Vijayan Sundararaj, Kotler Burt P, Abramsky Zvika
Department of Life Sciences, Ben Gurion University of the Negev, Beer Sheva 8410501, Israel.
The Jacob Blaustein Institute for Desert Research, Mitrani Department of Desert Ecology, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 84990, Israel.
Behav Processes. 2017 May;138:91-95. doi: 10.1016/j.beproc.2017.02.016. Epub 2017 Feb 21.
Prey individuals are often distributed heterogeneously in the environment, and their abundances and relative availabilities vary among patches. A foraging predator should maximize energetic gains by selectively choosing patches with higher prey density. However, catching behaviorally responsive and group-forming prey in patchy environments can be a challenge for predators. First, they have to identify the profitable patches, and second, they must manage the prey's sophisticated anti-predator behavior. Thus, the forager and its prey have to continuously adjust their behavior to that of their opponent. Given these conditions, the foraging predator's behavior should be dynamic with time in terms of foraging effort and prey capture rates across different patches. Theoretically, the allocation of its time among patches of behaviorally responsive prey should be such that it equalizes its prey capture rates across patches through time. We tested this prediction in a model system containing a predator (little egret) and group-forming prey (common gold fish) in two sets of experiments in which (1) patches (pools) contained equal numbers of prey, or in which (2) patches contained unequal densities of prey. The egret equalized the prey capture rate through time in both equal and different density experiments.
猎物个体在环境中往往分布不均，其数量和相对可利用性在不同斑块间存在差异。觅食的捕食者应通过选择性地选择猎物密度较高的斑块来实现能量获取最大化。然而，在斑块状环境中捕捉具有行为反应能力且会形成群体的猎物对捕食者来说可能是一项挑战。首先，它们必须识别出有利可图的斑块，其次，它们必须应对猎物复杂的反捕食行为。因此，觅食者及其猎物必须不断根据对手的行为来调整自身行为。在这些条件下，觅食捕食者的行为在觅食努力和不同斑块间的猎物捕获率方面应随时间动态变化。从理论上讲，其在有行为反应能力的猎物斑块间的时间分配应使得它在不同斑块间随时间均衡猎物捕获率。我们在一个模型系统中对这一预测进行了测试，该模型系统包含一个捕食者（小白鹭）和会形成群体的猎物（普通金鱼），进行了两组实验，其中（1）斑块（水池）中猎物数量相等，或者（2）斑块中猎物密度不等。在猎物密度相等和不等的实验中，白鹭均随时间均衡了猎物捕获率。
