Elevated temperature enhances aggressiveness in the swimming crab (Portunus trituberculatus): A study integrating...

Temperature critically influences crustacean behavior, yet the mechanisms underlying its effects on personality remain unclear. In this study, we quantified the aggressiveness of the swimming crab (Portunus trituberculatus) under three temperature treatments (20 °C, 25 °C, and 30 °C) and integrated physiological, transcriptomic and metabolomic analyses to investigate the underlying physiological and molecular mechanisms. Our results showed that elevated temperatures significantly increased aggressiveness while simultaneously decreasing behavioral predictability and increasing repeatability. Hemolymph glucose levels displayed a non-linear pattern characterized by higher concentrations at both 20 °C and 30 °C, whereas lactate levels followed a generally increasing trend with rising temperature. In contrast, glycogen in claw muscle remained relatively stable. Integrated transcriptomic and metabolomic analyses further revealed phase-specific regulatory mechanisms of enhanced aggressiveness. The transition from 20 °C to 25 °C was characterized by a metabolism-centered response, with significant activation of lipid and amino acid metabolism pathways. In contrast, the shift from 25 °C to 30 °C was linked to enhanced neural processes, including enrichment of pathways such as serotonergic synapse, neuroactive ligand-receptor interaction, and cAMP/MAPK signaling. This neural activation was accompanied by upregulation of glycolysis/gluconeogenesis and starch/sucrose metabolism, ensuring a rapid energy supply for intensified aggressive behavior. These results demonstrate that temperature enhances aggressiveness through coordinated energy provisioning and neural activation, providing a mechanistic understanding of crustacean behavioral responses to climate changes.