional squelching or interference with protein ubiquitination. Here we utilized the Drosophila melanogaster Genetic Reference Panel (DGRP) to examine the influence of genetic variation on the efficacy of a female-specific tTA overexpression system. The level of female lethality between DGRP lines varied from 11 to 97% with a broad sense heritability of 0.89. A genome-wide association analysis identified 192 allelic variants associated with high or low lethality (p<10-5), although none were significant when corrected for multiple testing. 151 of the variants fell within 108 genes that were associated with several biological processes including transcription and protein ubiquitination. In four lines with high female lethality, tTA RNA levels were similar or higher than in the parental tTA overexpression strain. In two lines with low lethality, tTA levels were 2-fold lower than in the parental strain. However, in two other lines with low lethality, tTA levels were only 0-30% lower. RNAseq analysis identified genes that were up or downregulated in the low female lethal lines compared to the four high lethal lines. For example, genes associated with RNA processing and rRNA maturation were significantly upregulated in low lethal lines. Our data suggest that standing genetic variation in an insect population could provide multiple mechanisms for resistance to the tTA overexpression system.
Genetically engineered moths have been released into the wild to wipe out pests
7360K. Rogers, CNN, 2020-02-03 21:55:17.
Genetically modified diamondback moths designed to wipe out wild pest populations were released in fields for the first time in New York state. Diamondback moths are migratory pests found in the Americas, Europe, New Zealand and Southeast Asia, but especially in areas where crops can be grown yearround. In these parts -- where it's not too hot nor too cold -- are where diamondback moths cause the greatest problems, including billions of dollars in damages to cruciferous crops such as cabbage, broccoli, cauliflower and canola. They're one of the most damaging insects because of their high reproduction rate and resistance to most insecticides.
Genetically modified butterflies could herald a new era in crop protection
7245Science News,, Science News, 2020-02-01 16:02:30.
New study highlights successful test including field release of genetically modified butterflies. Scientists believe this success could pave the way for an effective and sustainable approach to pest control in crops. The butterfly in question is the cruciferous moth ( Plutella xylostella ), or cabbage moth, a species of moth (butterfly) of the family Plutellidae. The agricultural industry has been trying for decades to find organic and environmentally friendly ways to fight the cruciferous moth, a species largely resistant to insecticides.
World’s First Genetically Modified Moths Released to Nature
7248M. Cage, SOMAG News, 2020-01-30 16:07:06.
There are many insect species that harm agricultural products in the world. One of them is diamond moths. Genetically modified moths were used to control these moths, which are harmful to many plants. Plutella xylostella or also known as diamond moths; One of the most harmful and destructive insects for plants such as cauliflower, cabbage, broccoli and canola. This creature, which is also very resistant to pesticides, causes great damage to the plants it dips. Especially in China, this insect seriously undermines the growing of cabbage, one of the country’s most important crops.
GMO diamondback moth shows promise as sustainable pest control tool in first ever open-field release
7262Cornell University, Genetic Literacy Project, 2020-01-29 16:35:41.
A newly published study reports a successful, first-ever open-field release of a self-limiting, genetically engineered diamondback moth, stating that it paves the way for an effective and sustainable approach to pest control. The diamondback moth, also known as Plutella xylostella, is highly damaging to brassica crops such as cabbage, broccoli, cauliflower and canola. This new strain of diamondback moth, developed by Oxitec Ltd, is modified to control pest diamondback moth in a targeted manner. The study showed the engineered strain had similar field behaviors to unmodified diamondback moths, with results offering promise for future protection of farmers’ brassica crops.
Scientists have released genetically modified moths
7259N. Kumar, The Times Hub, 2020-01-29 16:32:32.
In the US, the researchers decided to test emerging from genetic modification Diamondback moth, placing it in field conditions. The work was conducted by experts from new York, representing Cornell University.
GM Insects on the Horizon
7256E. Unglesbee, Progressive Farmer, 2020-01-29 16:22:18.
Diamondback moths would do well to be wary of potential mates in the years to come. Scientists recently completed the first successful field testing of a genetically modified (GM) "self-limiting" insect in the U.S., using this species. When the GM male diamondback moths are released and mate with wild female moths, they pass on a gene that causes all female offspring from the match to die in the early larval stages.
Male moths genetically modified to kill females released in the wild
7253M. Le Page, New Scientist, 2020-01-29 16:14:01.
Genetically modified male diamondback moths designed to wipe out pest populations have been released in New York state. The field trial shows that these GM moths, whose female offspring die soon after hatching, could help control this major crop pest. Oxitec, the British biotechnology company behind the trial, has already carried out field trials of this method for controlling mosquitoes that spread diseases such as dengue. However, the moth field trial is the first for a crop pest, the company says.
First Field Release of a Genetically Engineered, Self-Limiting Agricultural Pest Insect: Evaluating Its Potential for Future Crop Protection
7251A. M. Shelton, S. J. Long, A. S. Walker, M. Bolton, H. L. Collins, L. Revuelta, L. M. Johnson and N. I. Morrison, Frontiers in Bioengineering and Biotechnology, 7:1-15. 2020-01-29 16:10:21.
Alternative, biologically-based approaches for pest management are sorely needed and one approach is to use genetically engineered insects. Herein we describe a series of integrated field, laboratory and modeling studies with the diamondback moth, Plutella xylostella, a serious global pest of crucifers. A “self-limiting” strain of Plutella xylostella (OX4319L), genetically engineered to allow the production of male-only cohorts of moths for field releases, was developed as a novel approach to protect crucifer crops. Wild-type females that mate with these self-limiting males will not produce viable female progeny. Our previous greenhouse studies demonstrated that releases of OX4319L males lead to suppression of the target pest population and dilution of insecticide-resistance genes. We report results of the first open-field release of a non-irradiated, genetically engineered self-limiting strain of an agricultural pest insect. In a series of mark-release-recapture field studies with co-releases of adult OX4319L males and wild-type counterparts, the dispersal, persistence and field survival of each strain were measured in a 2.83 ha cabbage field. In most cases, no differences were detected in these parameters. Overall, 97.8% of the wild-type males and 95.4% of the OX4319L males recaptured dispersed <35 m from the release point. The predicted persistence did not differ between strains regardless of release rate. With 95% confidence, 75% of OX4319L males released at a rate of 1,500 could be expected to live between 3.5 and 5.4 days and 95% of these males could be expected to be detected within 25.8–34.9 m from the release point. Moth strain had no effect on field survival but release rate did. Collectively, these results suggest similar field behavior of OX4319L males compared to its wild-type counterpart. Laboratory studies revealed no differences in mating competitiveness or intrinsic growth rates between the strains and small differences in longevity. Using results from these studies, mathematical models were developed that indicate release of OX4319L males should offer efficacious pest management of P. xylostella. Further field studies are recommended to demonstrate the potential for this self-limiting P. xylostella to provide pest suppression and resistance management benefits, as was previously demonstrated in greenhouse studies.
Genetic Control of Mosquitoes
5588Alphey, L., Annual Review of Entomology, 59:205-224. 2019-12-16 19:01:55.
Genetics can potentially provide new, species-specific, environmentally friendly methods for mosquito control. Genetic control strategies aim either to suppress target populations or to introduce a harm-reducing novel trait. Different approaches differ considerably in their properties, especially between self-limiting strategies, where the modification has limited persistence, and self-sustaining strategies, which are intended to persist indefinitely in the target population and may invade other populations. Several methods with different molecular biology are under development and the first field trials have been completed successfully.
Community Engagement Prior to a Small-Scale Pilot of the Sterile Insect Technique in Kwazulu-Natal, South Africa 2018
25918P. N. Manana, J. Zikhali, D. Dlamini, S. Gumede, N. Mabaso, T. Mpungose and G. Munhenga, Journal of Public Health and Disease Prevention, 2. 2019-12-16 13:14:53.
