Predator size interacts with habitat structure to determine the allometric scaling of the functional response
Predator size interacts with habitat structure to determine the allometric scaling of the functional response
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捕食者的大小与栖息地结构相互作用，以确定功能反应的异速生长尺度
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
B. Griffen
中科院分区：
文献类型：
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作者：
Benjamin J. Toscano;B. Griffen
虽然捕食者的身体大小和栖息地结构提供的猎物避难所都已被确定为影响功能反应的主要因素(人均消耗率作为猎物密度的函数)，但这些因素之间的潜在相互作用很少被探索。利用蟹类捕食者(Panopeus Herbstii)-贻贝猎物(Brachidontes Exustus)系统，我们研究了牡蛎(Crassostrea Virgiica)礁栖息地功能反应的异速生长尺度，牡蛎群中的缝隙为贻贝提供了躲避捕食的避难所。对贻贝分布的实地调查表明，当贻贝密度较高时，贻贝更接近集群外围，表明避难所有饱和的潜力。在功能反应实验中，大蟹在低捕食密度下的摄食率低于小蟹，而在高捕食密度下则相反。具体而言，攻击率系数和处理时间均随蟹的大小呈非线性下降。另一项操作显示，在低猎物密度下，与小型蟹相比，大型蟹从缝隙中操纵爪子和身体从缝隙中提取贻贝的能力受到结构化栖息地的抑制，从而降低了它们的攻击率。在高猎物密度时，缝隙是饱和的，迫使贻贝聚集在集群的边缘，那里的螃蟹只受处理时间的限制。我们的研究揭示了一种潜在的一般机制，即栖息地结构提供的捕食者避难所的质量取决于捕食者的相对大小。因此，改变自然蟹类大小分布或降低礁石栖息地结构的人为影响可能会威胁到礁蟹-贻贝相互作用的长期稳定性。
While both predator body size and prey refuge provided by habitat structure have been established as major factors influencing the functional response (per capita consumption rate as a function of prey density), potential interactions between these factors have rarely been explored. Using a crab predator (Panopeus herbstii) – mussel prey (Brachidontes exustus) system, we examined the allometric scaling of the functional response in oyster (Crassostrea virginica) reef habitat, where crevices within oyster clusters provide mussels refuge from predation. A field survey of mussel distribution showed that mussels attach closer to the cluster periphery at high mussel density, indicating the potential for saturation of the refuge. In functional response experiments, the consumption rate of large crabs was depressed at low prey density relative to small crabs, while at high prey density the reverse was true. Specifically, the attack rate coefficient and handling time both decreased non-linearly with crab size. An additional manipulation revealed that at low prey densities, the ability of large crabs to maneuver their claws and bodies to extract mussels from crevices was inhibited relative to small crabs by the structured habitat, reducing their attack rate. At high prey densities, crevices were saturated, forcing mussels to the edge of clusters where crabs were only limited by handling time. Our study illuminates a potentially general mechanism where the quality of the prey refuge provided by habitat structure is dependent on the relative size of the predator. Thus anthropogenic influences that alter the natural crab size distribution or degrade reef habitat structure could threaten the long-term stability of the crab – mussel interaction in reefs.