Insights into the toxicity effects of indoxacarb against Spodoptera frugiperda using metabolomics combined with mass spectrometry imaging

BACKGROUND: As one of the most destructive and invasive pests for various plants in China, Spodoptera frugiperda (Lepidoptera: Noctuidae) poses an enormous threat to food security and results in serious economic losses for harvesting and consumption of agricultural vegetables. To this end, indoxacarb has shown great promise as an effective insecticide against Spodoptera frugiperda. It is metabolized by insect esterases or amidases into the N-decarbomethoxy metabolite (DCJW), which is a key metabolite responsible for the insecticidal activity of indoxacarb. The efficiency of DCJW generation directly affects the efficacy of pest control against target species such as Spodoptera frugiperda. Despite these efforts, insights into in situ metabolic regulation of Spodoptera frugiperda toward indoxacarb remain unclear. RESULTS: Herein, we systematically explored the toxic effects of indoxacarb on Spodoptera frugiperda, including growth and development, locomotion, feeding, enzyme activity, expression levels and spatial distribution of metabolites. After indoxacarb treatment for 48 h, Spodoptera frugiperda exhibited a longer movement distance and lower food consumption with detoxifying enzymes significantly affected. Combining complementary strengths of metabolomics and mass spectrometry imaging, this study not only identifies dysregulated metabolic changes in Spodoptera frugiperda but also visualizes the spatial distribution of key metabolites and lipids. CONCLUSION: Collectively, the findings suggest that the high toxicity of indoxacarb regarding Spodoptera frugiperda may be due to the inhibition of purine and amino acid metabolism, and mitochondrial damage, providing new perspectives for deciphering the toxicity mechanism between pesticides and target organisms. © 2025 Society of Chemical Industry.