Abstract / Summary
Abstract The pyrethroid insecticides like Cypermethrin is widely used against agricultural pests, but its biochemical and tissue specific sublethal effects in non-model coleopteran pests has not been yet understood. This study tried to address the acute toxicity and time dependent biochemical responses of Mupli beetle ( Luprops tristis ), a major residential pest in rubber plantations in South India, to Cypermethrin. Mortality (LD₅₀) was estimated by probit analysis, and adults were then exposed to a sublethal concentration (1/10 LD₅₀) to assess oxidative stress, digestive metabolism, and neuro-detoxification in whole body, gut, and fat body over 24–96 h. Cypermethrin exposure caused a significant, time-dependent decline in antioxidant enzymes, including superoxide dismutase, catalase, peroxidase, glutathione peroxidase, and glutathione reductase (p < 0.05), with the most visible inhibition in gut tissues, indicating severe tissue-specific oxidative imbalance. Digestive enzymes (α-amylase, protease, and lipase) also showed progressive reduction, especially in the gut, reflecting impaired nutrient assimilation and metabolic disruption. Glutathione-S-transferase (GST) activity showed marked suppression in all tissues, most strongly in the gut, demonstrating reduced detoxification capacity, while acetylcholinesterase (AChE) activity was significantly inhibited in a time- and tissue-dependent manner, confirming neurophysiological impairment under sublethal exposure. Collectively, these findings show that Cypermethrin elicits sustained oxidative stress, metabolic dysfunction, and compromised detoxification and neural function in L. tristis in a distinctly tissue-specific manner and advocate the need for multi-tissue biochemical biomarkers for sublethal assessment of pesticides in plantation ecosystems.