Am Nat. 2021 Apr;197(4):473-485. doi: 10.1086/712996. Epub 2021 Feb 11.
AbstractModels of optimal group size need to identify the currency that correctly captures the fitness consequences of foraging. Although daily intake or daily net energy gain per animal are widely used as currencies, they are not ideal. They predict that all available time should be spent hunting and do not reflect performance during a hunt. We argue that the net rate while hunting is a better currency. Using an example based on the African wild dog, we illustrate the difference between maximizing daily net energy and net rate. Using the same example, we show that if foraging is limited by constraints on energy expenditure, then the optimal group size can be different from the size that maximizes the net rate while hunting. The direction of the effect depends on whether costs increase or decrease with group size. Furthermore, the proportion of time spent resting can be predicted. We suggest two novel approaches for future models: to consider the optimal hunting group size given a fixed group size and to investigate how the presence of dependent young may affect foraging behavior. We hope this will lead to meaningful conclusions on the role cooperative hunting has played in the evolution of sociality in social carnivores.
摘要 最优群体大小模型需要确定能够正确捕捉觅食对适应度影响的货币。虽然每日摄入量或动物每日净能量增益被广泛用作货币，但它们并不理想。它们预测所有可用的时间都应该用于狩猎，而不反映狩猎期间的表现。我们认为，狩猎时的净速率是一种更好的货币。我们使用一个基于非洲野犬的例子来说明最大化每日净能量和净速率之间的区别。使用相同的例子，我们表明如果觅食受到能量消耗的限制，那么最佳群体大小可能与最大化狩猎时净速率的大小不同。这种效果的方向取决于成本是随群体大小增加还是减少。此外，可以预测休息时间的比例。我们为未来的模型提出了两种新方法：考虑给定固定群体大小的最佳狩猎群体大小，并研究有依赖的幼崽存在如何影响觅食行为。我们希望这将对合作狩猎在社会食肉动物的社会性进化中所起的作用产生有意义的结论。
