Data from: Predator-prey interactions shape thermal patch use in a newt larvae-dragonfly nymph model

Thermal quality and predation risk are considered important factors influencing habitat patch use in ectothermic prey. However, how the predator’s food requirement and the prey’s necessity to avoid predation interact with their respective thermoregulatory strategies remains poorly understood. The recently developed ‘thermal game model’ predicts that in the face of imminent predation, prey should divide their time equally among a range of thermal patches. In contrast, predators should concentrate their hunting activities towards warmer patches. In this study, we test these predictions in a laboratory setup and an artificial environment that mimics more natural conditions. In both cases, we scored thermal patch use of newt larvae (prey) and free-ranging dragonfly nymphs (predators). Similar effects were seen in both settings. The newt larvae spent less time in the warm patch if dragonfly nymphs were present. The patch use of the dragonfly nymphs did not change as a function of prey availability, even when the nymphs were starved prior to the experiment. Our behavioral observations partially corroborate predictions of the thermal game model. In line with asymmetric fitness pay-offs in predator-prey interactions (the ‘life-dinner’ principle), the prey’s thermal strategy is more sensitive to the presence of predators than vice versa.

热环境质量与捕食风险，是影响变温猎物（ectothermic prey）栖息地斑块选择的关键因素。然而，捕食者的食物需求与猎物的避捕刚需，如何与其各自的体温调节策略产生交互作用，目前仍缺乏深入认知。新近提出的热博弈模型（thermal game model）预测：当面临迫近的捕食威胁时，猎物应在各类热斑块中平均分配活动时长；与之相对，捕食者应将狩猎活动集中于温度更高的斑块内。本研究通过实验室装置与模拟自然生境的人工环境，对上述两项预测展开验证。两类场景中，我们均记录了作为猎物（prey）的蝾螈幼虫与作为捕食者（predators）的自由活动蜻蜓稚虫的热斑块选择行为。两类实验设置均观测到了一致的效应：当蜻蜓稚虫存在时，蝾螈幼虫在温暖斑块中的停留时间显著减少；而蜻蜓稚虫的斑块选择行为并未随猎物可获得性的变化发生改变，即便实验前对稚虫进行了禁食处理亦是如此。本研究的行为观测结果部分佐证了热博弈模型的预测。结合捕食者-猎物互作中不对称的适合度收益（即“生命-晚餐原则（life-dinner principle）”），猎物的体温调节策略对捕食者的存在更为敏感，反之则不然。