Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, Milan, 20133, Italy.
ELKH-PE Evolutionary Ecology Research Group, University of Pannonia, Veszprém, 8210, Hungary.
Evolution. 2022 Nov;76(11):2553-2565. doi: 10.1111/evo.14623. Epub 2022 Oct 3.
Among avian species, the differential cost entailed by either sex in competition for mates has been regarded as the main evolutionary influence on sex differences in mortality rates. However, empirical evidence suggests that sex-biased adult mortality is mainly related to differential energy investment in gamete production, with a greater annual mass devoted to egg production leading to higher female mortality. We explicitly tested the generality of this pattern in a comparative framework. Annual egg production can be relatively large in some species (up to 200% of female body mass) and annual mortality is generally biased toward females. We showed that greater annual egg productivity resulted in higher mortality rates of females relative to males. Mating system was secondarily important, with species in which males were more involved in mating competition having more equal mortality rates between the sexes. However, both traits explained only a limited fraction of the interspecific variation in female-biased mortality. Other traits, such as sexual size dimorphism and parental care, had much weaker influences on female-biased mortality. Our results suggest that both annual mass devoted to gamete production by females and mating system contribute to the evolution of the fundamental life-history trade-off between reproduction and survival in avian taxa.
在鸟类物种中，雄性和雌性在争夺配偶方面的差异成本被认为是导致死亡率性别差异的主要进化影响因素。然而，实证证据表明，性别偏向的成年死亡率主要与配子生产中的能量投入差异有关，雌性每年投入更多的质量用于产卵，导致其死亡率更高。我们在一个比较框架中明确测试了这种模式的普遍性。在某些物种中，每年的产卵量可能相对较大（高达雌性体重的 200%），并且通常雌性的死亡率偏向于更高。我们表明，每年更大的产卵生产力导致雌性的死亡率相对于雄性更高。交配系统是次要重要的，在雄性更多参与交配竞争的物种中，两性之间的死亡率更为平等。然而，这两个特征仅解释了雌性偏向性死亡率的种间变异的有限部分。其他特征，如性二型性和亲代照顾，对雌性偏向性死亡率的影响要弱得多。我们的结果表明，雌性用于配子生产的每年质量和交配系统都有助于在鸟类分类群中繁殖和生存之间的基本生命史权衡的进化。
