Effects of emamectin benzoate ingested by feeding on aphids on reproduction and predation of the ladybird beetle, Coccinella septempunctata
Widespread pesticide exposure has adverse ecological effects on non-target insects, threatening long-term population survival. Although natural enemy ladybird beetles (Coccinella septempunctata L) in agricultural field are indirectly exposed to insecticides by consuming insecticide-exposed aphids, the potential effect on C. septempunctata remain largely unknown. This study examined the impacts of consuming aphids (Megoura crassicauda M) treated with different concentrations (LC10 and LC50) of emamectin benzoate (EB) on the reproduction, predatory capacity, and offspring fitness of C. septempunctata. Results showed that exposure to the LC10-treated aphids caused greater reductions in survival rate, emergence rate, oviposition period, fecundity, and predation compared to the LC50 exposure in both the F0 and F1 generations. Additionally, ingestion of LC10-treated aphids significantly increase the activities of GST, CarE, and mixed-function oxidase (MFO), as well as the expressions of five detoxification-related genes (GST, Cyp6A14, HSP70, ABCA3, and ABCB1). This study suggests that indirect ingestion of aphids treated with sublethal concentrations of insecticides may pose a risk to C. septempunctata population survival. These study provide insight for optimizing insecticide application in integrated pest management (IPM) strategies to support natural enemy populations.