Building better males: Improving sterile male performance in sterile insect technique programs for control of Aedes aegypti

The yellow fever mosquito, Aedes aegypti, vectors several pathogens responsible for human diseases. 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. However, questions about sterile male performance persist. We first determined the extent to which hypoxia exposure effects sterile male longevity, activity, and mating competitiveness. One hour of hypoxia was found to improve the mating competiveness of sterile males compared to males sterilized in normoxia, despite requiring a higher dose of radiation to achieve sterility. Next, we worked with a mosquito control district to develop methods for sterilizing adult Ae. aegypti to modify an existing sterile male production chain. The impacts of chilling, compaction, and radiation on survival were all assessed before combining the three into a complete adult irradiation protocol. Males chilled up to 16 hours prior to compaction and compacted to 100 males/cm³ during radiation resulted in low mortality and morbidity. Males irradiated as adults had increased longevity and similar sterility compared to males irradiated as pupae.