Approximately 165 000 listeners were engaged during two 30 minute radio interviews at a local radio station. Two hundred and fifty farm workers, several outpatients from primary health care facilities and 1400 secondary school pupils were given education on malaria transmission and control strategies including SIT. Furthermore, two road shows; one in areas around Mamfene and a second at KwaPhuza market, were done. In total, 447 falciparum-specific rapid diagnostic tests were conducted with 20 people testing positive. These patients were immediately treated for malaria. Conclusions: The campaigns showed that the majority of community members are informed concerning malaria transmission and control. However, there is a lack of understanding regarding the SIT as a vector control option. A more extensive public awareness programme on SIT as a vector control strategy is recommended to prepare the community of Mamfene for future small field pilot sterile male mosquito releases.
Mass-Rearing of Drosophila suzukii for Sterile Insect Technique Application: Evaluation of Two Oviposition Systems
17766F. Sassù, K. Nikolouli, S. Caravantes, G. Taret, R. Pereira, M. J. B. Vreysen, C. Stauffer and C. Cáceres, Insects, 10. 2019-12-12 15:07:36.
Drosophila suzukii (Diptera: Drosophilidae) is an invasive pest of a wide range of commercial soft-skinned fruits. To date, most management tactics are based on spraying of conventional and/or organic insecticides, baited traps, and netting exclusion. Interest has been expressed in using the sterile insect technique (SIT) as part of area-wide integrated pest management (AW-IPM) programs to control D. suzukii infestations. Mass-rearing protocols are one of the prerequisites for successful implementation of the SIT. To establish mass-rearing methods for this species, two different egg-collection systems were developed and compared with respect to the number of eggs produced, egg viability, pupa and adult recovery, adult emergence rate, and flight ability. Female flies kept in cages equipped with a wax panel produced significantly more eggs with higher viability and adult emergence rate, as compared to the netted oviposition system. The wax panel system was also more practical and less laborious regarding the collection of eggs. Furthermore, the wax panel oviposition system can be adapted to any size or design of an adult cage. In conclusion, this system bears great promise as an effective system for the mass production of D. suzukii for SIT.
The Competitive Mating of Irradiated Brown Marmorated Stink Bugs, Halyomorpha halys, for the Sterile Insect Technique
17772D. M. Suckling, M. Cristofaro, G. Roselli, M. C. Levy, A. Cemmi, V. Mazzoni, L. D. Stringer, V. Zeni, C. Ioriatti and G. Anfora, Insects, 10. 2019-11-16 15:14:41.
The sterility of eggs and nymphs from gamma-irradiated male Halyomorpha halys was investigated to determine the potential for the sterile insect technique (SIT). Males irradiated at 0, 16, 24 and 32 Gy were placed with untreated virgin females, and egg sterility was determined, showing 54.3% at 16 Gy. The percentage of sterility from irradiation was 26 percent lower than previous results from the USA and the variance was very high. Competitive overflooding ratio trials between irradiated virgin males and fertile virgin males at a 5:1 ratio resulted in the expected egg sterility, indicating competitive performance by irradiated males. By July and August, older, irradiated overwintered males were significantly less competitive than similar, non-irradiated males. There is a need to revisit the irradiation delivery method to achieve proper precision around the paternal dose required for an expected >80% egg sterility and subsequent ~99% endpoint sterility estimated at adult emergence in the F1 phase. These results suggest that the mating competitiveness and competency of males after irradiation at 16 Gy is not limiting to the sterile insect technique for suppression. A wild harvest of overwintering males using the aggregation pheromone, followed by irradiation and male release, might replace rearing. Mass-collected, sterilized bugs could be transported from an area of high H. halys density and shipped for release to enable suppression or eradication elsewhere. This concept is under development but further work is needed now to understand the difference in results between the US and Italian irradiators and increase the reliability of dosimetry.
Transgenic Aedes aegypti Mosquitoes Transfer Genes into a Natural Population
16197B. R. Evans, P. Kotsakiozi, A. L. Costa-da-Silva, R. S. Ioshino, L. Garziera, M. C. Pedrosa, A. Malavasi, J. F. Virginio, M. L. Capurro and J. R. Powell, Scientific Reports, 9:6. 2019-09-10 15:09:04.
We genotyped the release strain and the target Jacobina population before releases began for >21,000 single nucleotide polymorphisms (SNPs). Genetic sampling from the target population six, 12, and 27-30 months after releases commenced provides clear evidence that portions of the transgenic strain genome have been incorporated into the target population. Evidently, rare viable hybrid offspring between the release strain and the Jacobina population are sufficiently robust to be able to reproduce in nature. The release strain was developed using a strain originally from Cuba, then outcrossed to a Mexican population. Thus, Jacobina Ae. aegypti are now a mix of three populations. It is unclear how this may affect disease transmission or affect other efforts to control these dangerous vectors. These results highlight the importance of having in place a genetic monitoring program during such releases to detect un-anticipated outcomes.
Engineered action at a distance: Blood-meal-inducible paralysis in Aedes aegypti
16651R. E. Haghighat-Khah, T. Harvey-Samuel, S. Basu, O. StJohn, S. Scaife, S. Verkuijl, E. Lovett and L. Alphey, PLOS Neglected Tropical Diseases, 13:e0007579. 2019-09-03 20:37:29.
Here we demonstrate that it is possible to engineer ‘non-cell autonomous’ effectors–that is where the effect (e.g. the action of a toxic protein) can act on cells distant from the tissues in which they are originally expressed. To achieve this we utilised the endogenous cell secretory pathway to engineer a novel control phenotype–blood-meal inducible (i.e. late-acting, female-specific) reversible paralysis. The logic behind engineering such ‘action at a distance’ phenotypes will extend to a variety of other pest insects and control phenotypes.
Sex Sorting for Pest Control: It’s Raining Men!
17064C. Lutrat, D. Giesbrecht, E. Marois, S. Whyard, T. Baldet and J. Bouyer, Trends in Parasitology, 35:649-662. 2019-06-26 14:04:15.
In the pursuit of better pest- and vector-control strategies, attention returns to an old proven technology, the sterile insect technique (SIT) and related insect population-suppression methods. A major obstacle for any of these approaches that involves the release of sterile males is the separation of males from females during the mass rearing stage, in order to improve the cost-efficiency of these methods and to prevent the release of biting and disease-vectoring females. This review describes recent sex-sorting developments in dipteran flies with an emphasis on assessing the suitability of these methods for large-scale rearing of male vectors for mass release.
A synthetic male-specific sterilization system using the mammalian pro-apoptotic factor in a malaria vector mosquito
16645D. S. Yamamoto, M. Sumitani, K. Kasashima, H. Sezutsu, H. Matsuoka and H. Kato, Scientific Reports, 9:11. 2019-06-03 19:52:01.
We produced a transgenic mosquito line that expresses mouse Bax under the control of this testis-specific promoter. Transgenic mosquito males exhibited aberrant testes without functional sperm and complete sterility, whereas transgenic females maintained normal fecundity. Despite their abnormal testes, the transgenic males maintained normal function of male accessory glands and typical mating behaviour. As a result of mating with these males, females showed refractoriness to further mating. These results suggest that transgenic males induce female sterility via mating. The mosquito is one of the most important disease vectors, and the control of their population benefits global public health.
Sterile insect technique field trials to eliminate malaria under way
25913Anonymous, SA Department of Science and Innovation, 2018-10-29 13:06:00.
The first South African research trial for the biological control of mosquitoes using the sterile insect technique started in Jozini in KwaZulu-Natal earlier this month, with funding from the Department of Science and Technology. South Africa is making significant progress in reducing the incidence of malaria, and is now at a level where the country in a prime position to begin with complementary vector control strategies that address the problem of insecticide resistance. However, indoor residual spraying (IRS) using DDT and pyrethroid insecticides, while effective in controlling the disease, is unlikely to eliminate malaria on its own. IRS targets mainly indoor feeding and resting mosquitoes, and is not effective against vectors that feed and rest outdoors such as Anopheles arabiensis, which is a major contributor to outdoor transmission in South Africa's malaria-affected provinces. One of the supplementary methods being explored is the use of the sterile insect technique (SIT). This works like birth control to suppress mosquito populations and reduce the spread of malaria. The technique involves the mass-rearing and sterilisation of male mosquitoes before they are released in the wild.
