Joint FAO/IAEA Coordinated Research Project on Mosquito Handling, Transport, Release and Male Trapping Methods in Support of SIT Application to Control Mosquitoes

M. Gómez, B. J. Johnson, H. C. Bossin and R. Argilés-Herrero,  Insects,  14. 2023.

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]. (3) Additionally, the impacts of temperature, time, and compaction, and the interactions between them, were explored to improve the handling, shipping, and transportation of chilled males [11]. Based on these results, suitable protocols for short- and long-distance shipments were developed for Aedes aegypti [12,13], with likely extension to other members of the Stegomyia subgenus, including Aedes albopictus and Aedes polynesiensis. Countries such as Brazil have already implemented and evaluated developed protocols under operational conditions [13]. (4) Alongside these protocols, methods for ground and aerial releases (using drones) were developed and evaluated. Remotely piloted aircraft systems (RPASs) with embedded mosquito release devices have been developed and evaluated under laboratory and field conditions for Ae. aegypti in countries such as Mexico [14]. While there are still several challenges to be addressed before implementing this approach in SIT pilot projects against mosquitoes, results from CRP-conducted research demonstrate that drone-based aerial releases are a powerful and cost-effective alternative to traditional ground-based releases. (5) To better assist all forms of release, a novel all-in-one release container was developed to maximize release densities while maintaining male viability [15]. The developed container allows mosquitoes to be maintained in relatively undisturbed conditions from the pupal stage until release as adults, to eliminate the negative effects of post-emergence handling associated with the majority of large-scale release systems. (6) Lastly, the behavioral responses of male Ae. albopictus to different volatile compounds were studied to identify chemicals which may enhance male Ae. albopictus surveillance [16]. Decanoic acid was found to be attractive to male Ae. albopictus in moderate concentrations, whereas most other compounds were found to act as repellents. Studies such as this are critical to developing alternative surveillance strategies to assist mosquito-based SIT packages.

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