Untargeted metabolomics reveals divergent metabolic profiles between the predatory Arma chinensis and the Phytophagous Halyomorpha halys.

Arma chinensis (Fallou) (a predatory insect) and Halyomorpha halys (Stål) (a phytophagous insect) exhibit distinct feeding ecologies. This contrast provides a model system to investigate metabolic divergence in insects, which remains insufficiently characterized. To address this, we employed untargeted metabolomics for comparing the global metabolic profiles of these 2 species. Significant differences were detected between A. chinensis and H. halys, with 194 and 195 differentially abundant metabolites identified in females and males, respectively. The metabolic profile of A. chinensis was characterized by an enrichment of lipids and lipid-like molecules. In contrast, H. halys exhibited an enrichment of organic acids, their derivatives, and plant-derived secondary metabolites, consistent with its phytophagous diet. Sex-specific metabolic patterns were also observed: females showed higher lipid accumulation, a pattern often associated with reproductive investment in insects, whereas males displayed a relative increase in metabolites related to protein synthesis. This study elucidates the distinct metabolomic signatures associated with different feeding habits for 2 closely related insect species. These findings provide a foundation for further investigation into the physiological correlates of dietary ecology and may inform future research into pest management strategies.