Trait-specific responses to repeated stressor exposure reveal context-dependent learning in wild crickets

Habituation allows animals to reduce their responsiveness to repeated, nonthreatening stimuli. Although habituation is well studied in vertebrates, little is known about how insects adjust their behaviour to repeated stressors in natural settings. We tested whether wild field crickets, Gryllus campestris , habituate or become sensitized to repeated simulated predator attacks, and whether these effects vary with threat intensity. Crickets' speed as they ran into their burrow in response to a vibrational stimulus did not change over repeated exposures. However, modest sensitization was observed: latency to re-emerge from the burrow increased and the distance from the burrow at which crickets settled decreased. Crickets also remained closer to the burrow in response to stronger stimuli, consistent with heightened sensitization. Re-emergence latency and escape speed were unaffected by stimulus intensity. Contrary to our predictions, individual crickets did not respond consistently across two vibrational stimulus types differing in magnitude. While some individuals increased their latency to re-emerge or postemergence distance more strongly under one stimulus than the other, others showed little or no change. These patterns suggest that only certain behaviours are flexible and that individuals varied in how strongly they adjusted these behaviours. Escape speed, by contrast, remained stable. Together, our results indicate sensitization, trait-specific flexibility and substantial individual variation in crickets’ responses to repeated disturbance. This is consistent with recent perspectives that view habituation and sensitization as context-dependent learning processes and highlights the diverse strategies animals use to manage risk in unpredictable environments.