Cross-Generational Ripples: Sublethal Fipronil Exposure Alters Binodoxys communis Microbiome Without Lethal Consequences

Lisha Wang¹Liu Weijiao²Li Wang²Kaixin Zhang²Dongyang Li²Jichao Ji²Junyu Luo²Zhu Xiangzhen²Jinjie Cui²Xueke Gao^2*

• ¹Institute of Cotton Research, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
• ²Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China

Fipronil, a broad-spectrum phenylpyrazole insecticide, demonstrates high efficacy against Aphis gossypii (cotton aphid). However, its potential effects on Binodoxys communis, a key natural enemy of A. gossypii remain largely unexplored. This study comprehensively assessed the safety of fipronil for B. communis, with particular emphasis on sublethal effects and associated microbiome alterations. Our findings demonstrate that indirect fipronil exposure significantly prolonged larval development in the parental generation (F0, P= 0.017), while showing no statistically significant impact on either the offspring generation (F1) or directly exposed individuals in both parental (F0) and offspring (F1) generations. 16S rRNA sequencing analysis revealed apparent alterations in the microbial diversity and community structure of B. communis. In adults, we observed a dramatic shift in dominant genera from Akkermansia to Muribaculum following 1 h exposure, while the dominant phylum remained unchanged but showed significantly reduced abundance after 3 d. Notably, compared to adults, the microbial community changes in larvae exhibit distinct patterns: with no change in the major phylum (Proteobacteria) and a shift in the major genus from Brevitalea to Vicinamibacter. These results highlight previously unrecognized ecological risks associated with fipronil application in agriculture management systems, emphasizing the need for pesticide risk assessments that consider sublethal effects on beneficial insects and their symbiotic microbiota.