Jr Research Group on Sexual Selection, Reproductive Biology Unit, German Primate Centre, Göttingen, Germany.
Department of Anthropology, New York University, 25 Waverly Place, New York, NY, 10003, USA.
Sci Rep. 2021 Feb 19;11(1):4251. doi: 10.1038/s41598-021-81163-1.
High social status is the primary determinant of reproductive success among group-living male mammals. Primates living in multimale-multifemale groups show the greatest variation in the strength of this link, with marked variation in reproductive skew by male dominance among species, dependent on the degree of female fertile phase synchrony, and the number of competing males. Here, we present data on two groups of wild crested macaques (Macaca nigra), living in the Tangkoko Reserve, Sulawesi, Indonesia. We investigated male monopolization of fertile females in 31 cycles of 19 females, and genetic paternity of 14 offspring conceived during the study period. We show that female fertile phase synchrony was low, that females had few mating partners in their fertile phase, and that dominant males monopolized a high proportion of consortships and matings, resulting in marked and steep mating and reproductive skew. We conclude that female cycle asynchrony provides the opportunity for strong direct male-male competition in crested macaques, resulting in monopolization of females by dominant males, consistent with their marked sexual dimorphism. Our study provides a test of the underlying factors that determine the relative occurrence and strength of different mechanisms of sexual selection, and the phenotypes that evolve as a result.
高社会地位是群居雄性哺乳动物生殖成功的主要决定因素。在多雄性-多雌性群体中生活的灵长类动物，在这种联系的强度上表现出最大的变化，雄性支配地位对雄性生殖优势的影响在物种间存在显著差异，这取决于雌性生育期同步性的程度，以及竞争雄性的数量。在这里，我们提供了来自印度尼西亚苏拉威西岛坦格库库保护区两个野生黑冠猕猴（Macaca nigra）群体的数据。我们调查了 19 只雌性猕猴 31 个周期中雄性对可育雌性的垄断情况，以及研究期间 14 只后代的遗传亲子关系。我们表明，雌性生育期同步性较低，雌性在生育期的交配对象较少，而优势雄性垄断了大部分交配和交配机会，导致明显而陡峭的交配和生殖优势。我们得出结论，雌性周期不同步为黑冠猕猴中的强烈直接雄性间竞争提供了机会，导致优势雄性对雌性的垄断，这与它们明显的性二态性一致。我们的研究检验了决定不同性选择机制的相对发生和强度以及由此产生的表型的潜在因素。
