SSA: The evolution of cooperation in an arid-zone bird: bet-hedging, plasticity and constraints

解释合作（以牺牲自己为代价造福他人的行为）的进化是进化和机械生物学的一个关键挑战。虽然人们早就认识到，合作行为可能通过提高相关繁殖者的繁殖成功率而间接地给行为者带来健康益处，但该领域的最新进展强调了在实践中验证这一观点的几个潜在问题。首先，合作行为实际上可能通过压缩相关繁殖者繁殖成功的差异而产生间接的适应性利益。其次，合作行为对相关母亲的繁殖成功的影响可能被母亲对合作者的存在的先发制人的反应所掩盖（例如，当母亲预期他们的后代会得到产后合作照顾时，她们可能会减少对后代的产前投资）。第三，被研究得最充分的动物合作形式（同种亲代照料；为其他动物的后代提供照料）的进化可能受到亲代照料的遗传相关性的限制。在这篇论文中，我们利用来自野生喀拉哈里织蜘蛛社会的长期生活史和高密度基因组数据，为这些现象提供了迄今为止最有力的支持，揭示了它们在塑造合作进化中的潜在重要性。

Explaining the evolution of cooperation (behaviour that benefits others at a cost to self) is a key challenge in evolutionary and mechanistic biology. While it has long been recognised that cooperative behaviour may yield indirect fitness benefits to actors by increasing the reproductive success of related breeders, recent advances in the field have highlighted several potential complications with testing this idea in practice. First, cooperative behaviour may actually yield indirect fitness benefits by compressing variance in the reproductive success of related breeders. Second, the effects of cooperative behaviour on the reproductive success of related mothers may be shrouded by pre-emptive maternal responses to the presence of co-operators (e.g. mothers may reduce their pre-natal investment in offspring when they anticipate receiving cooperative post-natal care for their young). Third, the evolution of the best-studied form of animal cooperation (alloparental care; the provision of care to the offspring of others) could be constrained by genetic correlations with parental care. In this thesis we utilise long-term life-history and high density genomic data from wild Kalahari sparrow-weaver societies to provide the strongest support to date for each of these phenomena, shedding new light on their potential importance in shaping the evolution of cooperation.