Agricultural production: assessment of the potential use of Cas9-mediated gene drive systems for agricultural pest control
13796M. J. Scott, F. Gould, M. Lorenzen, N. Grubbs, O. Edwards and D. O’Brochta, Journal of Responsible Innovation, 5:S98-S120. 2018-01-24 15:43:20.
To highlight how gene drives could be useful for control of agricultural insect pests, we selected species that are pests of animals (New World screwworm), plants (spotted wing Drosophila, diamondback moth, Bemisia tabaci whitefly), or stored grains (red flour beetle). We provide examples of gene drives that target specific genes including female-essential genes. Further, we discuss issues related to containment in the laboratory and eventual field testing of strains harboring a Cas9-mediated gene drive system.
The sterile male release approach as a method to control invasive amphibian populations: a preliminary study on Lithobates catesbeianus
13727S. Descamps and A. De Vocht, Management of Biological Invasions, 8:361-370. 2017-09-14 18:55:55.
Widespread populations of the invasive species Lithobates catesbeianus (American bullfrog) are present in different parts of the world and are difficult to control. This study investigated the possibility to sterilize male individuals of this species in order to use the sterile male release technique in controlling these invasive populations.
A secret weapon against Zika and other mosquito-borne diseases
6372Nina Federoff, TEDxMidAtlantic, 2017-07-15 15:37:47.
Where did Zika come from, and what can we do about it? Molecular biologist Nina Fedoroff takes us around the world to understand Zika's origins and how it spread, proposing a controversial way to stop the virus -- and other deadly diseases -- by preventing infected mosquitoes from multiplying.
The IAEA and Food – Tsetse Fly Eradication – Senegal
25659International Atomic Energy Agency, IAEA/FAO, 2017-06-21 14:02:20.
Senegal has successfully integrated the Sterile Insect Technique into its tsetse fly control project in the Niayes region. This nuclear technique suppresses or even eradicates insect pest by using radiation to sterilize primarily males. The disease that tsetse flies transmit can kill livestock or make them sick.
Area-wide Integrated Pest Management
13603Food and Agriculture Organization of the United Nations (FAO), International Atomic Energy Agency, 2017-05-22 13:34:46.
Throughout history, people have had to fight insect pests to reduce diseases, minimize food losses, protect agricultural trade or simply to avoid the nuisance of stinging, biting and buzzing bugs. Insect pest control is usually implemented locally in individual fields or properties. These uncoordinated efforts often prove inefficient since they only suppress a proportion of the targeted pest population. Pests from nearby untreated areas remain unscathed and can re-enter the treated areas, the damage continues, and people have little choice but to apply the control measures again and again to protect their livelihoods. Area-wide pest management provides a more cost-effective and sustainable approach by proactively targeting entire pest populations. In this way, pest populations can be contained at low levels for longer periods and pest management methods can be integrated that are less reliant on pesticides and that better address ecological and environmental concerns.
Concept and history of genetic control
6014Scott, M. J. and Benedict, M. Q., Genetic Control of Malaria and Dengue, 2:31-54. 2016-12-30 20:16:45.
Genetic control of insects is an established method, mainly for insects that are important crop and veterinary pests such as medflies and screwworm. Efforts to use the same technologies against insects of medical importance, especially mosquitoes, have had limited success. The successes against mosquitoes have been accomplished using forms of both conventional and modern methods, both of which are promising. In this chapter, we provide highlights of the development of genetic control of agricultural pests and describe how the development of methods against mosquitoes reflects those advances. While admiring successful genetic control programs is motivating, we suggest that much can also be learned from both past successful and failed efforts, as doing so will increase our ability to improve future activities.
Mating competitiveness of sterile genetic sexing strain males (GAMA) under laboratory and semi-field conditions: Steps towards the use of the Sterile Insect Technique to control the major malaria vector Anopheles arabiensis in South Africa
25911G. Munhenga, B. D. Brooke, J. R. L. Gilles, K. Slabbert, A. Kemp, L. C. Dandalo, O. R. Wood, L. N. Lobb, D. Govender, M. Renke and L. L. Koekemoer, Parasites and Vectors, 9:122. 2016-03-02 13:00:23.
Anopheles arabiensis Patton is primarily responsible for malaria transmission in South Africa after successful suppression of other major vector species using indoor spraying of residual insecticides. Control of An. arabiensis using current insecticide based approaches is proving difficult owing to the development of insecticide resistance, and variable feeding and resting behaviours. The use of the sterile insect technique as an area-wide integrated pest management system to supplement the control of An. arabiensis was proposed for South Africa and is currently under investigation. The success of this technique is dependent on the ability of laboratory-reared sterile males to compete with wild males for mates. As part of the research and development of the SIT technique for use against An. arabiensis in South Africa, radio-sensitivity and mating competitiveness of a local An. arabiensis sexing strain were assessed.
The Sterile Insect Technique
27105IAEA/FAO, 2015-08-14 10:52:33.
For over 50 years, the Sterile Insect Technique (SIT) has been successfully used around the world to tackle pests that destroy fruit and kill livestock. The method uses radiation to sterilize male flies, which are mass-produced in rearing facilities. Large numbers of sterile males are released into a target area, where they mate with wild females. No offspring are produced, and the wild fly population declines over time. Once established, this technique provides sustainable, cost-effective and environmentally-friendly insect control.
The Trojan Female Technique for pest control: a candidate mitochondrial mutation confers low male fertility across diverse nuclear backgrounds in Drosophila melanogaster
13733D. K. Dowling, D. M. Tompkins and N. J. Gemmell, Evolutionary Applications, 8:8710880. 2015-07-15 19:28:56.
The Trojan Female Technique (TFT) was recently proposed as a prospective approach to biological pest control. However, applicability of the TFT relies on mitochondrial mutations whose male-sterilizing effects are general across nuclear genomic contexts. We test this assumption, expressing the candidate TFT-mutation bearing haplotype alongside a range of nuclear backgrounds and comparing its fertility in males, relative to that of control haplotypes
Back to the future: the sterile insect technique against mosquito disease vectors
25916R. S. Lees, J. R. L. Gilles, J. Hendrichs, M. J. B. Vreysen and K. Bourtzis, Current Opinion in Insect Science, 10:156-162. 2015-06-03 13:09:41.
With the global burden of mosquito-borne diseases increasing, and some conventional vector control tools losing effectiveness, the sterile insect technique (SIT) is a potential new tool in the arsenal. Equipment and protocols have been developed and validated for efficient mass-rearing, irradiation and release of Aedines and Anophelines that could be useful for several control approaches. Assessment of male quality is becoming more sophisticated, and several groups are well advanced in pilot site selection and population surveillance. It will not be long before SIT feasibility has been evaluated in various settings. Until perfect sexing mechanisms exist, combination of Wolbachia-induced phenotypes, such as cytoplasmic incompatibility and pathogen interference, and irradiation may prove to be the safest solution for population suppression.
Genetic Control of Mosquitoes.
5597Alphey, L., Annual Review of Entomology, 59:205-224. 2014-12-17 15:50:24.
Genetics can potentially provide new, species-specific, environmentally friendly methods for mosquito control. Genetic control strategies aim either to suppress target populations or to introduce a harm-reducing novel trait. Different approaches differ considerably in their properties, especially between self-limiting strategies, where the modification has limited persistence, and self-sustaining strategies, which are intended to persist indefinitely in the target population and may invade other populations. Several methods with different molecular biology are under development and the first field trials have been completed successfully.
Genetic control of invasive fish: technological options and its role in integrated pest management
4158Thresher, REH, K.; Bax, N. J.; Teem, J.; Benfey, T. J.; Gould, F., Biological Invasions, 16:1201-1216. 2014-01-16 00:00:00.
