Ostner Julia, Nunn Charles L, Schülke Oliver
Integrative Primate Socio-Ecology Group, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.
Behav Ecol. 2008 Nov;19(6):1150-1158. doi: 10.1093/beheco/arn093.
Recent studies have uncovered remarkable variation in paternity within primate groups. To date, however, we lack a general understanding of the factors that drive variation in paternity skew among primate groups and across species. Our study focused on hypotheses from reproductive skew theory involving limited control and the use of paternity "concessions" by investigating how paternity covaries with the number of males, female estrous synchrony, and rates of extragroup paternity. In multivariate and phylogenetically controlled analyses of data from 27 studies on 19 species, we found strong support for a limited control skew model, with reproductive skew within groups declining as female reproductive synchrony and the number of males per group increase. Of these 2 variables, female reproductive synchrony explained more of the variation in paternity distributions. To test whether dominant males provide incentives to subordinates to resist matings by extragroup males, that is, whether dominants make concessions of paternity, we derived a novel prediction that skew is lower within groups when threat from outside the group exists. This prediction was not supported as a primary factor underlying patterns of reproductive skew among primate species. However, our approach revealed that if concessions occur in primates, they are most likely when female synchrony is low, as these conditions provide alpha male control of paternity that is assumed by concessions models. Collectively, our analyses demonstrate that aspects of male reproductive competition are the primary drivers of reproductive skew in primates.
最近的研究发现灵长类群体内的父权情况存在显著差异。然而，迄今为止，我们对于驱动灵长类群体间以及跨物种父权偏差变化的因素仍缺乏全面的了解。我们的研究聚焦于生殖偏差理论中的假设，这些假设涉及有限控制以及父权“让步”的运用，通过研究父权如何与雄性数量、雌性发情同步性以及群外交配率共同变化来进行探究。在对19个物种的27项研究数据进行的多变量和系统发育控制分析中，我们发现有力支持了有限控制偏差模型，即随着雌性生殖同步性和每组雄性数量的增加，群体内的生殖偏差会下降。在这两个变量中，雌性生殖同步性解释了父权分布中更多的变异。为了检验优势雄性是否会激励下属抵抗群外雄性的交配行为，也就是说，优势雄性是否会做出父权让步，我们得出了一个新的预测，即当存在来自群体外部的威胁时，群体内的偏差会更低。这一预测并未被支持为灵长类物种生殖偏差模式的主要潜在因素。然而，我们的方法表明，如果灵长类动物中存在让步行为，那么最有可能发生在雌性同步性较低的时候，因为这些条件提供了优势雄性对父权的控制，这是让步模型所假设的。总体而言，我们的分析表明雄性生殖竞争的各个方面是灵长类动物生殖偏差的主要驱动因素。
