Effects of different X-ray irradiation dosages on Wolbachia trans-infected and uninfected Aedes aegypti mosquitoes

BACKGROUND: Aedes aegypti is a primary vector of several arboviral diseases, including dengue, chikungunya, Zika, and yellow fever. Eliminating Ae. aegypti can disrupt virus transmission cycles, thereby reducing the incidence of these diseases. Releasing sterile Ae. aegypti males has been implemented to suppress their natural populations, using three approaches, i.e., ionizing radiation-induced sterilization (Sterile Insect Technique, SIT), Wolbachia-induced cytoplasmic incompatibility (Incompatible Insect Technique, IIT), and a combination of both approaches (SIT/IIT). METHODOLOGY/PRINCIPAL FINDINGS: This study investigated effects of different X-ray radiation doses on the ecological fitness of the Thai wild-type and Wolbachia trans-infected Ae. aegypti. Both wild-type and wAlbB trans-infected Ae. aegypti were irradiated with different X-ray radiation dosages, i.e., 30, 50, and 70 Gy, at the pupal stage. Our results demonstrated reduced fitness parameters in both Ae. aegypti strains when irradiation dosages increased, with greater adverse effects observed in the Wolbachia-infected group. Interestingly, 30 Gy irradiation appeared to prolong the lifespan of wAlbB trans-infected Ae. aegypti. Male fertility in both wild-type and wAlbB trans-infected mosquitoes irradiated at 50 Gy and 70 Gy was nearly zero. Wolbachia density generally declined with increasing radiation, and higher doses were associated with reduced mating competitiveness. At 30 Gy, wild-type males outperformed wAlbB trans-infected males in mating competitiveness; but it was reversed at 50 Gy and 70 Gy. CONCLUSIONS/SIGNIFICANCE: Based on the evaluation of ecological fitness parameters and mating competitiveness across various X-ray dosages under laboratory conditions, 30 Gy is recommended for sterilizing both Thai wild-type and wAlbB trans-infected Ae. aegypti. Our findings aim to improve the efficiency of sterile mosquito release programs, thereby suppressing Ae. aegypti vector populations and mitigating the risk of arboviral disease transmission.