Rearing of Glossina morsitans morsitans tsetse flies for the sterile insect technique: evaluating the impact of irradiation and transportation during early and late-stage pupal development on the quality of emerging adults

Human African trypanosomiasis (HAT) and African animal trypanosomosis (AAT) are devastating diseases spread by tsetse flies (Glossina spp.), affecting humans and livestock, respectively. Current efforts to manage these diseases by eliminating the vector through the sterile insect technique (SIT) require transportation of irradiated late-stage tsetse pupae under chilling, which has been reported to reduce the biological quality of emerged flies. We therefore evaluated the impact of irradiation and transportation (including vibration and shock) on pupae at early-stage development (22 days of age) under ambient temperature and compared it to that on pupae at the late-stage development (29 days of age) under chilling, the current practice for tsetse in SIT programs. The quality of flies emerging from these transported pupae was assessed by their emergence rates, flight propensity, mating ability, insemination rates and survival rates (over ca. 100 days, and after specified shorter periods). Generally, flies emerging from the 22-day-old pupae had significantly (p