Department of Entomology and Center for Population Biology, University of California, Davis, California 95616, USA.
Am Nat. 2010 Jun;175(6):662-74. doi: 10.1086/652468.
Debates concerning the roles of different factors that may limit an organism's reproductive success pervade evolutionary ecology. We suggest that a broad class of limiting-factors problems involving essential resources or essential components of reproductive effort can be analyzed with an evolutionary application of Liebig's law of the minimum. We explore life-history evolution using the metaphor of an organism that must harvest two essential resources (resources 1 and 2) from a stochastically varying environment. Our models make three predictions. First, organisms should overinvest, relative to the deterministic case, in harvesting the resource whose per-offspring harvest cost is smaller. Second, at the optimum, organisms balance multiple fitness-limiting factors rather than being consistently limited by one factor. Third, the optimal investment in harvesting a resource is directly linked to the probability that the organism's fitness will be limited by that resource. Under temporal variation, the optimal proportional investment in harvesting resource 1 is equal to the probability that resource 1 will limit fitness. Our results help to explain why the responses of populations to environmental perturbations are hard to predict: as an organism transitions between different limiting factors, its responses to perturbations of those factors will likewise change.
关于可能限制生物体繁殖成功率的不同因素的作用的争论在进化生态学中普遍存在。我们建议，可以使用利比希最小定律的进化应用来分析涉及必要资源或生殖努力的重要组成部分的一类广泛的限制因素问题。我们使用生物体必须从随机变化的环境中收获两种必需资源（资源 1 和资源 2）的隐喻来探索生活史进化。我们的模型做出了三个预测。首先，与确定性情况相比，生物体应过度投资于收获每个后代的收获成本较小的资源。其次，在最佳状态下，生物体应平衡多种限制适应度的因素，而不是始终受到一个因素的限制。第三，收获资源的最佳投资与该资源限制生物体适应性的概率直接相关。在时间变化下，收获资源 1 的最优比例投资等于资源 1 将限制适应性的概率。我们的研究结果有助于解释为什么种群对环境干扰的反应难以预测：随着生物体在不同限制因素之间的转变，其对这些因素的干扰的反应也会发生变化。