Genetic options for the control of invasive fishes were recently reviewed and synthesized at a 2010 international symposium, held in Minneapolis/St. Paul, MN, USA. The only option currently available "off-the-shelf'' is triploidy, which can be used to produce sterile males for a release program analogous to those widely and successfully used for biological control of insect pests. However, the Trojan Y and several recombinant options that heritably distort pest population sex ratios are technologically feasible, are at or are close to proof-of-concept stage and are potentially much more effective than sterile male release programs. All genetic options at this stage require prolonged stocking programs to be effective, though gene drive systems are a potential for recombinant approaches. They are also likely to differ in their current degree of social acceptability, with chromosomal approaches (triploidy and Trojan Y) likely to be the most readily acceptable to the public and least likely to require changes in legislative or policy settings to be implemented. Modelling also suggests that the efficacy of any of these genetic techniques is enhanced by, and in turn non-additively enhance, conventional methods of pest fish control.
The Trojan female technique: a novel, effective and humane approach for pest population control
13614N. J. Gemmell, A. Jalilzadeh, R. K. Didham, T. Soboleva and D. M. Tompkins, Proceedings of the Royal Society B: Biological Sciences, 280:20132549. 2013-12-22 13:07:01.
We use mathematical models to test a new twist on the SMT, using maternally inherited mitochondrial (mtDNA) mutations that affect male, but not female reproductive fitness. ‘Trojan females’ carrying suchmutations, and their female descendants, produce ‘sterile-male’-equivalents under natural conditions over multiple generations. We find that the Trojan female technique (TFT) has the potential to be a novel humane approach for pest control.
Swarming and mating behavior of male Anopheles arabiensis Patton (Diptera: Culicidae) in an area of the Sterile Insect Technique Project in Dongola, northern Sudan
25815M. M. Hassan, H. M. Zain, M. A. Basheer, H. E. F. Elhaj and B. B. El-Sayed, Acta Tropica, 132:S64-S69. 2013-11-27 08:57:21.
The problems facing the conventional mosquito control methods including resistance to insecticides have led to the development of alternative methods such as the Sterile Insect Technique (SIT) to suppress populations of the malaria vector Anopheles arabiensis in northern Sudan. This method entails the release of large numbers of irradiated males to compete against wild conspecifics for mating with virgin females in the field. The swarming and mating behaviors of this species were conducted at two field sites during the period 2009-2012 in Dongola, northern Sudan. Observations were made in the field sites and in a contained semi-field enclosure. In addition, participation of released irradiated-marked males in the swarms of wild mosquito was investigated. Swarms were observed on sunset in the vicinity of larval habitats around irrigation channel and stopped with the onset of the darkness about 21-25 min after the start. Swarms were observed above visual markers such as palm trees, bare ground, and manure. Several couples were observed leaving the swarms in copula in the direction of the sunlight. The majority of copulations were observed within 12-15 min of the start of swarming. Relatively low insemination rates (28%) of females collected from coupling pairs were observed. Irradiated-marked males were observed to join the natural swarms regularly, indicating their probable competitiveness with the other wild males. These findings enhance the feasibility of staging an SIT campaign against malaria vector in Northern State-Sudan. Copyright (C) International Atomic Energy Agency 2013. Published by Elsevier B.V. All rights reserved.
Demographic effects on the use of genetic options for the control of mosquitofish, Gambusia holbrooki
11528R. E. Thresher, M. Canning and N. J. Bax, Ecological Applications, 23:801-814. 2013-06-01 15:57:26.
This study tests the sensitivity of genetically based pest control options based on sex ratio distortion to intra-and intersexual aggressive interactions that affect male and female survival and fitness. Data on these interactions and their impacts were gathered for the mosquitofish Gambusia holbrooki (Poeciliidae), a promiscuous species with a strongly male-biased operational sex ratio and well-documented male harassment of females. The experimental design consisted of an orthogonal combination of two population densities and three sex ratios, ranging from strongly male-biased to strongly female-biased, and long-term observations of laboratory populations. Contrary to expectations, the number of males in a population had little evident effect on population demographics. Rather, the density of adult females determined population fecundity (as a result of a stock-recruitment relationship involving females, but not males), constrained male densities (apparently as a result of cannibalism or intersexual aggression), and regulated itself (most likely through effects of intrasexual aggression on female recruitment). The principal effect of males was to constrain their own densities via effects of male-male aggression on adult male mortality rates. Through use of a realistically parameterized genetic/demographic model, we show that of three different genetic options applied to control G. holbrooki, one based on recombinant sex ratio distortion (release of Female Lethal carriers) is marginally more efficient than a sterile male release program, and both outperform an option based on chromosomal sex ratio distortion (Trojan W). Nonlinear dependence of reproductive rate on female density reduces the efficacy of all three approaches. The major effect of intra-and intersexual aggression is mediated through females, whose interactions reduce female numbers and increase the efficacy of a control program based on sex ratio. Socially mediated male mortality has a small impact on control programs due to operational sex ratios that are heavily male-biased. The sensitivity of sex ratio-based control options to social factors will depend on the mating system of the targeted pest, but evidence of widespread density-dependent population regulation suggests that, for most species, the effects of elevated adult mortality (due to intra-and intersexual aggression) on control programs are likely to be slight.
Evaluating the potential of the sterile insect technique for malaria control: relative fitness and mating compatibility between laboratory colonized and a wild population of Anopheles arabiensis from the Kruger National Park, South Africa
25909G. Munhenga, B. D. Brooke, T. F. Chirwa, R. H. Hunt, M. Coetzee, D. Govender and L. L. Koekemoer, Parasites and Vectors, 4:208. 2011-10-31 12:48:58.
The successful suppression of a target insect population using the sterile insect technique (SIT) partly depends on the premise that the laboratory insects used for mass rearing are genetically compatible with the target population, that the mating competitiveness of laboratory reared males is at least comparable to that of their wild counterparts, and that mass rearing and sterilization processes do not in themselves compromise male fitness to a degree that precludes them from successfully competing for mates in the wild. This study investigated the fitness and sexual cross-compatibility between samples of field collected and laboratory reared An. arabiensis under laboratory conditions.
Field performance of engineered male mosquitoes
6401A. F. Harris, D. Nimmo, A. R. McKemey, N. Kelly, S. Scaife, C. A. Donnelly, C. Beech, W. D. Petrie and L. Alphey, Nature Biotechnology, 29:1034-1037. 2011-10-30 16:54:55.
Mass-release of sterile male mosquitoes is a promising option for controlling dengue and malaria, but it has never been shown that lab-raised transgenic males can compete effectively with their wild counterparts outside laboratory conditions. Promising results from a restricted field trail now suggest the feasibility of extending the approach for large-scale mosquito-control programs.
Why RIDL is not SIT
26699W. C. Black, L. Alphey and A. A. James, Trends in Parasitology, 27:362-370. 2011-08-01 07:23:46.
History teaches that sterile insect technique (SIT) is a feasible strategy for mosquito population suppression. Female killing (FK) technologies developed later theoretically had greater potential than SIT, but depended upon chromosomal translocations. Unfortunately these were genetically unstable. New transgenic strategies have been misinterpreted as a replacement for SIT. Instead these strategies provide a means to revisit FK. Conditional lethal mutations inserted into mosquito genomes allow for adjustment of the age of mortality, female-specific lethality, bisexual lethality and manipulation of germline-specific gene expression. A recent Aedes aegypti case study demonstrates the viability of one of these new transgenic strategies.
Ethical, legal and social aspects of the approach in Sudan
25823B. B. El Sayed, C. A. Malcolm, A. Babiker, E. M. Malik, M. A. H. El Tayeb, N. S. Saeed, A. H. D. Nugud and B. G. J. Knols, Malaria Journal, 8:S3. 2009-11-16 10:10:31.
