Study of Sublethal Effects of Beta-cypermethrin of Evergestis extimalis (Lepidoptera: Pyralididae)

Abstract Evergestis extimalis, a significant pest of rape plants, has developed resistance to commonly used insecticides due to prolonged and excessive chemical insecticide use. This study aimed to preliminarily explore the sublethal effects of beta-cypermethrin on E. extimalis and its detoxification mechanism at the molecular level. In the F1 generation, sublethal effects diminished, yet population biological parameters showed an upward trend, potentially contributing to the resurgence of E. extimalis. Specifically, the developmental duration of 1st instar larvae in the F1 generation was significantly extended compared to the control, while other stages and life table parameters remained largely unaffected. Under beta-cypermethrin stress, glutathione S-transferase (GSTs) activity exhibited an induction-inhibition-induction pattern, carboxylesterase (CarE) activity remained elevated for 72 hours, and cytochrome P450s (P450s) activity initially declined before increasing in the LC25 treatment group. Transcriptome analysis revealed 1501 differentially expressed genes, primarily enriched in metabolic, biosynthetic, and detoxification metabolism pathways. Among these, 14 P450s, 5 CarEs, 4 GSTs, and 2 UDP-glycosyltransferases (UGTs) were identified. Enzyme activity kits were utilized to assess detoxification enzyme responses to beta-cypermethrin, revealing significant reductions in fecundity in the F0 generation. The LC25 treatment group exhibited a significantly lower daily egg production compared to the control. The F1 generation exhibited an upward trend in life table parameters, indicating a potential stimulatory effect of beta-cypermethrin stress on reproductive capacity.