Consumers face numerous risks that can be minimized by incorporating different life-history strategies. How much and when a consumer adds to its energetic reserves or invests in reproduction are key behavioral and physiological adaptations that structure communities. Here we develop a theoretical framework that explicitly accounts for stochastic fluctuations of an individual consumer's energetic reserves while foraging and reproducing on a landscape with resources that range from uniformly distributed to highly clustered. First, we show that the selection of alternative life histories depends on both the mean and variance of resource availability, where depleted and more stochastic environments promote investment in each reproductive event at the expense of future fitness as well as more investment per offspring. We then show that if resource variance scales with body size due to landscape clustering, consumers that forage for clustered foods are susceptible to strong Allee effects, increasing extinction risk. Finally, we show that the proposed relationship between resource distributions, consumer body size, and emergent demographic risk offers key ecological insights into the evolution of large-bodied grazing herbivores from small-bodied browsing ancestors.

中文翻译：

---

缩放风险格局可驱动最佳的生活史策略和放牧的演变。

消费者面临众多风险，可以通过采用不同的生命历史策略来最大程度地降低这些风险。消费者增加多少精力以及何时增加精力或投资于繁殖是构成社区的关键行为和生理适应。在这里，我们建立了一个理论框架，明确地说明了个人消费者的高能储备的随机波动，同时在景观范围内觅食和繁殖，资源范围从均匀分布到高度聚集。首先，我们表明替代生活史的选择取决于资源可用性的均值和方差，在这种情况下，枯竭的和更加随机的环境会促进每个生殖活动的投资，但会损害未来的适应性，并且会增加每个后代的投资。然后，我们表明，如果由于景观聚类而导致资源差异随身体大小而变化，则以聚类食品为食的消费者很容易受到Allee的强烈影响，从而增加灭绝的风险。最后，我们表明，资源分布，消费者身体大小和紧急人口风险之间的拟议关系为从小体型浏览祖先进化出大体放牧食草动物提供了重要的生态学见解。