Effects of starvation and age on death-feigning behaviours of Tribolium castaneum

Investing in predation avoidance behavior by prey greatly contribute to increases its own survival rate. On the other hand, because investing in predation avoidance is synonymous with sacrificing time and resources for other behaviors, prey may plastically vary their investment in predation avoidance depending on predation risk and their condition. In this study, we investigated how hunger level and age influence the duration of death-feigning behavior, a common anti-predator tactic, in the red flour beetle ( Tribolium castaneum ). Our results demonstrated that the duration of death feigning decreased as hunger levels increased, supporting previous findings that starvation risk modulates anti-predator investment. In contrast, well-fed beetles exhibited a gradual increase in death-feigning duration over a 30-day period post-emergence. This age-related pattern has not been previously reported. Although the underlying mechanism remains unclear, one possible explanation is that increased body mass and enhanced starvation resistance over time allow for greater investment in anti-predator behavior. These findings contribute to a deeper understanding of the context-dependent plasticity of death-feigning behavior and its ecological significance.