Evolving associations: cooperation and conflict within and between species

合作是进化理论中的一个难题，因为合作者要为他人的利益付出代价。这导致了一种社会困境，即每个人都通过合作变得更好，但个人却倾向于搭便车，损害所有人的利益。进化博弈论（EGT）在推进物种间相互作用理论和理解合作方面发挥了重要作用。如果个体行为给其他物种带来利益，合作问题就会加剧。然而，跨物种联系在自然界中无处不在，具有从保护生物学到农业和健康的广泛影响：珊瑚礁的生存取决于珊瑚和藻类之间的联系，许多植物依赖于传粉媒介或固氮细菌，而寄生性联系可以控制害虫，人类健康取决于我们相关的微生物群。EGT非常适合于模拟更具挑战性和多样化的物种间相互作用，但在过去却很少受到关注。该建议利用我们在物种内进化方面的专业知识来对比、比较和探索物种间的相互作用：相似性包括通过惩罚、重复相互作用、种群结构或外部选择来减少欺骗的机制。在竞争、遗传、时间尺度、个体大小和生态等方面的差异产生了新的动态方面。严格的机械分类有助于组织和推进自然界中似乎无穷无尽的跨物种关联的理论。将EGT和适应性动力学（AD）结合起来，有望对关联的进化产生新的见解。理论有助于描述有利于形成和形成关联的条件，例如水平和垂直共生传播的作用，以防止欺骗，驯服寄生虫，或促进从寄生到互惠和兼性到义务关联的转变。对于结合力的出现，人们认为有两种特别有希望的进化途径：一种是一个物种被另一个物种培育——看起来像是互惠的结合力，实际上可能是复杂的剥削形式——或者是物种内部的专业化和劳动分工，这变成了一种推动物种形成的选择力量，并有可能在结合力的层面上引入选择。在文化背景下，社会分层的出现类似于主要在阶层内部竞争而在阶层之间相互作用的物种关联。社会等级制度、制度和政府的演变使群体能够通过协调一致的努力更有效地发挥作用，造福所有人。然而，在许多社会中，腐败对社会制度构成重大挑战。理论有助于确定防止各阶层之间互惠关系退化为专制勒索的措施。

Cooperation is a conundrum in evolutionary theory because cooperators bear costs to benefit others. This results in a social dilemma where everyone is better off cooperating but individuals are tempted to free ride to the detriment of all. Evolutionary game theory, EGT, has been instrumental for advancing the theory of intra-species interactions and for understanding cooperation, in particular. The problem of cooperation is exacerbated if individual actions bestow benefits to another species. Nevertheless, cross-species associations are ubiquitous in nature with vast implications ranging from conservation biology to agriculture and health: the survival of coral reefs hinges on associations between corals and algae, many plants rely on pollinators or on nitrogen fixing bacteria, while parasitoid associations can control pests, and human health depends on our associated microbiome. EGT is ideally suited to model the significantly more challenging and variegated inter-species interactions but received surprisingly little attention in the past. This proposal leverages our expertise in intra-species evolution to contrast, compare and explore inter-species interactions: similarities include mechanisms to reduce cheating through punishment, repeated interactions, population structures or outside options. Novel dynamical aspects arise through differences in competition, inheritance, timescales, individual size and ecology between the associated species. A rigorous mechanistic classification helps to organize and advance the theory of the seemingly endless varieties of cross-species associations in nature. Amalgamating EGT and adaptive dynamics, AD, promises novel insights into the evolution of associations. Theory helps to delineate conditions conducive to form and shape associations, such as the role of horizontal and vertical symbiont transmission to prevent cheating, tame parasites, or to promote transitions from parasitic to mutualistic and facultative to obligate associations. For the emergence of associations two particularly promising evolutionary pathways are considered: the cultivation of one species by another - what appears as mutualistic associations may, in effect, be sophisticated forms of exploitation - or, specialization and division of labour within species, which turns into a selective force that drives speciation and has the potential to introduce selection on the level of associations. In cultural settings the emergence of social stratification resembles species associations with competition predominantly within but interactions between strata. The evolution of social hierarchies, institutions and governments enables groups to function more efficiently by coordinating concerted efforts for the benefit of all. However, in many societies corruption poses a major challenge to social institutions. Theory helps to identify measures to prevent the degradation of mutualistic associations between strata into despotic extortion.