Wild Crickets Can Adjust Escaping Speed Under Varying Predation Cues

Predator-prey dynamics impose strong selection pressures on the evolution of anti-predator strategies, which constitute a fundamental adaptive response in wild animals. However, these strategies incur energetic costs, requiring trade-offs with other fitness-related traits. While predator-prey interactions have been extensively studied, empirical evidence for behavioural plasticity in responses across predation risk gradients remains limited. We conducted field experiments on wild cricket (Gryllus campestris) nymphs in northern Spain, to investigate (1) how the intensity of predation cues influences escape speed adjustments and (2) whether anti-predator strategies vary by sex, developmental stage and according to thermal conditions. We simulated two levels of vibrational cues: low-intensity and high-intensity. Contrary to our threat-sensitivity predictions, nymphs exhibited slower escape responses to high-intensity cues. This pattern may reflect ecological relevance: cricket predators are primarily small vertebrates which will generate lower intensity vibrational cues than passing ungulates. Consistent with our previous findings in adults, escape speed in nymphs increased with body temperature. However, sex-dependent variation was observed only in adults, not in nymphs, suggesting developmental differences in anti-predator strategies.