The global malaria situation, especially in Africa, and the problems frequently encountered in chemical control of vectors such as insecticide resistance, emphasize the urgency of research, development and implementation of new vector control technologies that are applicable at regional and local levels. The successful application of the sterile insect technique (SIT) for the control of the New World screwworm Cochliomyia hominivorax and several species of fruit flies has given impetus to the use of this method for suppression or elimination of malaria vectors in some areas of Africa including Northern State of Sudan. The research and development phase of the Northern State feasibility study has been started. Sudanese stakeholders are working side-by-side with the International Atomic Energy Agency in the activities of this important phase. Several ethical, legal and social issues associated with this approach arose during this phase of the project. They need to be seriously considered and handled with care. In this paper, these issues are described, and the current and proposed activities to overcome potential hurdles to ensure success of the project are listed.
Field site selection: getting it right first time around
25817C. A. Malcolm, B. El Sayed, A. Babiker, R. Girod, D. Fontenille, B. G. J. Knols, A. H. Nugud and M. Q. Benedict, Malaria Journal, 8. 2009-11-16 09:57:52.
The selection of suitable field sites for integrated control of Anopheles mosquitoes using the sterile insect technique (SIT) requires consideration of the full gamut of factors facing most proposed control strategies, but four criteria identify an ideal site: 1) a single malaria vector, 2) an unstructured, relatively low density target population, 3) isolation of the target population and 4) actual or potential malaria incidence. Such a site can exist in a diverse range of situations or can be created. Two contrasting SIT field sites are examined here: the desert-flanked Dongola Reach of the Nile River in Northern State, Sudan, where malaria is endemic, and the island of La Reunion, where autochthonous malaria is rare but risk is persistent. The single malaria-transmitting vector at both sites is Anopheles arabiensis. In Sudan, the target area is a narrow 500 km corridor stretching from the rocky terrain at the Fourth Cataract - just above the new Merowe Dam, to the northernmost edge of the species range, close to Egypt. Vector distribution and temporal changes in density depend on the Nile level, ambient temperature and human activities. On La Reunion, the An. arabiensis population is coastal, limited and divided into three areas by altitude and exposure to the trade winds on the east coast. Mosquito vectors for other diseases are an issue at both sites, but of primary importance on La Reunion due to the recent chikungunya epidemic. The similarities and differences between these two sites in terms of suitability are discussed in the context of area-wide integrated vector management incorporating the SIT.
Spatial and temporal distribution of the malaria mosquito Anopheles arabiensis in northern Sudan: influence of environmental factors and implications for vector control
25826T. B. Ageep, J. Cox, M. M. Hassan, B. G. J. Knols, M. Q. Benedict, C. A. Malcolm, A. Babiker and B. B. El Sayed, Malaria Journal, 8:14. 2009-06-09 10:20:40.
Background: Malaria is an important public health problem in northern Sudan, but little is known about the dynamics of its transmission. Given the characteristic low densities of Anopheles arabiensis and the difficult terrain in this area, future vector control strategies are likely to be based on area-wide integrated pest management (AW-IPM) that may include the sterile insect technique ( SIT). To support the planning and implementation of future AW-IPM activities, larval surveys were carried out to provide key data on spatial and seasonal dynamics of local vector populations. Methods: Monthly cross-sectional larval surveys were carried out between March 2005 and May 2007 in two localities (Dongola and Merowe) adjacent to the river Nile. A stratified random sampling strategy based on the use of Remote Sensing (RS), Geographical Information Systems (GIS) and the Global Positioning System (GPS) was used to select survey locations. Breeding sites were mapped using GPS and data on larval density and breeding site characteristics were recorded using handheld computers. Bivariate and multivariate logistic regression models were used to identify breeding site characteristics associated with increased risk of presence of larvae. Seasonal patterns in the proportion of breeding sites positive for larvae were compared visually to contemporaneous data on climate and river height. Results: Of a total of 3,349 aquatic habitats sampled, 321 (9.6%) contained An. arabiensis larvae. The frequency with which larvae were found varied markedly by habitat type. Although most positive sites were associated with temporary standing water around the margins of the main Nile channel, larvae were also found at brickworks and in areas of leaking pipes and canals-often far from the river. Close to the Nile channel, a distinct seasonal pattern in larval populations was evident and appeared to be linked to the rise and fall of the river level. These patterns were not evident in vector populations breeding in artificial water sources away from the river. Conclusion: The GIS-based survey strategy developed in this study provides key data on the population dynamics of An. arabiensis in Northern State. Quantitative estimates of the contributions of various habitat types and their proximity to settlements provide a basis for planning a strategy for reducing malaria risk by elimination of the vector population.
Towards a sterile insect technique field release of Anopheles arabiensis mosquitoes in Sudan: Irradiation, transportation, and field cage experimentation
25755M. E. H. Helinski, M. M. Hassan, W. M. El-Motasim, C. A. Malcolm, B. G. J. Knols and B. El-Sayed, Malaria Journal, 7:10. 2008-04-25 10:09:22.
Background: The work described in this article forms part of a study to suppress a population of the malaria vector Anopheles arabiensis in Northern State, Sudan, with the Sterile Insect Technique. No data have previously been collected on the irradiation and transportation of anopheline mosquitoes in Africa, and the first series of attempts to do this in Sudan are reported here. In addition, experiments in a large field cage under near-natural conditions are described. Methods: Mosquitoes were irradiated in Khartoum and transported as adults by air to the field site earmarked for future releases (400 km from the laboratory). The field cage was prepared for experiments by creating resting sites with favourable conditions. The mating and survival of (irradiated) laboratory males and field-collected males was studied in the field cage, and two small-scale competition experiments were performed. Results: Minor problems were experienced with the irradiation of insects, mostly associated with the absence of a rearing facility in close proximity to the irradiation source. The small-scale transportation of adult mosquitoes to the release site resulted in minimal mortality (< 6%). Experiments in the field cage showed that mating occurred in high frequencies (i.e. an average of 60% insemination of females after one or two nights of mating), and laboratory reared males (i.e. sixty generations) were able to inseminate wild females at rates comparable to wild males. Based on wing length data, there was no size preference of males for mates. Survival of mosquitoes from the cage, based on recapture after mating, was satisfactory and approximately 60% of the insects were recaptured after one night. Only limited information on male competitiveness was obtained due to problems associated with individual egg laying of small numbers of wild females. Conclusion: It is concluded that although conditions are challenging, there are no major obstacles associated with the small-scale irradiation and transportation of insects in the current setting. The field cage is suitable for experiments and studies to test the competitiveness of irradiated males can be pursued. The scaling up of procedures to accommodate much larger numbers of insects needed for a release is the next challenge and recommendations to further implementation of this genetic control strategy are presented.
First Anopheles arabiensis germline transformation: Toward the development of a transgenic genetic sexing strain
16649H. C. Bossin, J. Thailayil, F. Catteruccia, J. P. Benton, A. Crisanti, M. Q. Benedict, B. G. Knols and A. S. Robinson, American Journal of Tropical Medicine and Hygiene, 75:66-66. 2006-11-01 20:17:39.
The ability to genetically engineer mosquitoes is likely to have major implications for the development and implementation of genetic control systems against mosquito disease vectors such as the Sterile Insect Technique (SIT). In particular, genetically transformed mosquito strains can be created for genetic marking and sexing, two key factors known to influence the effectiveness of SIT programmes. In addition, the removal of biting females before releasing sterile males in the field will be of critical importance as they contribute to disease transmission and reduce the efficiency of the release campaign. Parallel to the creation of a conventional genetic sexing strain (Y-translocation of a resistance marker), our group is undertaking a transgenic approach to the development of an A. arabiensis genetic sexing strain (GSS). The sex separation strategy under investigation relies on the sex-specific properties of the A. gambiae B2tubulin gene regulatory regions. It is hoped this approach will achieve the high sex separation efficiency (above 99%) and strain stability required for safe and efficient male-only SIT releases. We report here the successful development of transgenic A. arabiensis lines using the pPB[DsRed]B2EGFP construct. Wild-type A. arabiensis embryos were injected with a mixture of pPB[DsRed]B2EGFP and helper plasmid phsppBac (700 and 300 ng/µI respectively) following an appropriate protocol. Injections generated several transgenic sexing lines. The effectiveness of the transgenic-based sex-separation procedure, the stability of transgenic mosquito GSS under various (mass-)rearing regimes, as well as the viability and reproductive competitiveness of transgenic sterile males are being assessed.
