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

Authors: CHEN, CHAO - University Of Florida; Aldridge, Robert; Gibson, Seth; KLINE, JEDIDIAH - Orise Fellow; ARYAPREMA, VINDHYA - Anastasia Mosquito Control District; QUALLS, WHITNEY - Anastasia Mosquito Control District; XUE, RUI-DE - Anastasia Mosquito Control District; BOARDMAN, LEIGH - University Of Florida; Linthicum, Kenneth - Ken; HAHN, DANIEL - University Of Florida

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/24/2022
Publication Date: 12/11/2022
Citation: Chen, C., Aldridge, R.L., Gibson, S., Kline, J., Aryaprema, V., Qualls, W.A., Xue, R., Boardman, L., Linthicum, K., Hahn, D.A. 2022. Developing the radiation-based sterile insect technique (SIT) for controlling Aedes aegypti: identification of a sterilizing dose. Pest Management Science. 79(3):1175-1183. https://doi.org/10.1002/ps.7303.
DOI: https://doi.org/10.1002/ps.7303

Interpretive Summary: Aedes aegypti mosquitoes are a disease spreading mosquito that is difficult to control through traditional methods. Their behavior to live in close proximity to humans, to develop in hidden water sources, the increasing resistance to EPA approved pesticides, pesticide deregistration, and the slow production of novel pesticides further complicate control strategies. One novel method to control Ae. aegypti is the sterile insect technique (SIT) that leverages the mass release of irradiated (sterilized) males to overwhelm mate choice of females. Our goal in this study was to test the effect and dose of gamma radiation applied to Ae. aegypti mosquitoes collected from St. John's Co., Florida. An optimal dose ~50 Gy was identified, and the impact on survival and reproductive fitness were analyzed against non-irradiated (i.e., wild) male mosquitoes.

Technical Abstract: BACKGROUND: The sterile insect technique (SIT) is emerging as a tool to supplement traditional pesticide-based control of Aedes aegypti, a prominent disease-vector mosquito that has been increasing 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 used Ae. aegypti reared in colony from St. Augustine, Florida, USA, to investigate the effects of ionizing radiation (gamma) on male survival, longevity, mating behavior, and sterility in a dose-response design. This work is a first step towards developing an operational SIT field suppression program against Ae. aegypti in this location. RESULTS: Exposing late state pupae to 50 Gy of radiation yielded 99% male sterility while maintaining high survival to adult emergence, adequate longevity, and adequate 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 propensity 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 and any females that might be accidentally released with sterile males due to errors in sex sorting are both sterile and less likely to blood feed than unirradiated females.