Phoxim sublethal effect induces vitellogenin mediated reproductive enhancement and alters microbial symbiosis across generations in Hylyphantes graminicola

BACKGROUND Phoxim, a widely used organophosphate insecticide, poses potential risks to non-target natural enemies. Hylyphantes graminicola is a dominant predatory spider in agroecosystems, yet the sublethal effects and transgenerational impacts remain poorly characterized. This study aimed to systematically evaluate the physiological, molecular, and microbial changes in H. graminicola induced by low lethal concentration of phoxim exposure across two successive generations. RESULTS Laboratory bioassays determined the LC 30 of phoxim to be 9.442 mg/L. Exposure at this concentration significantly reduced female longevity but increased fecundity in both F 0 and F 1 generations, suggesting a potential hormetic effect. Transcriptomic analysis revealed that reproduction-related genes were significantly upregulated in the F 0 generation, whereas detoxification genes were markedly expressed in the F 1 generation. Functional validation through RNAi confirmed that vitellogenin ( Vg ) and cytochrome P450 ( CYP2J1 ) are crucial in reproduction and detoxification, respectively. Furthermore, acetylcholinesterase ( AChE ) was also found to be involved in regulatory phoxim exposure. Moreover, microbiome profiling demonstrated substantial shifts across generations, including decreased Wolbachia and increased Candidatus_Cardinium abundance, which may be related to the observed increase in fecundity. The results showed that a low lethal concentration of phoxim exposure can trigger complex physiological and microbial changes across generations. CONCLUSION These findings underscore the necessity of optimizing insecticide application intervals within Integrated Pest Management (IPM) frameworks to preserve biological control provided by beneficial arthropods. © 2026 Society of Chemical Industry.