Am Nat. 2020 Apr;195(4):649-663. doi: 10.1086/707392. Epub 2020 Feb 28.
Shadow competition, the interception of prey by sit-and-wait predators closest to the source of prey arrival, is prevalent in clusters of sit-and-wait predators. Peripheral positions in the cluster receive more prey and should thus be more frequently occupied. Models predicting spatial positioning in groups, however, usually ignore variability among group members. Here, I used a simulation model to determine conditions under which small and large sit-and-wait predators, which differ in their attack range, should differ in their spatial positions in the cluster. Small predators occupied peripheral positions more frequently than large predators at the simulation beginning, while the opposite held true as time advanced. Because of the large and small attack range of large and small predators, respectively, small predators mistakenly relocated away from peripheral positions, while large predators did not relocate fast enough from inferior central positions. Any factor that moderated the frequent relocations of small predators or had the opposite effect on large predators assisted small or large predators, respectively, in reaching the more profitable peripheral positions. Furthermore, any factor elevating shadow competition led to longer occupation of the periphery by large predators. This model may explain why sit-and-wait predators are not homogenously distributed in space according to size.
阴影竞争，即最接近猎物到达源的坐待捕食者对猎物的拦截，在坐待捕食者群中很普遍。群集中的外围位置接收更多的猎物，因此应该更频繁地被占据。然而，预测群体中空间定位的模型通常忽略了群体成员之间的可变性。在这里，我使用模拟模型来确定具有不同攻击范围的小和大坐待捕食者在群体中的空间位置应该有所不同的条件。在模拟开始时，小捕食者比大捕食者更频繁地占据外围位置，而随着时间的推移，情况则相反。由于大、小捕食者的攻击范围分别较大、小，小捕食者错误地从外围位置重新定位，而大捕食者从较差的中心位置不能快速重新定位。任何缓和小捕食者频繁重新定位的因素或对大捕食者产生相反影响的因素，都分别有助于小或大捕食者到达更有利可图的外围位置。此外，任何加剧阴影竞争的因素都会导致大捕食者占据外围位置的时间更长。该模型可以解释为什么坐待捕食者在空间上不是根据大小均匀分布的。
