van de Wolfshaar K E, de Roos A M, Persson L
Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands.
Am Nat. 2006 Jul;168(1):62-75. doi: 10.1086/505156. Epub 2006 Jun 12.
Growth in body size during ontogeny often results in changes in diet, leading to life-history omnivory. In addition, growth is often dependent on food density. Using a physiologically structured population model, we investigated the effects of these two aspects of individual growth in a system consisting of two size-structured populations, an omnivorous top predator and an intermediate consumer. With a single shared resource for both populations, we found that life-history omnivory decreases the likelihood of coexistence between top predator and intermediate consumer in this intraguild predation (IGP) system. This result contrasts with previous unstructured models and stage-structured models without food-dependent development. Food-dependent development and size-dependent foraging abilities of the predator resulted in a positive feedback between foraging success on the shared resource at an early life stage and foraging success on the intermediate consumer later in life. By phenomenologically incorporating this feedback in an unstructured IGP model, we show that it also demotes coexistence in this simple setting, demonstrating the robustness of the negative effect of this feedback.
个体发育过程中身体大小的增长通常会导致饮食变化，从而产生生活史杂食性。此外，生长往往依赖于食物密度。我们使用一个生理结构种群模型，在一个由两个大小结构种群组成的系统中研究了个体生长的这两个方面的影响，这两个种群分别是杂食性顶级捕食者和中间消费者。对于这两个种群共享单一资源的情况，我们发现生活史杂食性降低了这个种内捕食（IGP）系统中顶级捕食者和中间消费者共存的可能性。这一结果与之前的非结构化模型以及没有食物依赖发育的阶段结构化模型形成对比。捕食者的食物依赖发育和大小依赖觅食能力导致了早期生命阶段对共享资源的觅食成功与后期对中间消费者的觅食成功之间的正反馈。通过在非结构化IGP模型中从现象学角度纳入这种反馈，我们表明在这个简单环境中它也会降低共存可能性，证明了这种反馈负面影响的稳健性。
