Predator size and phenology shape prey survival in temporary ponds
Predator size and phenology shape prey survival in temporary ponds
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捕食者的体型和物候决定了临时池塘中猎物的生存
作者：
M. C. Urban
理论上的努力表明，捕食者和猎物的相对大小可以塑造社区动态，食物网的结构和生活史的进化。然而，这项工作的大部分假设静态捕食者和猎物的身体大小。捕食者和被捕食者的招募时间和生长模式有可能改变捕食者-被捕食者相互作用的强度。在这项研究中，我研究了如何捕食者的大小动态在40个临时池塘在3年的时间内影响的生存斑点蝾螈（Ambystoma maculatum）幼虫。在整个群落中，间隙限制的捕食者丰富度（而不是大小）与栖息地持续时间（池塘持久性）相关。在社区内，平均差距有限的捕食者的大小随着生长季节的进展而减少。这种规模的减少发生，因为猎物个人成长为一个身体大小的避难所，因为最大的捕食者离开池塘中的季节。两个大型的捕食性蝾螈：大理石纹蝾螈幼虫（Ambystoma opacum）和红斑蝾螈成年人（Notophthalmus viridescens）的发生，预计在时间和空间上的间隙有限的捕食风险升高。最大的限隙捕食者A. opacum，预测A.斑螟幼虫在田间的存活率。大型肉食性蝾螈在池塘中的分布和时间上的不同，预计会导致不同的群落动态，并产生不同的自然选择对早期生长和身体大小在A。斑点。一般来说，对捕食者大小的动态视角往往是理解物种相互作用的生态学和进化所必需的。这将是特别真实的，在经常干扰或季节性的栖息地，物候和个体发育相互作用，以确定身体大小的不对称性。
Theoretical efforts suggest that the relative sizes of predators and their prey can shape community dynamics, the structure of food webs, and the evolution of life histories. However, much of this work has assumed static predator and prey body sizes. The timing of recruitment and the growth patterns of both predator and prey have the potential to modify the strength of predator–prey interactions. In this study, I examined how predator size dynamics in 40 temporary ponds over a 3-year period affected the survival of spotted salamander (Ambystoma maculatum) larvae. Across communities, gape-limited predator richness, but not size, was correlated with habitat duration (pond permanence). Within communities, mean gape-limited predator size diminished as the growing season progressed. This size reduction occurred because prey individuals grew into a body size refuge and because the largest of the predators left ponds by mid-season. Elevated gape-limited predation risk across time and space was predicted by the occurrence of two large predatory salamanders: marbled salamander larvae (Ambystoma opacum) and red-spotted newt adults (Notophthalmus viridescens). The presence of the largest gape-limited predator, A. opacum, predicted A. maculatum larval survival in the field. The distribution of large predatory salamanders among ponds and across time is expected to lead to differing community dynamics and to generate divergent natural selection on early growth and body size in A. maculatum. In general, a dynamic perspective on predator size often will be necessary to understand the ecology and evolution of species interactions. This will be especially true in frequently disturbed or seasonal habitats where phenology and ontogeny interact to determine body size asymmetries.