Evolving associations: cooperation and conflict within and between species

合作是进化论中的一个难题，因为合作者承担着造福他人的成本。这导致了一个社会两难境地，每个人都更好地合作，但个人却受到搭便车的诱惑，损害了所有人的利益。进化博弈论，EGT，一直是推动物种内相互作用理论的工具，特别是对于理解合作。如果个人行动给另一个物种带来好处，合作的问题就会加剧。然而，跨物种关联在自然界中无处不在，其影响范围广泛，从保护生物学到农业和健康：珊瑚礁的生存取决于珊瑚和藻类之间的关联，许多植物依赖传粉者或固氮菌，而寄生蜂关联可以控制害虫，人类健康依赖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，但令人惊讶的是，它在过去很少受到关注。这一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、重复互动、种群结构或外部选择来减少作弊的机制。新的动态方面产生于相关物种之间在竞争、遗传、时间尺度、个体大小和生态方面的差异。严格的机械分类有助于组织和推进自然界中看似无穷无尽的跨物种联系的理论。融合了EGT和自适应动力学(AD)，有望为关联的进化提供新的见解。理论有助于描绘有利于形成和塑造联想的条件，例如水平和垂直共生传播在防止欺骗、驯服寄生虫方面的作用，或促进从寄生到互惠和兼性到义务联想的转变。对于联合的出现，考虑了两条特别有希望的进化路径：一个物种对另一个物种的栽培--实际上看起来可能是复杂的剥削形式--或者是物种内的专业化和分工，这变成了一种推动物种形成的选择性力量，并有可能在协会一级引入选择。在文化背景下，社会分层的出现类似于物种之间的竞争，主要是在阶层内部，但在阶层之间相互作用。社会等级、机构和政府的演变使团体能够通过协调一致的努力来更有效地运作，以造福于所有人。然而，在许多社会中，腐败对社会机构构成重大挑战。这一理论有助于确定防止阶层之间的互惠关系退化为专制敲诈勒索的措施。

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.