As temperature increases, predator attack rate is more important to survival than a smaller window of prey vulnerability

Climate change can have strong effects on species interactions and community structure. Temperature-dependent effects on predator-prey interactions are a major mechanism through which these effects occur. To understand the net effects of predator attack rates and dynamic windows of prey vulnerability, we examined the impacts of temperature on the interaction of a caterpillar (Arctia virginalis) and its ant predator (Formica lasioides). We conducted field experiments to examine attack rates on caterpillars relative to temperature, ant abundance, and body size, and laboratory experiments to determine the effects of temperature on caterpillar growth. We modeled temperature-dependent survival based on the integrated effects of temperature-dependent growth and temperature- and size-dependent predation. Attack rates on caterpillars increased with warming and ant recruitment, but decreased with size. Caterpillar growth rates increased with temperature, narrowing the window of vulnerability. The model predicted net caterpillar survival would decrease with temperature, suggesting A. virginalis populations could be depressed with future climate warming. Theoretical work suggests the net outcome of predator-prey interactions with increasing temperature depends on the respective responses of interacting species in terms of velocity across space, whereas the present study suggests the importance of effects of temperature on prey window of vulnerability, or â velocityâ across time.气候变化可对物种互作与群落结构产生显著影响。温度依赖型效应对捕食者-猎物互作的影响，正是此类影响产生的核心机制之一。为阐明捕食者攻击速率与猎物易受攻击动态窗口的净效应，本研究探究了温度对灯蛾（Arctia virginalis）与其捕食者蚁类（Formica lasioides）之间互作的影响。我们开展了野外实验，以探究温度、蚁类多度与幼虫体型对灯蛾幼虫被捕食攻击率的影响；同时开展室内实验，明确温度对灯蛾幼虫生长的作用。本研究基于温度依赖型生长，以及温度和体型依赖型捕食的综合效应，构建了温度依赖型存活模型。灯蛾幼虫的被捕食攻击率随温度升高与蚁类招募量增加而上升，但随幼虫体型增大而下降；灯蛾幼虫的生长速率随温度升高而加快，从而缩小了其易受攻击的窗口。该模型预测，灯蛾幼虫的净存活率将随温度升高而下降，这表明未来气候变暖可能会抑制Arctia virginalis的种群规模。已有理论研究表明，随着温度升高，捕食者-猎物互作的净结果取决于互作物种在空间移动速率上的各自响应；而本研究则揭示了温度对猎物易受攻击窗口（即时间维度上的“移动速率”）的影响的重要性。