Sublethal and lethal effects of avermectin on reproductive success, hormonal regulation, and population dynamics of the oriental fruit fly, Bactrocera dorsalis

Abstract BACKGROUND The oriental fruit fly, Bactrocera dorsalis , causes significant economic losses in fruit production because of its high reproductive rate and adaptability. The current study investigated the sublethal and lethal effects of avermectin, a macrocyclic lactone insecticide, on the F 0 and F 1 generations of B. dorsalis . RESULTS This study demonstrated that exposure to avermectin with sublethal and lethal (LC 5 , LC 20 , and LC 50 ) concentrations reduced mating rates, prolonged pre‐mating periods, and lowered levels of juvenile hormone (JH) and 20‐hydroxyecdysone (20E). Furthermore, avermectin exposure resulted in a decrease in vitellogenin ( Vg ) and vitellogenin receptor ( VgR ) levels, with downregulated expression of the corresponding genes. Subsequent investigations revealed that avermectin exposure led to reduced sugar accumulation indicated by decreased glycogen, glucose and trehalose levels, alongside impaired trehalase activities and lower triglyceride content in the F 0 generation of B. dorsalis . These metabolic disruptions contributed to decreased hatching, pupation and emergence rates, and lower pupal weights and reproductive parameters (as demonstrated by life table parameters) in the F 1 generation. Furthermore, increased activities of detoxifying enzymes such as glutathione S ‐transferase, carboxylesterase and cytochrome P450 monooxygenases were found, suggesting an adaptive response to detoxify avermectin. CONCLUTION These findings highlight the potential long‐term impacts of avermectin on B. dorsalis population dynamics and underscore the need for incorporating considerations of sublethal effects into integrated pest management strategies. © 2025 Society of Chemical Industry.