Emergent impacts of cannibalism and size refuges in prey on intraguild predation systems
Emergent impacts of cannibalism and size refuges in prey on intraguild predation systems
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DOI：
10.1007/s00442-008-1107-x
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发表时间：
2008-10-01
期刊：
影响因子：
2.7
通讯作者：
Armstrong, Joanna
中科院分区：
文献类型：
--
作者：
Rudolf, Volker H. W.;Armstrong, Joanna
许多生物在发育过程中由于大小的巨大变化而经历个体发育生态位的变化。这些个体发育变化可以改变个体的营养位置、跨物种的生态相互作用的类型和强度，并允许物种内部的自相残杀。在这项研究中，我们问一个大小的避难所和食人者在猎物中的相互作用是否以及如何改变行会内捕食(IGP)系统的动态。通过控制大型食肉蜻蜓幼虫(Aeshna Umbrosa)和捕食性蜻蜓幼虫(Anax Junius)的组成，我们发现食肉蜻蜓幼虫与捕食者之间的相互作用是非线性的，并提高了猎物的存活率。捕食者和捕食者共享的最终资源群落的结构在小蜻蜓处理和大蜻蜓处理之间存在差异，但不同物种的大小类别之间没有差异。总体而言，当暴露于同种食人者或捕食者时，小型捕食者阶段在微生境使用和避难所使用方面显示出类似的变化，而大型食人者没有表现出明显的反捕食者反应。然而，进一步的行为实验显示，当个体暴露在食人族或捕食者面前时，特定的行为成分，如个体之间的距离或活动数量，会有所不同。这表明个体区分同种或异种捕食者。此外，在类似的实验中，大型食人者和捕食者在暴露于同种生物而不是彼此时表现出不同的行为。这些行为的变化与观察到的猎物存活率的增加是一致的。总体而言，研究结果表明，自相残杀和个体发育生态位转移可以导致行为中介的间接相互作用，从而减少捕食者对猎物死亡率的影响，并改变IGP系统的相互作用。然而，它们也表明，大小不是唯一的决定因素，在预测群落的动态时，我们还需要考虑物种特性。
Many organisms undergo ontogenetic niche shifts due to considerable changes in size during their development. These ontogenetic shifts can alter the trophic position of individuals, the type and strength of ecological interactions across species, and allow for cannibalism within species. In this study we ask if and how the interaction of a size refuge and cannibalism in the prey alters the dynamics of intraguild predation (IGP) systems. By manipulating the composition of large cannibalistic (Aeshna umbrosa) and predatory (Anax junius) dragonfly larvae in mesocosms we show that the interaction of cannibals and predators was non-linear and increased the survival of prey. The structure of the final resource community shared by prey and predator differed between small and large dragonfly treatments but not within size classes across species. In general, the small prey stage showed similar shifts in microhabitat use and refuge use when exposed to either conspecific cannibals or predators, while large cannibals showed no clear anti-predator response. However, further behavioral experiments revealed that specific behavioral components, such as distances between individuals or number of movements, differed when individuals were exposed to either cannibals or predators. This indicates that individuals discriminated between conspecific or heterospecific predators. Furthermore, in similar experiments large cannibals and predators showed different behaviors when exposed to conspecifics rather than to each other. These changes in behavior are consistent with the observed increase in prey survival. In general, the results indicate that cannibalism and ontogenetic niche shifts can result in behavior-mediated indirect interactions that reduce the impact of the predator on the mortality of its prey and alter the interactions of IGP systems. However, they also indicate that size is not the sole determinant and that we also need to account for the species identity when predicting the dynamics of communities.