Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
J Hum Evol. 2012 Apr;62(4):466-72. doi: 10.1016/j.jhevol.2012.01.006. Epub 2012 Mar 2.
Sexual selection is thought to drive the evolution of sexually dimorphic traits that increase male reproductive success. Despite a large degree of sexual dimorphism among haplorhine primates, phenotypic traits that may influence the reproductive success of males are largely unstudied due to long life spans and the difficulties in quantifying such traits non-invasively. Here we employ digital photogrammetry of body length and crest size, as well as ranking of the gluteal muscle size, to test whether these sexually dimorphic traits are associated with long-term measures of male reproductive success in western gorillas. Among 19 adult male gorillas monitored for up to 12.5 years, we found that all three phenotypic traits were positively correlated with the average number of mates per male, but only crest size and gluteal muscle size were significantly correlated with offspring survival and the annual rate of siring offspring that survive to weaning age. We discuss why such sexually dimorphic traits might be under ongoing selection in gorillas and other species.
性选择被认为是推动性二型特征进化的原因，这些特征可以提高雄性的繁殖成功率。尽管在阔鼻猴类灵长类动物中存在很大程度的性二型，但由于寿命长和难以非侵入性地量化这些特征，可能影响雄性繁殖成功率的表型特征在很大程度上仍未得到研究。在这里，我们使用身体长度和冠部大小的数字摄影测量法，以及臀肌大小的排序，来检验这些性二型特征是否与西部大猩猩雄性的长期繁殖成功率有关。在监测了长达 12.5 年的 19 只成年雄性大猩猩中，我们发现所有三种表型特征都与雄性的平均配偶数量呈正相关，但只有冠部大小和臀肌大小与后代的存活率以及每年有多少存活到断奶年龄的后代有关。我们讨论了为什么在大猩猩和其他物种中，这些性二型特征可能会持续受到选择。
