Evaluation of biological quality and reproductive competitiveness of gamma-irradiated Aedes aegypti for sterile insect technique purposes.

The sterile insect technique (SIT) has emerged as a promising and environmentally friendly strategy for the suppression of vector mosquito populations, particularly Aedes albopictus and Aedes aegypti, in different countries over the past fifteen years. However, the effectiveness of SIT largely depends on the biological quality and mating competitiveness of the sterilized males. In this context, the present study aimed to evaluate the biological and reproductive performance of males of Ae. aegypti species sterilized by gamma radiation under both laboratory and semi-field conditions. Different doses of gamma radiation (30, 40 and 50 Gy) were used to evaluate adult longevity, sterility and mating competitiveness of males irradiated at the pupal stage under laboratory and semi field conditions. The results showed that irradiation at 50 Gy was required to achieve complete sterility and that adult mosquitoes irradiated at this dose exhibited reduced longevity under competitive conditions compared with the other treatments, including the control. Competitiveness experiments demonstrated that a high proportion of irradiated males (IM) relative to non-irradiated males (10 IM:1 NIM) resulted in a substantial reduction in offspring production, although complete suppression was not achieved under these competitive conditions. These findings support the feasibility of using gamma-irradiated Ae. aegypti males for SIT-based vector control, while highlighting the need for optimized release ratios to compensate for reduced mating competitiveness.