The Sterile Insect Technique: can established technology beat malaria?
25843M. E. H. Helinski, B. El-Sayed and B. G. J. Knols, Entomologische Berichten, 66:13-20. 2006-06-06 14:48:37.
The Sterile Insect Technique (SIT) is the mass production, sterilisation and subsequent release of sterile insects into a target population in an area-wide integrated approach. The released sterile males mate with wild females; they thus no longer produce offspring and therefore the size of the target population is reduced. Over the years, SIT has proven to be a safe, effective and environmentally sound method to suppress, eliminate or contain pest populations. The International Atomic Energy Agency (IAEA) has a long history of supporting SIT programmes against key insect pests, including fruit flies, tsetse flies and moths. Recently, an integrated five year study to assess the feasibility of SIT to control African malaria mosquitoes has been initiated. In this article, we discuss the components and research requirements for such a feasibility study including sexing, mass production, sterilisation and release methodologies.
Radiation-induced sterility for pupal and adult stages of the malaria mosquito Anopheles arabiensis
25750M. E. H. Helinski, A. G. Parker and B. G. J. Knols, Malaria Journal, 5:10. 2006-05-16 15:23:31.
The optimal dose for male insects to be released in an SIT programme depends on their level of sterility and competitiveness. The use of semi-sterilizing doses to produce more competitive insects is discussed. The most convenient developmental stage for mosquito irradiation on a mass-scale are pupae, but pupal irradiation resulted in a lower insemination rate at the highest dose compared to adult irradiation. On the basis of this study, a suitable dose range that includes semi-sterilizing doses is identified to initiate competitiveness experiments for males irradiated at both developmental stages.
Genetic strategies for controlling mosquito-borne diseases
6191F. Gould, K. Magori and Y. Huang, American Scientist, 94:238. 2006-05-03 19:19:14.
Malaria kills more than a million people each year, primarily children under the age of six. Dengue fever is less deadly, but an outbreak can debilitate millions of people and easily overwhelm doctors and hospitals in tropical cities
An Anopheles transgenic sexing strain for vector control
16647F. Catteruccia, J. P. Benton and A. Crisanti, Nature Biotechnology, 23:1414-1417. 2005-10-09 20:04:20.
Here we report on the development of transgenic sexing lines for the mosquito Anopheles stephensi, the principal vector of human malaria in Asia. Male mosquitoes, expressing enhanced green fluorescent protein (EGFP) under the control of the beta 2-tubulin promoter, are identified by their fluorescent gonads in as early as their 3(rd) instar larval stage, and can be efficiently separated from females using both manual methods and automated sorting machines. Importantly, beta 2-EGFP males are not impaired in their mating ability and viable fluorescent spermatozoa are also detected in spermathecae of wild-type females mated with transgenic males. The transgenic mosquito lines described here combine most of the features desired and required for a safe application of transgenic methodologies to malariacontrol programs.
History of the Sterile Insect Technique
6360Klassen, W. and C. F. Curtis, Sterile Insect Technique: Principles and Practice in Area-Wide Integrated Pest Managemen, 2005:3-36.. 2005-03-09 20:56:59.
During the 1930s and 1940s the idea of releasing insects of pest species to introduce sterility (sterile insect technique or SIT) into wild populations, and thus control them, was independently conceived in three extremely diverse intellectual environments. The key researchers were A. S. Serebrovskii at Moscow State University, F. L. Vanderplank at a tsetse field research station in rural Tanganyika (now Tanzania), and E. F. Knipling of the United States Department of Agriculture. Serebrovskii’s work on chromosomal translocations for pest population suppression could not succeed in the catastrophic conditions in the USSR during World War II, after which he died. Vanderplank used hybrid sterility to suppress a tsetse population in a large field experiment, but lacked the resources to develop this method further. Knipling and his team exploited H. J. Muller’s discovery that ionizing radiation can induce dominant lethal mutations, and after World War II this approach was applied on an area-wide basis to eradicate the New World screwworm Cochliomyia hominivorax (Coquerel) in the USA, Mexico, and Central America. Since then very effective programmes integrating the SIT have been mounted against tropical fruit flies, some species of tsetse flies Glossina spp., the pink bollworm Pectinophora gossypiella (Saunders), and the codling moth Cydia pomonella (L.). In non-isolated onion fields in the Netherlands, the onion maggot Delia antiqua (Meigen) has since 1981 been suppressed by the SIT. In the 1970s there was much research conducted on mosquito SIT, which then went into “eclipse”, but now appears to be reviving. Development of the SIT for use against the boll weevil Anthonomus grandis grandis Boheman and the gypsy moth Lymantria dispar (L.) has ended, but it is in progress for two sweetpotato weevil species, Cylas formicarius (F.) and Euscepes postfasciatus (Fairmaire), the false codling moth Cryptophlebia leucotreta (Meyrick), the carob moth Ectomyelois ceratoniae (Zeller), the cactus moth Cactoblastis cactorum (Berg), the Old World screwworm Chrysomya bezziana (Villeneuve), additional Glossina spp., other Anastrepha spp. and Bactrocera spp. fruit flies, and other pest insects.
Malaria Control with Genetically Manipulated Insect Vectors
16035L. Alphey, C. B. Beard, P. Billingsley, M. Coetzee, A. Crisanti, C. Curtis, P. Eggleston, C. Godfray, J. Hemingway, M. Jacobs-Lorena, A. A. James, F. C. Kafatos, L. G. Mukwaya, M. Paton, J. R. Powell, W. Schneider, T. W. Scott, B. Sina, R. Sinden, S. Sink, Science, 298:119. 2002-10-04 19:49:32.
At a recent workshop, experts discussed the benefits, risks, and research priorities associated with using genetically manipulated insects in the control of vector-borne diseases.
Success in Zanzibar: Eradication of tsetse
27123A. R. Msangi, N. Kiwia, I. I. Malele, F. Mramba, K. M. Saleh, W. A. Mussa, K. G. Juma, V. A. Dyck, M. J. B. Vreysen, A. G. Parker, U. Feldmann, Z. R. Zhu and H. Pan, Area-Wide Control of Fruit Flies and Other Insect Pests, 2000-06-06 13:17:29.
There are about 22 species of tsetse flies found nowhere else in the world except in 36 countries of sub-Saharan Africa Tsetse flies transmit a debilitating and often fatal disease, trypanosomosis, which causes tremendous losses of livestock, and severely limits agricultural production (it reduces output of milk and meat, causes mortality, infertility and abortion in livestock, deprives the rural population of draught power and manure to improve and increase crop production) Tsetse flies also transmit human trypanosomosis, commonly known as 'sleeping sickness' It is estimated that over 55 million people living in rural sub-Saharan Africa are at risk from this fatal disease Tanzania's Zanzibar Island is situated 35 km off the eastern coast and comprises two main islands, Unguja and Pemba Previous surveys revealed that out of the seven tsetse species found on mainland Tanzania, only Glossina austeni Newstead infested Unguja Island No tsetse fly was found on the island of Pemba The fly is responsible for the cyclical transmission of trypanosomosis in livestock, the causative agents being mainly Trypanosoma congolense and, to a lesser extent, T vivax It is estimated that in Zanzibar, the disease causes annual losses of US$2 million Since fly suppression by conventional techniques has often resulted in short-term success, Tanzania has always appreciated that the long-term solution to the trypanosomosis problem is the eradication of tsetse flies in the country In 1994, the International Atomic Energy Agency (IAEA) and the United Republic of Tanzania embarked on a project with the objective of eradicating tsetse flies from Zanzibar Island by applying the sterile insect technique (SIT) (Dyck et al 1995, in press) Previous tsetse eradication efforts in Tanzania using SIT, enabled the establishment of a modest capacity on tsetse mass rearing in Tanga (Williamson et al 1983) The Zanzibar tsetse project was successfully completed in 1997 The estimated cost was US$7,941,000 but only US$5,788,097 was actually spent Financial assistance came from international donors such as the governments of Belgium, Canada, China, Sweden, the UK and the USA The results and achievements of the Zanzibar tsetse fly eradication project are presented in this paper
Eradication of the screwworm from Libya using the sterile insect technique
25558M. Vargas-Terán, B. S. Hursey and E. P. Cunningham, Parasitology Today, 10:119-122. 1994-01-01 09:06:27.
