Centre d'Etudes Biologiques de Chizé, CNRS, Villiers-en-Bois, France.
PLoS One. 2012;7(1):e28924. doi: 10.1371/journal.pone.0028924. Epub 2012 Jan 11.
Dispersal theory generally predicts kin competition, inbreeding, and temporal variation in habitat quality should select for dispersal, whereas spatial variation in habitat quality should select against dispersal. The effect of predation on the evolution of dispersal is currently not well-known: because predation can be variable in both space and time, it is not clear whether or when predation will promote dispersal within prey. Moreover, the evolution of prey dispersal affects strongly the encounter rate of predator and prey individuals, which greatly determines the ecological dynamics, and in turn changes the selection pressures for prey dispersal, in an eco-evolutionary feedback loop. When taken all together the effect of predation on prey dispersal is rather difficult to predict. We analyze a spatially explicit, individual-based predator-prey model and its mathematical approximation to investigate the evolution of prey dispersal. Competition and predation depend on local, rather than landscape-scale densities, and the spatial pattern of predation corresponds well to that of predators using restricted home ranges (e.g. central-place foragers). Analyses show the balance between the level of competition and predation pressure an individual is expected to experience determines whether prey should disperse or stay close to their parents and siblings, and more predation selects for less prey dispersal. Predators with smaller home ranges also select for less prey dispersal; more prey dispersal is favoured if predators have large home ranges, are very mobile, and/or are evenly distributed across the landscape.
扩散理论通常预测，亲缘竞争、近亲繁殖和栖息地质量的时间变化应该选择扩散，而栖息地质量的空间变化应该选择反对扩散。捕食对扩散进化的影响目前还不清楚：因为捕食在空间和时间上都是可变的，所以不清楚捕食是否会在何时促进猎物的扩散。此外，猎物扩散的进化强烈影响捕食者和猎物个体的遭遇率，这极大地决定了生态动力学，并反过来改变了猎物扩散的选择压力，形成一个生态进化反馈循环。当所有这些因素综合在一起时，捕食对猎物扩散的影响是相当难以预测的。我们分析了一个空间显式的、基于个体的捕食者-猎物模型及其数学近似值，以研究猎物扩散的进化。竞争和捕食取决于局部而非景观尺度的密度，并且捕食的空间模式与使用受限栖息地范围的捕食者（例如，中央觅食者）的空间模式非常吻合。分析表明，个体预期要经历的竞争和捕食压力的平衡决定了猎物是应该扩散还是靠近它们的父母和兄弟姐妹，更多的捕食选择了更少的猎物扩散。栖息地范围较小的捕食者也选择了较少的猎物扩散；如果捕食者的栖息地范围较大、移动性较强且/或在整个景观中均匀分布，则更有利于猎物的扩散。
