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Imidacloprid is a potent neonicotinoid insecticide that exerts control over cotton aphids. Binodoxys communisis the predominant parasitic threat to cotton aphids, serving as a crucial biological means to control cotton aphids. Imidacloprid has been Sprayed to control cotton aphids, but it also causes toxic effects on the natural enemies of cotton aphids, such as parasitic wasps, Binodoxys communis. However, the sublethal impact of imidacloprid on parasitic antagonists has remained unclear. This study sought to investigate the sublethal effects of imidacloprid on B. communisat the biological phenotype and transcriptional level, as well as the impact of imidacloprid on the microbial composition in the B. communis. Our research indicated that the sublethal dosages of imidacloprid imparted significant biologic adverse impacts on B. communis, including extended larval and pupal stages, as well as reduced parasitism and emergence rates. Following treatment with imidacloprid, transcriptomic analysis identified 1263 significantly differentially expressed genes. These differentially expressed genes were predominantly annotated in metabolic routes, and the annotated genes mainly belong to the fatty acid metabolism pathway, the carbon metabolism pathway, and protein processing in the endoplasmic reticulum pathway. 16S rDNA sequencing results showed significant changes in the composition of the microbial community in B. communisafter exposure to imidacloprid. A total of 14 bacteria exhibiting the highest abundance in parasitic wasps were found, and the microbiota abundance of Akkermansia, Bacteroides, Streptomyces, Helicobacter, and Prevotellaceae UCG_001was noticeably reduced, while Lactobacillus, Escherichia Shigella, Ligilactobacillus, Lachnospiraceae, Rikenellaceae RC9_gut_group, Erysipelatoclostridium, Acinetobacter, Enterococcus, and Aquabacteriumwere significantly elevated. By evaluating the enrichment pathways of microbial functions, it was found that the microbial functions with significant changes in proportion were mainly annotated to the carbon, fatty acid, and amino acid (aa) metabolic pathways, which was consistent with the transcriptome sequencing results. This finding mirrored transcriptome analysis results. According to transcriptomics analysis and 16S rDNA sequencing data, imidacloprid limits changes in metabolic pathways of B. communis, including fatty acid metabolism, impacting the development and parasitic competence of B. communis. Accordingly, the gene expression linked to detoxification and the cytochrome P450 gene family was significantly elevated at 1 h and significantly declined after three days.

Insecticides play a crucial role in safeguarding crops from pest. However, prior to their release, it is essential to assess the efficacy and potential effects of these protectants. Flupyradifurone (FBF) and sulfoxaflor (SFX), two insecticides commonly used to control aphids, have been found to exert negative effects on the growth and development of Binodoxys communisGahan,a beneficial parasitic wasp that targets aphids. However, it remains unknown if FBF and SFX influence the symbiotic bacteria residing within B. communis. In this study, 16SrRNA sequencing was utilized to assess the populations of B. communissymbionts exposed to sublethal concentrations (LC10and LC25) of FBF and SFX. The control and treatment groups exhibited similar bacterial community structures, with Bacteroidotaidentified as the dominant phylum in each. After exposure to FBF and SFX, the diversity and richness of symbionts (Firmicutes, Bacteroidota,and Actinobacteriota)in B. communischanged notably. The two different insecticides and exposure durations exerted distinct effects on the microbial community. For instance, SFX stress resulted in a decrease in Akkermansiaand an increase in Escherichia Shigella1h after exposure, with both returning to baseline levels after 3d. In contrast, FBF exposure caused a reduction in Akkermansiapresence after 1h, which persisted even after 3d. This study represents the first assessment of the effects of FBF and SFX exposure on symbiotic bacteria in B. communis, expanding our understanding of how insecticides influence natural enemies and their symbiotic bacterial relationships. This study provides theoretical guidance for field applications of FBF and SFX, as well as a reasonable basis for exploring chemical resistance conferred by symbiotic bacteria.