Optimization of irradiation sterility dose of the male Aedes aegypti (Linnaeus) Mosquito: a laboratory study in Bangladesh

In many ways, management of the notorious vector mosquito, Aedes aegypti is difficult by conventional mosquito control measures. Sterile Insect Technique (SIT) by using irradiation can be considered as one of the environmentally benign alternatives. As radiation is deleterious to mosquito, therefore, careful studies are needed to select an optimal irradiation dose that will ensure the quality of irradiated males for field release. Hence, in this study we have attempted to determine the appropriate radiation dose that may satisfy the fitness qualities of irradiated male mosquito, Aedes aegypti for SIT applications. This study was conducted in laboratory conditions. Radiation doses of 40, 50, 60, and 70 Gy from Co⁶⁰ irradiator were applied to 26-32 h old male pupae and subsequently, the radiation effects on pupal survivability, sterility, fertility, wing size, flight ability, adult longevity and mating competitiveness were assessed. Significant effect on sterility was observed in all the radiation doses studied which ranged between 98.97 ± 0.05 and 99.96 ± 0.02%. However, on average the sterility in the control group was found to be 28.81 ± 6.41%. This study did not observe any significant radiation effects on adult emergence, flight ability and wing size. But mean adult longevity was significantly affected by the radiation doses studied (P < 0.05). Fried index of mating competitiveness was 0.82 ± 0.05 at 60 Gy. The results of this study preliminary showed that the radiation dose of 60 Gy can be considered as the effective dose for achieving male sterility while keeping the male performances to a satisfactory level.