Impact of long-term cadmium exposure on insecticidal cross-resistance and biological traits of Brown planthopper Nilaparvata lugens (Hemiptera: Delphacidae)

Cadmium (Cd) pollution threatens ecosystems and agricultural productivity, especially in rice-growing regions. This study examines the effects of long-term Cd exposure on the brown planthopper (Nilaparvata lugens), a major rice pest, focusing on biological traits, physiological responses, and Insecticide cross-resistance. Cd bioaccumulation occurred across the soil-plant-insect chain, with higher concentrations in advanced N. lugens stages. Cd exposure prolonged development, reduced fecundity, and altered life table parameters, impairing population fitness. Physiological analyses showed increased activities of antioxidant (SOD, CAT, POD) and detoxification Enzymes (GST and P450) and neurotransmission-regulating enzyme AChE in Cd-exposed insects, indicating adaptive stress responses. Prolonged Cd exposure also induced cross-resistance to insecticides like triflumezopyrim, dinotefuran, and sulfoxaflor, evidenced by higher LC₅₀ values. Energy reserves, including glycogen, triglycerides, and total Cholesterol, were significantly reduced in Cd-exposed N. lugens, further affecting reproduction. These findings reveal the complex link between heavy metal stress and Insecticide resistance, highlighting challenges for pest management in Cd-contaminated areas. The study emphasizes the need for integrated pest management and soil remediation to mitigate heavy metal pollution's ecological and agricultural impacts. Future research should explore molecular mechanisms of Cd-induced cross-resistance and their implications for sustainable agriculture.

Bioaccumulation; Cross-resistance; Heavy metals; Insecticide resistance; Pest management.