Assessing the impact of gamma irradiation on key biological traits of peach fruit fly, Bactrocera zonata (Diptera: Tephritidae) under laboratory conditions

Bactrocera zonata (Saunders) (Diptera: Tephritidae) poses a significant threat to global fruit production due to its high reproductive capacity and broad host range. This study aimed to evaluate the effects of gamma irradiation on key biological parameters of B. zonata. Six-day-old pupae were exposed to irradiation doses of 0, 30, 40, 50, 60, and 70 Gy, and subsequent developmental and reproductive traits were assessed to determine the impact of irradiation. Post-irradiation results revealed a dose-dependent trend. Higher doses ([≥]50 Gy) significantly reduced adult emergence, increased the incidence of partially emerged or deformed adults, and shortened adult longevity. Reproductive potential was significantly impaired in males irradiated at 60 and 70 Gy when mated with un-irradiated females, resulting in a marked decline in both fecundity and egg hatchability. Females irradiated at doses [≥]50 Gy failed to produce eggs when paired with either irradiated or non-irradiated males, indicating a high level of radio-sensitivity in female flies. Additionally, several traits in the F1 generation such as pupal recovery, pupal size, and adult development exhibited significant abnormalities and suggesting that the effects of irradiation may be transmitted to the next generation. Sterility was highest in males irradiated at 60 and 70 Gy, while females exhibited complete sterility at doses exceeding 40 Gy. The findings indicate that a dose of 70 Gy may be optimal for effective sterility induction in B. zonata. However, further detailed studies are required to standardize this dose, incorporating rigorous quality control measures to optimize its application in sterile insect technique (SIT) programs.