Data from: Sex differences in senescence: the role of intra-sexual competition in early adulthood

Males and females frequently differ in their rates of ageing, but the origins of these differences are poorly understood. Sex differences in senescence have been hypothesized to arise because investment in intra-sexual reproductive competition entails costs to somatic maintenance, leaving the sex that experiences stronger reproductive competition showing higher rates of senescence. However, evidence that sex differences in senescence are attributable to downstream effects of the intensity of intra-sexual reproductive competition experienced during the lifetime remains elusive. Here we show using a 35 year study of wild European badgers (Meles meles), that (i) males show higher body mass senescence rates than females, and (ii) this sex difference is largely attributable to sex-specific downstream effects of the intensity of intra-sexual competition experienced during early adulthood. Our findings provide rare support for the view that somatic maintenance costs arising from intra-sexual competition can cause both individual variation and sex differences in senescence.

雌雄个体的衰老（senescence）速率往往存在差异，但其起源机制迄今尚未得到充分解析。学界此前提出假说，认为衰老的性差异源于同性繁殖竞争（intra-sexual reproductive competition）的投入会以体细胞维持（somatic maintenance）为代价，因此经历更强繁殖竞争的性别，其衰老速率也更快。然而，迄今为止仍缺乏确凿证据，证明衰老的性差异可归因于个体一生中经历的同性繁殖竞争强度所产生的下游效应。本研究基于对野生欧洲獾（Meles meles）长达35年的野外研究，证实了两点：其一，雄性的体重衰老速率显著高于雌性；其二，这类性差异主要源于个体成年早期经历的同性繁殖竞争强度所产生的性别特异性下游效应。本研究结果为‘同性繁殖竞争带来的体细胞维持成本，可同时导致衰老的个体间差异与性差异’这一观点提供了罕见的实证支持。