Developing the radiation-based sterile insect technique (SIT) for controlling Aedes aegypti: identification of a sterilizing dose.

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 has 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 as a result of errors in sex sorting also are sterile and less likely to blood-feed than unirradiated females at our 50 Gy dose. © 2022 Society of Chemical Industry.