The Evolution of Sex Differences in Mammalian Social Life Histories

了解为什么长寿的社会性哺乳动物的社会行为和生活史在性别之间存在差异，有时达到极端程度，是生物学，医学和社会科学的一个关键目标。我们认为，在整个生命周期中，男性和女性如何与相关个体互动的性别差异是推动社会行为和生活史中性别差异演变的主要力量。在社会物种中，相关的个体（亲属）通常生活在紧密的家庭群体中，个体可以通过他们的行为（合作和竞争）和生殖决定（如果个体繁殖，它将使用可能对亲属的生存和生殖成功产生负面影响的资源）来影响亲属的生存和生殖成功。亲属之间的这种互动是一种强大的进化力量，个体通过增加亲属的生存和繁殖成功率而获得间接利益（通过与亲属共享的基因）。例如，亲属选择可以有利于提高亲属繁殖成功率的个人策略，即使这会以个人的生存和繁殖成功为代价。亲缘选择塑造进化的机会取决于相关个体如何以及何时相互作用。我们的试点工作表明，在许多物种中，男性和女性经历了非常不同的模式，在他们的生命周期（亲属关系动态），由于模式的传播和交配。例如，对于一些物种，如虎鲸，随着年龄的增长，雌性与当地群体的关系越来越密切，而雄性则相反，关系变得越来越少。我们假设，在亲属动态的性别差异将是一个主要的力量，推动性别差异的演变，在（一）社会行为和（二）生活史。我们将使用理论建模和经验数据分析相结合的方法，确定亲属关系动态在推动社会行为和生活史演变中性别差异演变中的作用。我们将开发一个一般理论的亲属关系动态和开发新的模型来预测双方的模式亲属关系动态和他们的后果在男性和女性的社会生活史的演变。我们的模型将预测社会群体中的帮助和伤害模式，包括行为特征（合作和冲突）和生殖特征（例如第一次或最后一次生殖的年龄）。我们将通过收集关于使用无人驾驶飞行器（无人机）在居民虎鲸中帮助（例如保姆和食物共享）和伤害（攻击）模式的新数据，对我们新理论的行为预测进行首次测试。居民虎鲸非常适合测试模型的行为预测-它们在亲属关系动态中具有极端的性别差异，并且在生活史中具有无法解释的性别差异。我们将测试的生活史预测的理论框架，通过比较模式的亲属关系动态和性别差异的生活史进化（如增长模式，年龄在第一次繁殖，年龄在最后繁殖，生殖投资和寿命）在社会哺乳动物，这将使我们能够确定的作用，亲属关系动态驱动的生活史进化和性别之间的生活史的分歧。

Understanding why social behaviour and life histories have diverged between the sexes in long-lived social mammals, sometimes to an extreme degree, is a key objective in the biological, medical and social sciences. We propose that differences between the sexes in how males and females interact with related individuals across the lifespan are a major force driving the evolution of sex differences in both social behaviour and life history. In social species related individuals (kin) often live together in close knit family groups and individuals can influence the survival and reproductive success of their relatives both by their behaviour (cooperative and competitive) and reproductive decisions (if an individual reproduces it will use resources that may negatively impact on the survival and reproductive success of kin). Such interactions between kin are a strong evolutionary force, with individuals gaining indirect benefits (through the genes they share with relatives) by increasing the survival and reproductive success of their kin. For example, kin selection can favour individual strategies that increase the reproductive success of kin, even if this comes at a cost to an individual's survival and reproductive success. The opportunity for evolution to be shaped by kin selection is dependent on how and when related individuals interact. Our pilot work suggests that in many species males and females experience very different patterns of local relatedness across their lifespans (kinship dynamics) due to patterns of dispersal and mating. For example, for some species such as killer whales, females become more related to their local group with age whereas males, in contrast, become less related. We hypothesise that sex differences in kinship dynamics will be a major force driving the evolution of sex differences in both (i) social behaviour and (ii) life history. We will determine the role of kinship dynamics in driving the evolution of sex differences in social behaviour and life history evolution using a combination of theoretical modelling and empirical data analysis. We will develop a general theory of kinship dynamics and develop new models to predict both the patterns of kinship dynamics and their consequences for the evolution of social life histories in both males and females. Our model will make predictions for patterns of helping and harming in social groups including both behavioural traits (cooperation and conflict) and reproductive traits (e.g. age at first or last reproduction). We will provide the first test of the behavioural predictions of our new theory by collecting new data on patterns of helping (e.g. babysitting and food sharing) and harming (aggression) in resident killer whales using unmanned aerial vehicles (drones). Resident killer whales are ideally suited to testing the behavioural predictions of the model - they have extreme sex differences in kinship dynamics and have unexplained sex differences in life history. We will test the life history predictions of the theoretical framework by comparing patterns of kinship dynamics and sex differences in life history evolution (e.g. patterns of growth, age at first reproduction, age at last reproduction, reproductive investment and longevity) across social mammals which will allow us to determine the role of kinship dynamics in driving life history evolution and the divergence of life histories between the sexes.