Data from: Concessions, lifetime fitness consequences and the evolution of coalitionary behavior

The relationship between the costs of coalitionary behavior and the evolution of such behavior has not been closely examined by theoretical studies. Here, we create a set of life-history models for species whose coalitionary behavior is genetically determined to investigate how different types of costs afflicted upon members of failed coalitions, in terms of survival, fecundity, and social rank, may influence the nature of coalitionary behavior that emerges at evolutionary equilibrium. We also extend previous theory by examining the coevolution between coalitionary behavior and concessions granted by dominant individuals to prevent dominants from being targeted by coalitions. We show that species that form coalitions to contest social rank evolve to regularly form bridging coalitions under a vast majority of social and ecological settings, whereas species that contest fecundity form all-up coalitions under most conditions. Further, dominant individuals concede resources to subordinates to prevent coalitionary attacks only in very few circumstances, and these concessions occur only to ensure another individual is a more attractive coalition target. We compare and contrast results to empirical data to provide an evolutionary context for commonly observed coalitionary behaviors in the animal kingdom.

联盟行为（coalitionary behavior）的成本与该行为演化之间的关联，尚未得到理论研究的细致探讨。为此，我们针对联盟行为由遗传决定的物种构建了一系列生活史模型，以探究失败联盟成员所承受的、基于存活率、繁殖力与社会地位维度的不同类型成本，会如何影响演化均衡状态下出现的联盟行为特征。此外，我们通过探究联盟行为与优势个体为避免自身成为联盟攻击目标而做出的让步之间的协同演化关系，拓展了既有理论框架。研究结果表明，为争夺社会地位而结成联盟的物种，在绝大多数社会与生态环境下会演化出常态化形成搭桥联盟的特征；而以争夺繁殖力为目标的物种，在多数条件下则会形成全成员联盟。进一步而言，优势个体仅在极少数情形下会向从属个体让渡资源以避免联盟攻击，且此类让步仅发生在确保其他个体成为更具吸引力的联盟攻击目标之时。我们将研究结果与实证数据进行对比分析，为动物界中普遍观测到的联盟行为提供演化层面的理论语境。