Department of Ecology, 310 Lewis Hall, Montana State University, Bozeman, Montana 59717, USA.
Ecology. 2011 Dec;92(12):2190-5. doi: 10.1890/11-0327.1.
Risk effects, or the costs of antipredator behavior, can comprise a large proportion of the total effect of predators on their prey. While empirical studies are accumulating to demonstrate the importance of risk effects, there is no general theory that predicts the relative importance of risk effects and direct predation. Working toward this general theory, it has been shown that functional traits of predators (e.g., hunting modes) help to predict the importance of risk effects for ecosystem function. Here, I note that attributes of the predator, the prey, and the environment are all important in determining the strength of antipredator responses, and I develop hypotheses for the ways that prey functional traits might influence the magnitude of risk effects. In particular, I consider the following attributes of prey: group size and dilution of direct predation risk, the degree of foraging specialization, body mass, and the degree to which direct predation is additive vs. compensatory. Strong tests of these hypotheses will require continued development of methods to identify and quantify the fitness costs of antipredator responses in wild populations.
风险效应，或抗捕食行为的成本，可以构成捕食者对猎物总效应的很大一部分。虽然实证研究正在积累，以证明风险效应的重要性，但还没有一个普遍的理论来预测风险效应和直接捕食的相对重要性。为了建立这个一般理论，已经表明捕食者的功能特征（例如，捕食方式）有助于预测风险效应对生态系统功能的重要性。在这里，我注意到，捕食者、猎物和环境的属性在决定抗捕食反应的强度方面都很重要，我提出了一些假设，说明猎物功能特征可能会影响风险效应的大小。特别是，我考虑了以下猎物属性：群体大小和直接捕食风险的稀释、觅食专业化程度、体重以及直接捕食是附加的还是补偿的程度。这些假设的强有力检验将需要继续开发方法，以确定和量化野生种群中抗捕食反应的适应代价。
