Evolutionary Ecology Research Group, Hungarian Research Network-University of Pannonia, Veszprém 8200, Hungary.
Behavioural Ecology Research Group, Center for Natural Sciences, University of Pannonia, Veszprém 8200, Hungary.
Proc Natl Acad Sci U S A. 2024 May 28;121(22):e2321294121. doi: 10.1073/pnas.2321294121. Epub 2024 May 21.
Males and females often have different roles in reproduction, although the origin of these differences has remained controversial. Explaining the enigmatic reversed sex roles where males sacrifice their mating potential and provide full parental care is a particularly long-standing challenge in evolutionary biology. While most studies focused on ecological factors as the drivers of sex roles, recent research highlights the significance of social factors such as the adult sex ratio. To disentangle these propositions, here, we investigate the additive and interactive effects of several ecological and social factors on sex role variation using shorebirds (sandpipers, plovers, and allies) as model organisms that provide the full spectrum of sex role variation including some of the best-known examples of sex-role reversal. Our results consistently show that social factors play a prominent role in driving sex roles. Importantly, we show that reversed sex roles are associated with both male-skewed adult sex ratios and high breeding densities. Furthermore, phylogenetic path analyses provide general support for sex ratios driving sex role variations rather than being a consequence of sex roles. Together, these important results open future research directions by showing that different mating opportunities of males and females play a major role in generating the evolutionary diversity of sex roles, mating system, and parental care.
男性和女性在生殖中通常扮演不同的角色，尽管这些差异的起源一直存在争议。解释雄性牺牲交配潜力并提供完全亲代照顾的神秘反转性别角色是进化生物学中一个特别长期存在的挑战。虽然大多数研究将生态因素作为性别角色的驱动因素，但最近的研究强调了社会因素（如成年性别比）的重要性。为了理清这些观点，在这里，我们使用滨鸟（矶鹬、滨鹬和相关鸟类）作为模型生物，调查了几种生态和社会因素对性别角色变化的加性和交互作用，这些模型生物提供了性别角色变化的全貌，包括一些最著名的性别反转例子。我们的研究结果一致表明，社会因素在驱动性别角色方面起着重要作用。重要的是，我们表明，反转的性别角色与雄性偏向的成年性别比和高繁殖密度有关。此外，系统发育路径分析为性别比驱动性别角色变化提供了普遍支持，而不是性别角色的结果。这些重要的结果表明，不同的雌雄两性交配机会在产生性别角色、交配系统和亲代照顾的进化多样性方面发挥了主要作用，为未来的研究指明了方向。
