Impact of Chilling Temperature and Its Exposure Period on Survival, Flight Ability and Sterility of Aedes aegypti (Linnaeus) (Diptera: Culicidae)

Abstract

Abstract The tiny bloodsuckers Aedes aegypti is the primary vector of some fatal diseases like dengue, zika and yellow fever which presents a significant concern for the healthcare sector of Bangladesh. To manage this insect pest, the feasibility of sterile insect technique (SIT) in Bangladesh is being investigated for which quality radio-sterilized males are indispensable. Typically, the sterile males are chilled at low temperature to facilitate their transportation from rear-out-facility to the release site, concurrently to minimize the metabolism, stress and physical damage. In this study, the impact of chilling temperatures (4, 7 and 10°C) and exposure periods (1, 4, 8 and 24h) have been studied on the survival, chill-coma recovery rate (CCRR), induced sterility and flight ability of lab-reared local A. aegypti strain. Different chilling temperatures showed insignificant effect on CCRR except the 24h exposure duration. Log-rank test of Kaplan-Meier survival curve resulted the significant effect of chilling temperature and duration on the survival. Notably, the chilling temperature of 7°C exposed for 1h was found to be optimum in terms of survival. Hence, the induced sterility and flight ability were studied only for this specific temperature and duration, revealing the insignificant effects between the sterile-chilled and sterile but non-chilled A. aegypti. This study underscores the recommendation to chill the mosquitoes at 7°C for 1h which will be helpful for the implementation of SIT in Bangladesh.