Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, SL5 7PY, UK.
School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, NZ.
Ecol Lett. 2019 Nov;22(11):1734-1745. doi: 10.1111/ele.13334. Epub 2019 Aug 7.
The foraging behaviour of species determines their diet and, therefore, also emergent food-web structure. Optimal foraging theory (OFT) has previously been applied to understand the emergence of food-web structure through a consumer-centric consideration of diet choice. However, the resource-centric viewpoint, where species adjust their behaviour to reduce the risk of predation, has not been considered. We develop a mechanistic model that merges metabolic theory with OFT to incorporate the effect of predation risk on diet choice to assemble food webs. This 'predation-risk-compromise' (PR) model better captures the nestedness and modularity of empirical food webs relative to the classical optimal foraging model. Specifically, compared with optimal foraging alone, risk-mitigated foraging leads to more-nested but less-modular webs by broadening the diet of consumers at intermediate trophic levels. Thus, predation risk significantly affects food-web structure by constraining species' ability to forage optimally, and needs to be considered in future work.
物种的觅食行为决定了它们的饮食，因此也决定了新兴的食物网结构。最优觅食理论（OFT）以前曾被用于通过以消费者为中心的饮食选择来理解食物网结构的出现。然而，资源为中心的观点，即物种调整其行为以降低被捕食的风险，尚未被考虑。我们开发了一种机械模型，将代谢理论与 OFT 合并，以将捕食风险对饮食选择的影响纳入食物网组装中。与经典的最优觅食模型相比，这种“捕食风险妥协”（PR）模型更好地捕捉了经验食物网的嵌套性和模块性。具体而言，与仅最优觅食相比，风险缓解觅食通过拓宽中间营养级消费者的饮食，导致更嵌套但更少模块化的网络。因此，捕食风险通过限制物种最优觅食的能力显著影响食物网结构，需要在未来的工作中加以考虑。
