Achilles' heel of sociality revealed by energetic poverty trap in cursorial hunters
Achilles' heel of sociality revealed by energetic poverty trap in cursorial hunters
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DOI：
10.1086/590965
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发表时间：
2008-10-01
影响因子：
2.9
通讯作者：
Macdonald, David W.
中科院分区：
文献类型：
--
作者：
Rasmussen, Gregory S. A.;Gusset, Markus;Macdonald, David W.
本研究实证检验了两个基础生态理论：（1）群体狩猎是社会性进化的驱动力;（2）物种具有有限的能量潜力，因此增加的维护成本导致生殖努力减少。使用22包非洲野狗（Lycaon pictus）的活动和猎物数据，我们参数化模型，详细说明了合作狩猎的精力充沛的成本/效益。较大的包装尺寸增加觅食时间，猎物的大小，捕获概率，同时减少追逐距离，导致能量摄入量的净率迅速增加到一个包的大小为5，达到峰值在10个人，然后下降。由于精简的身体计划需要hypercursoriality限制胃容量在较小的包，它被证明，群体狩猎的好处，而不是增加广泛觅食的捕食者“坐着等待”的。生殖努力，出生的幼崽数量来衡量，揭示了较小的窝与减少包大小，验证有限能量理论，并强调了“贫困陷阱”，较小的群体有较低的觅食收益，较小的窝，并增加了脆弱性灭绝。因此，这些结果证明了一个机械的例子，普遍选择最大的身体大小（科普的规则），导致一个宏观进化棘轮，社会性与hypercursoriality是背叛了阿喀琉斯之踵。
This study empirically tests two foundation ecological theories: (1) pack hunting is a driver for the evolution of sociality; and (2) species have a finite energy potential, whereby increased maintenance costs result in decreased reproductive effort. Using activity and prey data from 22 packs of African wild dogs (Lycaon pictus), we parameterized a model detailing the energetic cost/benefit of cooperative hunting. Larger pack size increased foraging time, prey size, and capture probability while reducing chase distance, resulting in a rapidly increasing net rate of energy intake up to a pack size of five, which peaked at 10 individuals and then declined. With a streamlined body plan necessary for hypercursoriality limiting stomach capacity in smaller packs, it was demonstrated that the group hunting benefit will rather accrue to widely foraging predators than to "sit-and-wait" ones. Reproductive effort, measured by the number of pups born, revealed smaller litters with decreasing pack size, validated finite energy theory, and highlighted a "poverty trap" where smaller groups have lower foraging gains, smaller litters, and increased vulnerability to extirpation. Consequently, these results demonstrated a mechanistic example of pervasive selection for maximal body size (Cope's rule), leading to a macroevolutionary ratchet, where sociality linked to hypercursoriality is betrayed by an Achilles' heel.