PRF/J: Lethal and Nonlethal Effects of Predators on Prey

捕食者通过捕食个体和影响猎物本身的行为来影响猎物种群和猎物。尽管致命性和非致命性捕食者-猎物相互作用都受到了关注，但鲜有经验证据表明每种作用的相对重要性，或致命性和非致命性捕食者效应如何相互作用影响猎物性能、种群动态、物种相互作用和分布。以前的研究要么衡量了捕食的整体影响(即致命和非致命的共同作用)，要么衡量了单独的非致命影响。由于捕食的致命性和非致命性效应可能具有相反的影响(例如，对猎物的生长速度)，因此不能从这些实验中确定捕食的组成部分后果。将进行实验室实验，以评估幼虫齿齿对其幼虫无尾两栖动物猎物的致死和非致死效应，以及现场实验，以确定致命和非致命性捕食者对自然猎物种群的影响。捕食者-猎物相互作用的复杂性质意味着，当两种类型的捕食者效应都发生时，对猎物性能的预测并不直观。这项研究的另一个目标是开发一个概念框架，用于理解捕食者对猎物生长和生存的致命性和非致命性影响。从这项工作中获得的见解应该具有普遍性，因为蝌蚪表现出的各种行为反应在许多其他类群中也很明显(例如，鱼、昆虫、甲壳类和哺乳动物)。现场测试是必要的，以检测结果在多大程度上是特定环境(人工涉水池)的人工制品。这项研究的目标之一是更真实地数学建模觅食行为和捕食风险/收益之间的猎物性能关系。认识到捕食对猎物影响的综合性质，应该会改变生态学家从概念上看待群落的方式。如果高阶效应普遍发生在猎物和捕食者之间，那么生态学家就不太可能像一些人希望的那样，理解基于两两相互作用的群落模式(积木方法)。成功预测种群动态和群落结构的生态模型需要包含物种之间的间接和直接相互作用。

Predators affect prey populations and prey by consuming individuals and by influencing prey behavior itself. Despite the attention that both lethal and non-lethal predator-prey interactions have received, little empirical evidence of the relative importance of each, or of how lethal and non-lethal predator effects interact with each other to influence prey performance, population dynamics, species interactions and distributions, is available. Previous research has either measured the entire effect of predation (i.e., lethal and non-lethal together) or the isolated non-lethal effect. Because lethal and non-lethal effects of predation can have opposing influences (e.g., on prey growth rate), the component consequences of predation cannot be determined from these experiments. Laboratory experiments to estimate lethal and non-lethal effects of a larval odonate on its larval anuran prey over a gradient of density dependence among prey, and a field experiment to determine lethal and non-lethal predator impacts on natural prey populations will be performed. The complex nature of predator-prey interactions means that predictions of prey performance are not intuitive when both types of predator effects are occurring. A further goal of this study is to develop a conceptual framework for understanding effects of predators that account for both lethal and non-lethal influences on prey growth and survivorship. %%% Insights gained from this work ought to have generality because the sorts of behavioral responses exhibited by tadpoles are also evident within many other taxa (fish, insects, crustaceans, and mammals for instance). Field tests are necessary in order to detect the extent to which results are artifacts of the specific setting (artificial wading pools). One of the goals of this investigation is to more realistically mathematically model prey performance relationships between foraging behavior and predation risk/gain. Recognition of the composite nature of predation effects on prey should alter the way ecologists view communities conceptually. If higher order effects occur commonly among prey and predators, then it will not likely be possible, as some have hoped, for ecologists to understand community patterns based on pairwise interactions (a building block approach). Ecological models that successfully predict population dynamics and community structure will need to incorporate both indirect as well as direct interactions among species.