Rudolf Volker H W
Department of Biology, University of Virginia, Charlottesville, Virginia 22904, USA.
Ecology. 2007 Dec;88(12):2991-3003. doi: 10.1890/07-0179.1.
Cannibalistic and asymmetrical behavioral interactions between stages are common within stage-structured predator populations. Such direct interactions between predator stages can result in density- and trait-mediated indirect interactions between a predator and its prey. A set of structured predator-prey models is used to explore how such indirect interactions affect the dynamics and structure of communities. Analyses of the separate and combined effects of stage-structured cannibalism and behavior-mediated avoidance of cannibals under different ecological scenarios show that both cannibalism and behavioral avoidance of cannibalism can result in short- and long-term positive indirect connections between predator stages and the prey, including "apparent mutualism." These positive interactions alter the strength of trophic cascades such that the system's dynamics are determined by the interaction between bottom-up and top-down effects. Contrary to the expectation of simpler models, enrichment increases both predator and prey abundance in systems with cannibalism or behavioral avoidance of cannibalism. The effect of behavioral avoidance of cannibalism, however, depends on how strongly it affects the maturation rate of the predator. Behavioral interactions between predator stages reduce the short-term positive effect of cannibalism on the prey density, but can enhance its positive long-term effects. Both interaction types reduce the destabilizing effect of enrichment. These results suggest that inconsistencies between data and simple models can be resolved by accounting for stage-structured interactions within and among species.
在具有阶段结构的捕食者种群中，不同阶段之间的同类相食和不对称行为相互作用很常见。捕食者不同阶段之间的这种直接相互作用会导致捕食者与其猎物之间产生密度介导和性状介导的间接相互作用。使用一组结构化的捕食者 - 猎物模型来探究这种间接相互作用如何影响群落的动态和结构。对不同生态情景下阶段结构同类相食和行为介导的同类相食回避的单独和综合影响的分析表明，同类相食和行为介导的同类相食回避都可能导致捕食者不同阶段与猎物之间产生短期和长期的正向间接联系，包括“表观互利共生”。这些正向相互作用改变了营养级联的强度，使得系统动态由自下而上和自上而下效应之间的相互作用决定。与简单模型的预期相反，在存在同类相食或行为介导的同类相食回避的系统中，富集作用会增加捕食者和猎物的丰度。然而，行为介导的同类相食回避的影响取决于它对捕食者成熟率的影响强度。捕食者不同阶段之间的行为相互作用会降低同类相食对猎物密度的短期正向影响，但会增强其长期正向影响。两种相互作用类型都会降低富集作用的不稳定效应。这些结果表明，通过考虑物种内部和物种之间的阶段结构相互作用，可以解决数据与简单模型之间的不一致问题。
