Quality Control and Mating Performance of Irradiated Glossina palpalis gambiensis Males

SIMPLE SUMMARY: In vector control programs based on the sterile insect technique (SIT), the biological quality of sterile males must be as high as possible to compete with their wild counterparts. This study evaluates the biological quality and mating performance of sterile male Glossina palpalis gambiensis produced in a mass-rearing facility in Burkina Faso. It shows that irradiation had no effect on the adult emergence rate but reduced the percentage of operational flies and male fly survival. Irradiation had no effect on mating performances, as all females were inseminated, and the sterile males competed well with unirradiated males for virgin females in walk-in field cages. However, the sterility rate induced in females was lower than expected (89.67%). This study indicates that, under experimental field cage conditions, the G. p. gambiensis males produced at the CIRDES are well-suited for use in area-wide integrated pest management (AW-IPM) programs that have an SIT component. The reduction in the sterility rate highlights the importance of regularly monitoring the biological parameters of sterile males and the radiation source. ABSTRACT: The biological quality of sterile male insects produced in a mass-rearing facility is a prerequisite for the success of the SIT, which is a component of area-wide integrated pest management (AW-IPM). Indeed, sterile male insects released in the field must have a good mating performance in order to compete with wild males, but they must also present the required level of sterility. In the present study, the biological quality of sterile male Glossina palpalis gambiensis produced in a mass-rearing insectary was assessed through quality control testing. The mating performance of irradiated males was assessed in walk-in field cages. Irradiation had no effect on adult emergence but significantly reduced the percentage of operational flies (from 89.58% to 79.87%) and male survival (from 5 to 4 days, on average). However, irradiation did not impact the sterile male insemination potential, with all females inseminated and more than 80% of the spermathecae completely filled. The rate of induced sterility in females was 89.67% due to a dose rate decrease of the radiation source. Moreover, sterile males were able to compete successfully with untreated fertile males for untreated females in walk-in field cages. This study confirmed that the flies were still competitive and stressed the importance of regularly checking the radiation source parameters.