Maturation (the age when organisms are physiologically capable of breeding) is one of the major life history traits that have pervasive implications for reproductive strategies, fitness, and population growth. Sex differences in maturation are common in nature, although the causes of such differences are not understood. Fisher and Lack proposed that delayed maturation in males is expected when males are under intense sexual selection, but their proposition has never been tested across a wide range of taxa. By using phylogenetic comparative analyses and the most comprehensive dataset to date, including 201 species from 59 avian families, we show that intense sexual selection on males (as indicated by polygamous mating and male‐skewed sexual size dimorphism) correlates with delayed maturation. We also show that the adult sex ratio (ASR), an indicator of the social environment, is associated with sex‐specific maturation because in species with a female‐skewed ASR, males experience later maturation. Phylogenetic path analyses suggest that adult sex ratio drives interspecific changes in the intensity of sexual selection which, in turn, influences maturation. These results are robust to alternative phylogenetic hypotheses and to potential life‐history confounds, and they provide the first comprehensive support of Fisher's and Lack's propositions. Importantly, our work suggests that both social environment and mate competition influence the evolution of a major life history trait, maturation.

中文翻译：

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成熟期的性别差异与鸟类的性别选择和成年性别比有关

成熟（生物体具有生理繁殖能力的年龄）是生命史上的主要特征之一，对生殖策略，适应性和人口增长具有普遍意义。性别上的成熟差异自然很常见，尽管这种差异的原因尚不清楚。Fisher和Lack提出，当雄性处于强烈的性选择之下时，雄性的延迟成熟是可以预期的，但是他们的主张从未在广泛的分类单元中得到检验。通过使用系统发育比较分析和迄今为止最全面的数据集，包括来自59个禽类的201个种，我们显示，雄性的强烈性选择（如一夫多妻制和雄性性别尺寸二态性表明）与延迟成熟相关。我们还表明，成人性别比（ASR）社会环境的一个指标与特定性别的成熟度相关，因为在具有女性偏斜ASR的物种中，男性经历的则是较晚的成熟。系统发育路径分析表明，成年性别比驱动性别选择强度的种间变化，进而影响成熟。这些结果对于其他系统发育假说和潜在的生命史混杂因素均是可靠的，并且它们为Fisher和Lack的命题提供了第一个全面的支持。重要的是，我们的工作表明，社会环境和伴侣竞争都会影响主要生活史特征成熟的演变。系统发育路径分析表明，成年性别比驱动性别选择强度的种间变化，进而影响成熟度。这些结果对于其他系统发育假说和潜在的生命史混杂因素均是可靠的，并且它们为Fisher和Lack的命题提供了第一个全面的支持。重要的是，我们的工作表明，社会环境和伴侣竞争都会影响主要生活史特征成熟的演变。系统发育路径分析表明，成年性别比驱动性别选择强度的种间变化，进而影响成熟度。这些结果对于其他系统发育假说和潜在的生命史混杂因素均是可靠的，并且它们为Fisher和Lack的命题提供了第一个全面的支持。重要的是，我们的工作表明，社会环境和伴侣竞争都会影响主要生活史特征成熟的演变。