The introduction in 1988 of the New World screwworrn into Libya presented a serious threat to the livestock and wildlife sectors of the African continent Mediterranean and the region. In this article, MoisPs Vargas-Terin, Brian 8. Hursey and Edward P. Cunningham describe the action taken to determine the extent of the problem, to prevent the spread of the infestation and to eradicate the fly from the region using the sterile insect technique. New World screwworm hominivorax; myiasis is caused by the larval stage of the fly (Cochliomyia Coquerel) infesting the tissues of living animals. It is an obligate parasite and the female may oviposit in any wound or abrasion in mammals, including humans. Its natural distribution extends from the state of Minnesota, USA, southwards as far as Buenos Aires, A.rgentina, and includes the Caribbean region.
The New World Screwworm Eradication Programme. North Africa 1988-1992
25556Food and Agriculture Organization, FAO, 1992-06-01 08:59:36.
This book documents a programme which was unusual in several respects. The campaign to eradicate the New World screwworm from North Africa was unusually large in financial terms. At the same time it was unusually short. Era dica tion itself took about six months, although it was preceded by one year of preparation and followed by one year of continued surveillance and preventive actions. It involved an unusually large array of partners: 22 donors, eight countries at immediate risk, four UN agencies and several contractors from the private sector. What have been the main factors contributing to the success of the programme?
Tsetse fly eradication in Burkina Faso and evaluation of traps and targets
26174M. Clair, D. Cuisance, H. Politzar, P. Merot and B. Bauer, STERILE INSECT TECHNIQUE FOR TSETSE CONTROL AND ERADICATION, 1990-05-01 14:50:02.
Control operations against tsetse flies with the sterile insect technique (SIT) were conducted by the Centre de recherches sur les trypanosomoses animales (CRTA) (Institut d’élevage et de médecine vétérinaire des pays tropicaux/Gesellschaft fur Technische Zusammenarbeit (IEMVT/GTZ) Project), Bobo-Dioulasso (Burkina Faso). The project ended in 1984 with the eradication in the Sideradougou pastoral zone ofthe three tsetse species present there (Glossina palpalis gambiensis, G. tachinoides and G. morsitans submorsitans). Since 1985, besides monitoring of this area, the CRTA oriented its activities towards improving trapping by carrying out research on the form and colour of targets as well as the use of olfactory attractants.
The eradication of Glossina-palpalis-palpalis (Robineau-Desvoidy) (diptera, Glossinidae) using traps, insecticide-impregnated targets and the sterile insect technique in central Nigeria
26155W. Takken, M. A. Oladunmade, L. Dengwat, H. U. Feldmann, J. A. Onah, S. O. Tenabe and H. J. Hamann, Bulletin of Entomological Research, 76:275-286. 1986-06-01 13:33:24.
The integrated use of biconical traps, insecticide-impregnated targets and the sterile insect technique was developed for the eradication of Glossina palpalis palpalis (Robineau-Desvoidy) in a 1500-km2 area of central Nigeria. Six weeks or more of continuous removal trapping, using biconical traps, reduced the target tsetse population by more than 90% but failed to eradicate it. Males sterilized by irradiation from a ^Co source that were then released weekly induced significant sterility in target females and were successful in helping to eradicate the target population. A minimum ratio of 10:1 of sterile to wild males was required to achieve eradication in a central area of 300 km2. In marginal habitats, insecticide-impregnated targets were found adequate to control the tsetse population. The targets were also efficient as barriers to prevent reinvasion of the area. The combined effect of removal trapping and sterile male release is expected to eradicate G. p. palpalis from the entire study area.
Integration of insect sterility and insecticides for control of Glossina morsitans morsitans Westwood (Diptera: Glossinidae) in Tanzania. IV. Application of endosulfan as an aerosol prior to release of sterile males
26520D. L. Williamson, D. A. Dame, C. W. Lee, D. B. Gates and P. E. Cobb, Bulletin of Entomological Research, 73:383-389. 1983-07-07 13:20:11.
As part of a programme to test the sterile insect technique against Glossina morsitans morsitans Westw. in Tanzania, two aerial applications of endosulfan were applied to a 195-km2 test area. The applications were made with a 28-day interval to provide an initial reduction in the target species prior to the release of sterile males. A Cessna 310 aircraft equipped with a rotary atomiser and operating at night was used to apply the insecticide at a dosage of about 20 g/ha. Flyround surveys within 48 h following the spraying operations indicated that a 100% reduction of G. m. morsitans adults was achieved in both applications, while G. pallidipes Aust. was reduced by 91 5% in the first and 100% in the second.
Control of tsetse flies, Glossina spp.
26683D. A. Dame and A. M. Jordan, Advances in Veterinary Science and Comparative Medicine, 25:101-119. 1981-07-18 13:09:37.
Studies of SIT in Zimbabwe with releases of chemosterilized G. m. morsitans (Dame and Schmidt, 1970) demonstrated the feasibility of the methodology used both in the laboratory and in the field. Subsequent trials were recently completed in Tanzania, where laboratory bred sterile males were released into the natural breeding areas of a population of flies that had been partially suppressed by two aerial applications of endosulfan. Over a quarter of a million irradiated insects were released to control the G. m. morsitans population on a 195-km2 cattle ranch. The flies proved to be fully competitive andeffective. If it had been possible to isolate the plot from immigrating tsetse, the natural population on the ranch would probably have beep eliminated with a substantially lower number of flies than was necV essary to maintain the prolonged 90% level of control that was achieved (Dame et al., 1980). In Upper Volta, similar advances werd made with sterile G. p. gambiensis, bred in the laboratory and released in linear riverine habitats. Glossina p. gambiensis was eradicated from an 11-km section of the experimental plot (Cuisance et al., 1980)/ These accomplishments were completed after extensive study in Chad/ the Central African Republic, and Upper Volta.
Sterility introduced by release of genetically altered males to a domestic population of Aedes aegypti at the Kenya coast
25875P. T. McDonald, W. Hausermann and N. Lorimer, Am J Trop Med Hyg, 26:553-61. 1977-05-06 07:09:31.
The release of males heterozygous for one or two sex-linked translocations was effective in introducing a high level of sterility into a domestic population of Aedes aegypti at a Rabai village. The effect of the releases continued for several weeks after the release period. Male mosquitoes, Aedes aegypti, were released at the Kenya coast to test the effectiveness of laboratory engineered mosquitoes in introducing a genetic mechanism and the ability of the mechanism to establish itself under field conditions. A triplicate of Rabai villages was selected for the experiment. In the 1st village nottreatment was made. In the 2nd village the domestic water containers were cleaned twice a week to remove larvae and pupae. Translocation males were released in the 3rd village. A mixture of 2 types of males was introduced: the single heteroxygote male selected from 78 translocations induced by irradiation in the African strains, and the double heterozygote male. Genetic analysis of the content of release samples determined quality control of released males. Fertility was also determined with females of a strain collected at Chibarani before releases began. Hatchability of eggs in all villages was counted to assay sterility in all villages. Before the releases population fluctuations in the 3 villages were monitored for 20 weeks. The release mixture had a fertility of 37% and the single heterozygote of 50%. A daily survival rate of .63 was shown for the dusted release males. There was close agreement between the monitoring for sterility for both the egg collections and the oviposition of the LB catch females. The sterility introduced into the Chibarani population was extensive.
