Temperature modulates food competition-related offensive and escape behaviors in different male fruit fly strains

Ambient temperature significantly influences behavioral strategies in ectothermic animals. Food-related aggression, as a form of social behavior, provides an ecologically relevant and experimentally tractable model for studying conflict, involving a defined and controllable resource. However, how temperature variation modulates offensive and escape behaviors during such competition, especially in model organisms like fruit flies, remains unclear. This study compared the behavioral responses of two laboratory strains of male Drosophila melanogaster ( Canton-S and w ¹¹¹⁸ ) under different temperatures during food competition. We quantified wing threats, physical contact, and withdrawal behaviors. Results showed that both offensive and escape actions were significantly reduced under cooler conditions (~ 18°C). Canton-S males displayed stronger offensive and escape behaviors than w ¹¹¹⁸ males at low temperature, indicating genotype-specific plasticity. Wing threats showed weaker strain differences, suggesting they may function as low-cost exploratory signals. In contrast, physical contact behaviors exhibited marked temperature- and genotype-dependent variation. These findings show that ambient temperature and genetic background jointly regulate competitive behavior’s in fruit flies. w ¹¹¹⁸ males may adopt a more energy-conserving strategy under cold stress. Our study highlights the role of genotype–temperature interactions in shaping adaptive strategies during resource competition.