Complex multi-predator effects on demographic habitat selection and community assembly in colonizing insects

Running the gauntlet of predators consumes critical time and energy resources, as all species are vulnerable to one or, typically, more predators at some life stage. Prey employ a vast array of mechanisms to avoid predation, and predators, likewise, come in a bewildering variety. Thus, defensive adaptations are rarely one size fits all. Considerable work has addressed multi-predator consumptive effects, but we now know that non-consumptive effects of predators can dramatically impact individuals, (meta)populations, and (meta)communities. However, little is known regarding the community-wide dynamics of non-consumptive effects generated by multiple predators. Predator avoidance by choosing a patch that is free of a particular predator or predators can be the most effective strategy if conditions at colonization are a reliable predictor of absence, which is often true for fish in freshwater systems. We experimentally manipulated composition of the predator assemblage in aquatic mesocosms ...直面各类捕食者的威胁会消耗生物至关重要的时间与能量资源，因为所有物种在其生命史的某一阶段，都会受到一种——通常是多种——捕食者的威胁。猎物演化出了多种多样的防御机制以规避捕食，而捕食者本身同样种类纷繁复杂。因此，防御适应策略极少能做到普适通用。已有诸多研究针对多捕食者的消耗性效应（consumptive effects）展开探讨，但如今我们已然知晓，捕食者的非消耗性效应（non-consumptive effects）会对个体、异质种群(meta-population)以及异质群落(meta-community)产生显著影响。然而，目前针对多捕食者所引发的非消耗性效应的群落尺度动态变化，我们仍知之甚少。若定植时的环境条件能够可靠预判捕食者的缺失情况——这一情形在淡水生态系统的鱼类中尤为常见——那么通过选择不含某一种或多种捕食者的生境斑块(patch)来规避捕食，便是最为有效的策略。我们在水生中宇宙(mesocosms)实验系统中，对捕食者群落的组成开展了实验操控……