Data from: Age-specific breeding success in a wild mammalian population: selection, constraint, restraint, and senescence

The Selection, Constraint, Restraint, and Senescence Hypotheses predict how breeding success should vary with age. The Selection Hypothesis predicts between-individual variation arising from quality differences; the other hypotheses predict within-individual variation due to differing skills or physiological condition (Constraint), residual reproductive lifespan (Restraint), or somatic and reproductive investment (Senescence). Studies tend to focus on either the initial increase in breeding success or later decrease; however, both require consideration when unravelling the underlying evolutionary processes. Additionally, few studies present genetic fitness measures, and rarely for both sexes. We therefore test these four hypotheses, which are not mutually exclusive, in a high-density population of European badgers Meles meles. Using an 18-year dataset (including 22 microsatellite loci) we show an initial improvement in breeding success with age, followed by a later and steeper rate of reproductive senescence in males than in females. Breeding success was skewed within age-classes indicating the influence of factors other than age-class. This was partly attributable to selective appearance and disappearance of badgers (Selection Hypothesis). Individuals with a late age of last breeding showed a concave down relationship between breeding success and experience (Constraint Hypothesis). There was no evidence of abrupt terminal effects; rather, individuals showed a concave down relationship between breeding success and residual reproductive lifespan (Restraint Hypothesis), with an interaction with age of first breeding only in females. Our results demonstrate the importance of investigating a comprehensive suite of factors in age-specific breeding success analyses, in both sexes, in order to fully understand evolutionary and population dynamics.选择、约束、限制与衰老假说（Selection, Constraint, Restraint, and Senescence Hypotheses）旨在预测繁殖成功率随年龄的变化规律。其中选择假说（Selection Hypothesis）认为，繁殖成功率的个体间差异源于个体质量的差异；其余三项假说则分别从不同维度解释个体内繁殖成功率的变异：约束假说（Constraint Hypothesis）认为其源于技能或生理状态的差异，限制假说（Restraint Hypothesis）归因于剩余繁殖寿命，而衰老假说（Senescence Hypothesis）则关联体细胞与繁殖投入的权衡。现有相关研究往往仅聚焦于繁殖成功率的早期提升阶段或后期下降阶段，但解析其底层进化机制时，需同时兼顾这两种变化趋势。此外，鲜有研究报告遗传适合度指标，且极少同时涵盖两性个体。因此，我们在高密度种群的欧洲獾（Meles meles）中检验这四项非互斥假说。依托为期18年的数据集（包含22个微卫星位点（microsatellite loci）），我们发现雄性的繁殖成功率随年龄先呈上升趋势，随后出现的生殖衰老速率较雌性更快且更显著。繁殖成功率在各年龄组内呈现偏态分布，提示存在年龄组之外的其他影响因素，这一现象可部分归因于獾个体的选择性出现与消失（选择假说）。末次繁殖年龄较晚的个体，其繁殖成功率与繁殖经验间呈下凹型相关关系（约束假说）。未发现存在显著的突发性终端效应；与之相反，个体繁殖成功率与剩余繁殖寿命间呈下凹型相关关系（限制假说），且仅在雌性个体中，该关系与首次繁殖年龄存在交互效应。本研究结果表明，在针对年龄特异性繁殖成功率的分析中，同时纳入两性个体并全面考量各类影响因素，对于完整解析进化与种群动态至关重要。