Parasitoid of Aphis gossypii, Binodoxys communis Gahan exhibits metabolic changes in symbiotic bacterial community upon exposure of insecticides

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 communis Gahan, 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. communis symbionts exposed to sublethal concentrations (LC₁₀ and LC₂₅) of FBF and SFX. The control and treatment groups exhibited similar bacterial community structures, with Bacteroidota identified as the dominant phylum in each. After exposure to FBF and SFX, the diversity and richness of symbionts (Firmicutes, Bacteroidota, and Actinobacteriota) in B. communis changed notably. The two different insecticides and exposure durations exerted distinct effects on the microbial community. For instance, SFX stress resulted in a decrease in Akkermansia and an increase in Escherichia Shigella 1h after exposure, with both returning to baseline levels after 3d. In contrast, FBF exposure caused a reduction in Akkermansia presence 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.