Turner Andrew M, Fetterolf Shelley A, Bernot Randall J
Department of Biology, Clarion University, Clarion, PA 16214, USA e-mail:
Oecologia. 1999 Feb;118(2):242-247. doi: 10.1007/s004420050724.
Predators can alter the outcome of ecological interactions among other members of the food web through their effects on prey behavior. While it is well known that animals often alter their behavior with the imposition of predation risk, we know less about how other features of predators may affect prey behavior. For example, relatively few studies have addressed the effects of predator identity on prey behavior, but such knowledge is crucial to understanding food web interactions. This study contrasts the behavioral responses of the freshwater snail Physellagyrina to fish and crayfish predators. Snails were placed in experimental mesocosms containing caged fish and crayfish, so the only communication between experimental snails and their predators was via non-visual cues. The caged fish and crayfish were fed an equal number of snails, thereby simulating equal prey mortality rates. In the presence of fish, the experimental snails moved under cover, which confers safety from fish predators. However, in the presence of crayfish, snails avoided benthic cover and moved to the water surface. Thus, two species of predators, exerting the same level of mortality on prey, induced very different behavioral responses. We predict that these contrasting behavioral responses to predation risk have important consequences for the interactions between snails and their periphyton resources.
捕食者可以通过影响猎物行为来改变食物网中其他成员之间的生态相互作用结果。虽然动物常常会因捕食风险的存在而改变自身行为，这一点广为人知，但对于捕食者的其他特征如何影响猎物行为，我们了解得还较少。例如，相对较少的研究探讨了捕食者身份对猎物行为的影响，但这类知识对于理解食物网相互作用至关重要。本研究对比了淡水蜗牛Physella gyrina对鱼类和小龙虾这两种捕食者的行为反应。将蜗牛放置在含有被关在笼中的鱼和小龙虾的实验中型生态系统中，这样实验蜗牛与其捕食者之间唯一的交流途径就是通过非视觉线索。给被关在笼中的鱼和小龙虾投喂数量相等的蜗牛，从而模拟相等的猎物死亡率。在有鱼存在的情况下，实验蜗牛会移动到隐蔽处，这能使其免受鱼类捕食者的攻击。然而，在有小龙虾存在的情况下，蜗牛会避开底栖隐蔽处并移动到水面。因此，两种捕食者对猎物造成相同程度的死亡率，却引发了截然不同的行为反应。我们预测，这些对捕食风险的不同行为反应对于蜗牛与其附生藻类资源之间的相互作用具有重要影响。