Lâchers de mâles stériles de Glossina tachinoides West. dans un gîte naturel de faible densité Bas-Logone, Cameroun
26657D. Cuisance and J. Itard, Revue d’élevage et de médecine vétérinaire des pays tropicaux, 26:405-422. 1973-04-01 06:33:32.
Des mâles adultes de G. tachinoides, élevés à Maisons-Alfort et irradiés entre 7 600 et 10 650 rads à Saclay (France), ont été expédiés chaque semaine par avion à N'Djamena (Tchad) entre février et juin 1973, pour être, après marquage, lâchés en plusieurs points d'un gîte naturel, sur les berges du Logone. Par suite d'une sécheresse exceptionnelle, la population de mouches sauvages dans ce gîte étant de faible densité, la proportion de mâles stériles lâchés a pu être élevée, le rapport mâles stériles/mâles sauvages étant, en moyenne, pendant toute la période des lâchers, de 2,8/I. La longévité moyenne des mâles stériles a été de 6,5 jours contre 8 jours pour les mâles sauvages. Les mâles stériles ont eu un comportement identique à celui des mâles sauvages. Bien qu'un autre gîte, qui servait de témoin, ait été fortement dégradé par l'homme et les animaux, ce qui n'a pas permis d'apprécier exactement l'effet des lâchers de mâles stériles dans le gîte d'expérience, on estime cependant qu'à partir de la mi-mars, la chute de densité de la population sauvage est en grande partie due à la présence des mâles stériles, ce qui semble confirmé par l'observation de femelles sauvages capturées dans les deux gîtes: 69 p. 100 des femelles capturées dans le gîte d'expérience n'ont eu aucune descendance au cours de trois semaines d'observation, alors que toutes les femelles du gîte témoin ont produit une pupe dans les huit jours suivant leur capture
Comportement de mâles stériles de Glossina tachinoides West. lâchés dans les conditions naturelles – environs de Fort-Lamy (Tchad). I. Transport, lâchers, rythme d’activité, action sur la population sauvage
26645D. Cuisance and J. Itard, Revue d'élevage et de médecine vétérinaire des pays tropicaux, 26:55-76. 1973-01-01 15:42:14.
Glossina tachinoides adult males, bred and irradiated with 15,500 rads in Maisons-Alfort (France) were dispatched by air-mail to Fort-Lamy (Chad) between February and May of 1972, in order to be released, after marking, in a natural area of Cameroon side of the Chari river. In this first part, the authors analyse the consequences of breeding-irradiation-transport-handling ” factors on sterile males behaviour and activity rhythm. The too small a quantity of sterile males is essentially the cause of the absence of any measurable effect on naturel population evolution.
The Sterile-Male Technique Against Tsetse Flies, Glossina Spp
26213D. A. Dame and C. H. Schmidt, 16, 24-30. 1970-03-16 15:05:33.
Simpson (1958) discussed the relationship between the biological characteristics of the genus Glossina and the use of the sterile-male technique in the control of this vector of trypanosomiasis, as did Knipling in an informal report in 1963 on Practical Role of the Sterility Principle for Tsetse Fly Eradication in WHO/Vector Control/27. Knipling estimated that an initial overflooding ratio of sterile to wild males of 3: 1 with successively smaller releases could eradicate a low-density population of flies in 12 months (Table 1) at a cost of about 125/mile2, even if the sterilized males cost as much as 5 cents each. With larger populations, other methods would have to be used to reduce the density before the releases of sterile males. Also, Knipling (1964) emphasized the economic advantage that would be gained by reduction in the total number of sterile males required if their release were preceded by a single application of a nonpersistent insecticide which would eliminate most of the adult population. When populations cover a wide area, simultaneous treatment of the entire infested area might not be feasible. A more realistic approach (Table 2) could be to systemically expand small control areas along a common front (Dame 1968).
Applications of genetic technology to mosquito rearing
6098G. B. Craig, Bulletin of the World Health Organization, 29:89-97. 1963-01-02 16:40:36.
Since the development of insecticide-resistance and the consequent partial failure of the chemical approach to the control of disease vectors, interest in the biological approach has re-awakened. An aspect of the latter approach that is of great current interest is " autocidal control "-that is, the use of insects for their own destruction. This paper discusses the various ways in which genetic mechanisms can be used to bring about the destruction of harmful insects, with special reference to those of medical importance. The author considers that the prospects for the genetic control of vector species are good, but stresses that before genetic methods can be applied on a field scale certain requirements must be met. For example, genetic technology must be expanded, a firm background of genetic knowledge of vector species must be built up, a great deal more information about vector ecology, particularly population dynamics, must be acquired, and techniques for the mass production of vector insects under controlled conditions must be developed.
On the role of lethal mutants in the control of populations
6101R. C. Von Borstel and A. A. Buzzati-Traverso, Radioisotopes and Radiation in Entomology: Proceedings of a Symposium, Bombay, 5-9 December, 1960, 1962:273-278. 1962-01-02 16:52:59.
On the role of lethal. mutants in the control of populations. Population control by release of irradiated males requires that the sperm must be damaged by radiation. The type of damage induced by radiation imposes a restriction on which species may be controlled because if the sperm are functionally damaged by radiation, then for effective control, the females must be monogamous. If dominant lethality is induced in sperm then either polygamy or monogamy may prevail. It is generally accepted that dominant lethal events are induced in sperm at doses much lower than those required to hamper sperm function or cause sperm inactivation. With Drosophila it is possible to test directly the effect of releasing irradiated males into an artificial population where polygamy is the rule. Preliminary experiments have been performed under conditions of unlimited production of offspring. It appears that radiation induces dominant lethality in sperm, and the sperm that bear dominant lethals are able to compete successfully with normal sperm. A series of tests are currently under way to ascertain the degree of induced dominant lethality and sperm inactivation at different X-ray dosages. A series of experiments are outlined in a general discussion of the possible use of dominant and recessive lethals for bringing about collapse of artificial and natural populations.
Screw-worm control through release of sterilized flies
6107A. H. Baumhover, A. J. Graham, B. A. Bitter, D. E. Hopkins, W. D. New, F. H. Dudley and R. C. Bushland, Journal of Economic Entomology, 48:462-466. 1955-08-03 17:00:44.
Screw-worms, Callitroga hominivorax (Cqrl.), did not exist in the southeastern United States until about 20 years ago, and it is probable that, if the present infestation could be eradicated, the area might be kept free of infestation through inspection of livestock shipments originating in infested areas
Possibilities of Insect Control or Eradication Through the Use of Sexually Sterile Males
6006E. F. Knipling, Journal of Economic Entomology, 48:459-462. 1955-08-01 19:58:21.
The purpose of this paper is to consider the possibility of controlling insects by releasing sexually sterile males among the existing natural population. The principles involved will be described and the potentialities as well as the limitations of the method as we know them at present, will be discussed.
Eradication of screw-worms through release of sterilized males
6091R. C. Bushland, A. W. Lindquist and E. F. Knipling, Science, 122:287-288. 1955-01-02 14:50:36.
Although the sterilizing effect of ionizing radiations has been known for years, it is only recently that entomologists have attempted to take advantage of the phenomenon for insect control. Knipling (1) has theorized on the effects of releasing sterilized males among a normal insect population. In 1947, on a visit to the Kerrville, Tex., laboratory, he proposed investigations on the mating habits of the screw-worm, Callitroga hominivorax (Cqrl.), and experiments with sterilized males. In such experiments Bushland and Hopkins (2) found that screw-worms were easily sterilized by exposing pupae to x-rays or gamma rays. They showed that under laboratory conditions male screw-worms mated repeatedly but fe males only once. If a female mated with a sterilized male it did not mate again and laid eggs that did not hatch. When mixed populations of normal and sterilized insects were observed in cages, the sterilized and normal males competed about equally for mates.
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