Data from: Explaining sex differences in lifespan in terms of optimal energy allocation in the baboon

We provide a quantitative test of the hypothesis that sex role specialisation may account for sex differences in lifespan in baboons if such specialisation causes the dependency of fitness upon longevity, and consequently the optimal resolution to an energetic trade-off between somatic maintenance and other physiological functions, to differ between males and females. We present a model in which females provide all offspring care and males compete for access to reproductive females and in which the partitioning of available energy between the competing fitness-enhancing functions of growth, maintenance and reproduction is modelled as a dynamic behavioural game, with the optimal decision for each individual depending upon his/her state and the behaviour of other members of the population. Our model replicates the sexual dimorphism in body size and sex differences in longevity and reproductive scheduling seen in natural populations of baboons. We show that this outcome is generally robust to perturbations in model parameters, an important finding given the same behaviour is seen across multiple populations and species in the wild. This supports the idea that sex differences in longevity result from differences in the value of somatic maintenance relative to other fitness-enhancing functions in keeping with the disposable soma theory.

本研究针对如下假说开展定量检验：若性角色特化（sex role specialisation）会导致适应度（fitness）对寿命的依赖发生改变，且进而使得体细胞维持（somatic maintenance）与其他生理功能间的能量权衡最优解在雌雄个体间存在差异，则该特化可解释狒狒寿命的性别差异。本研究构建了如下模型：雌性个体全权承担育幼职责，雄性个体则竞争与育龄雌性的交配权；同时将生长、维持与繁殖这三类相互竞争的提升适应度功能间的可用能量分配，建模为动态行为博弈，每个个体的最优决策取决于其自身状态与种群内其他成员的行为。本模型复现了狒狒自然种群中观察到的体型性二态性、寿命性别差异以及繁殖时序的性别差异。研究表明，该结果对模型参数的扰动普遍具有鲁棒性；鉴于野生环境中多个种群与物种均存在同类行为，这一发现具有重要意义。这一结果支持如下观点：寿命的性别差异源于体细胞维持相较于其他提升适应度功能的价值差异，这与体细胞可弃理论（disposable soma theory）的核心主张一致。