246 - Preparation for targeted sterile insect technique to control invasive mosquitoes in California: mosquito colonization, gender emergence ratio and separating the males

Abstract: The urban-adapted, daytime-biting Aedes aegypti is the primary mosquito vector of dengue and has the potential to transmit several other arboviruses, including Zika, chikungunya, and yellow fever. In California, Ae aegypti has spread in over 300 cities within 22 central and southern counties in less than a decade. Due to its cryptic breeding habitats, control efforts have not been successful so far. Therefore, there is a critical call for innovative biological tools such as Sterile Insect Technique (SIT) to effectively control invasive mosquitoes by expanding the existing integrated pest management (IPM). Here, we provide a summary of laboratory experiments conducted to establish Ae. aegypti colony and examine gender emergence ratios and strategies to separate males for SIT. The use of pressure operated flasks with added yeast yielded an over 80% egg-hatching success in 1.5 hr while hatching without yeast resulted below 50% hatching success. Pupae were monitored for adult emergence in plastic, and males were manually separated immediately after emergence. Among freshly emerged adults, the proportion of males was highest in the first 24 hrs (78%) and dropped to 13% on Day 6. Implications of these findings and future research ideas are discussed.