Host-microbe synergy in pesticide resilience: Rhodococcus-driven fitness compensation in chlorpyrifos-stressed Binodoxys communis.

Chlorpyrifos (CPF), a widely used organophosphate insecticide in cotton cultivation for controlling Aphis gossypii, has Binodoxys communis as the primary parasitic natural enemy of A. gossypii. This study evaluated the impact of two sub-lethal CPF concentrations (LC10 and LC30) on key biological parameters across two generations, transcriptomic responses, and symbiotic bacterial communities in B. communis. CPF exposure significantly reduced F1 generation survival by 39.89 % (LC10) and F2 generation survival by 33.31 % (LC30). Emergence rates were markedly decreased in both F1 (33.43 %) and F2 (19.86 %) generations under LC10 exposure. Furthermore, LC10 treatment significantly prolonged the F1 pre-pupal stage by 31.58 %. Short-term (1 h) CPF exposure markedly suppressed the expression of genes involved in energy metabolism, lipid metabolism, and PPAR signaling pathways. Notably, CPF exposure (both 1 h and 3 days) resulted in a significant increase in the relative abundance of Rhodococcus, suggesting a potential role of this bacterium in enhancing B. communis fitness under insecticide stress. Our findings not only inform the judicious application of CPF, but also identify molecular targets associated with energy and nutrient metabolism, while laying the groundwork for harnessing bacteria to enhance pesticide resistance in parasitoid wasps.