Cadmium exposure increases insecticide sensitivity of Sogatella furcifera (Horváth) by decrease the diversity of symbiotic bacteria

Cadmium (Cd) is a prevalent environmental pollutant in agricultural ecosystems, particularly within paddy ecosystems, is readily absorbed by rice and enter herbivorous insects through the food chain, thereby influencing the implementation of integrated pest management strategies. However, the effect and mechanisms of Cd exposure on the sensitivity of pests in paddy to insecticides remain unclear. Therefore, this study investigated the effects of Cd exposure on the fitness, insecticide sensitivity and symbiotic bacteria of Sogatella furcifera (Horváth) (white-backed planthopper, WBPH). Cd exposure did not affect the population growth of WBPH but significantly increased the sensitivity to three insecticides, nitenpyram, dinotefuran and etofenprox. Furthermore, Cd exposure reduced the diversity of symbiotic bacteria in WBPH, particularly decreasing the relative abundance of Acinetobacter, Klebsiella, Chryseobacterium and Pantoea, which were positively correlated with the survival rate of WBPH after Cd exposure and pesticide treatment. This indicates that Cd exposure may enhance insecticide sensitivity by disrupting the symbiotic bacteria equilibrium within WBPH. This study provides new insights into the symbiotic bacteria mediated increase in insecticide sensitivity due to heavy metal exposure, providing a foundation for utilizing compounds that disturb symbiotic bacteria balance in pest for pest control.