Okuyama Toshinori
Department of Entomology National Taiwan University Taipei Taiwan.
Ecol Evol. 2016 Dec 20;7(2):526-532. doi: 10.1002/ece3.2633. eCollection 2017 Jan.
The effects of the expected predation rate on population dynamics have been studied intensively, but little is known about the effects of predation rate variability (i.e., predator individuals having variable foraging success) on population dynamics. In this study, variation in foraging success among predators was quantified by observing the predation of the wolf spider on the cricket in the laboratory. A population model was then developed, and the effect of foraging variability on predator-prey dynamics was examined by incorporating levels of variation comparable to those quantified in the experiment. The variability in the foraging success among spiders was greater than would be expected by chance (i.e., the random allocation of prey to predators). The foraging variation was density-dependent; it became higher as the predator density increased. A population model that incorporates foraging variation shows that the variation influences population dynamics by affecting the numerical response of predators. In particular, the variation induces negative density-dependent effects among predators and stabilizes predator-prey dynamics.
预期捕食率对种群动态的影响已得到深入研究，但关于捕食率变异性（即捕食者个体具有不同的觅食成功率）对种群动态的影响却知之甚少。在本研究中，通过在实验室观察狼蛛对蟋蟀的捕食来量化捕食者之间觅食成功率的差异。然后建立了一个种群模型，并通过纳入与实验中量化水平相当的变异水平，研究了觅食变异性对捕食者 - 猎物动态的影响。蜘蛛之间觅食成功率的变异性大于随机预期（即猎物随机分配给捕食者）。觅食变异是密度依赖性的；随着捕食者密度的增加而变得更高。一个纳入觅食变异的种群模型表明，这种变异通过影响捕食者的数量反应来影响种群动态。特别是，这种变异在捕食者之间诱导出负密度依赖性效应，并稳定了捕食者 - 猎物动态。
