Cold survival in aphids: linking species-specific metabolic responses to cold tolerance

Aphids, as chill-susceptible insects, rely on their ability to maintain physiological homeostasis to tolerate low temperature. Interspecific variations in cold tolerance may reflect differences in physiological cold adaptation such as the ability to maintain metabolic homeostasis or accumulate cryoprotectants. To investigate this, we conducted a comparative metabolomic analysis of three aphid species (Metopolophium dirhodum, Sitobion avenae, and Rhopalosiphum padi) exhibiting distinct cold tolerance levels, using quantitative targeted GC-MS. Each species was exposed to cold at -5 °C for durations corresponding to its respective half and full median lethal times (Lt₅₀), as well as for fixed exposure time. Results revealed significant cold-induced disturbances in the metabotypes of the aphids, with more severe perturbations following the longest stress exposures. The two cold-tolerant species, M. dirhodum and S. avenae, showed similar metabolite responses during stress and increased cryoprotectants such as trehalose, proline, and asparagine after recovery. In contrast, the cold-susceptible species, R. padi, exhibited broader metabolic disruptions, especially in energy metabolism-related metabolites. These results suggest that cold tolerance in aphids is associated with dynamic metabolic restructuring, in which recovery coexists with persistent post-stress adjustments. This study enhances our understanding of the physiological basis of interspecific variations in cold tolerance and highlights specific metabolites associated with survival under cold stress.