Female reproductive maturation is a critical life-history milestone, initiating an individual's reproductive career. Studies in social mammals have often focused on how variables related to nutrition influence maturation age in females. However, parallel investigations have identified conspicuous male-mediated effects in which female maturation is sensitive to the presence and relatedness of males. Here, we evaluated whether the more "classic" socioecological variables (i.e., maternal rank, group size) predict maturation age in wild geladas-a primate species with known male-mediated effects on maturation and a grassy diet that is not expected to generate intense female competition. Females delayed maturation in the presence of their fathers and quickly matured when unrelated, dominant males arrived. Controlling for these male effects, however, higher-ranking daughters matured at earlier ages than lower-ranking daughters, suggesting an effect of within-group contest competition. However, contrary to predictions related to within-group scramble competition, females matured earliest in larger groups. We attribute this result to either: 1) a shift to "faster" development in response to the high infant mortality risk posed by larger groups; or 2) accelerated maturation triggered by brief, unobserved male visits. While earlier ages at maturation were indeed associated with earlier ages at first birth, these benefits were occasionally offset by male takeovers, which can delay successful reproduction via spontaneous abortion. In sum, rank-related effects on reproduction can still occur even when socioecological theory would predict otherwise, and males (and the risks they pose) may prompt female maturation even outside of successful takeovers.

中文翻译：

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雌性狮尾狮成熟年龄的社会驱动因素。

女性生殖成熟是一个重要的生命史里程碑，启动了个人的生殖生涯。对社会性哺乳动物的研究通常集中在与营养相关的变量如何影响雌性成熟年龄。然而，平行调查已经确定了显着的男性介导效应，其中女性成熟对男性的存在和相关性敏感。在这里，我们评估了更“经典”的社会生态变量（即母系等级、群体大小）是否可以预测野生狮尾狮的成熟年龄——一种已知雄性介导的成熟影响的灵长类动物，以及预计不会产生强烈的草食女性竞争。雌性在其父亲在场时会延迟成熟，而在无关的、占主导地位的雄性到来时会迅速成熟。控制这些男性效应，然而，排名较高的女儿比排名较低的女儿成熟得早，这表明群体内竞争的影响。然而，与有关组内争夺竞争的预测相反，雌性在较大的群体中成熟最早。我们将此结果归因于：1) 转向“更快”发展以应对较大群体造成的高婴儿死亡率风险；或 2) 由短暂的、未被观察到的男性访问引发的加速成熟。虽然早熟确实与早育有关，但这些好处偶尔会被男性接管所抵消，这可能会通过自然流产延迟成功繁殖。总之，即使社会生态学理论做出相反的预测，等级相关的繁殖效应仍然会发生，