Data from: Effects of the group’s mix of sizes and personalities on the emergence of alternative mating systems in water striders

Although much work has analysed how individual behavioural plasticity and adaptations to ecological conditions (e.g. density, sex-ratio, resource distribution) shape mating systems, few studies have assessed the relative importance of multiple factors in explaining why mating systems vary from one sub-population to the next even in the same ecological conditions. Differences among groups in their phenotypic composition, such as their average phenotype, within-group variation in phenotype, or the phenotype of individuals occupying key social roles might shape the mating system emerging at the group level and explain some portion of mating system variability. Here, we take advantage of the mating system flexibility of stream water striders (Aquarius remigis) to investigate how phenotypic composition affects the mating system emerging at the group level. Groups exhibited stable mating systems varying from scramble polygyny with intense sexual conflict, to systems with a clear dominant male guarding a “harem” of females. We found that male size asymmetries and the personality of the largest individuals within groups had important effects on the group’s mating system. The group’s average male and female personality, size, and social plasticity also explained some of the variation in mating systems. Our study is one of the first to quantify significant relationships between group phenotypic composition and mating system variability.尽管已有大量研究探讨了个体行为可塑性与对生态条件（如种群密度、性比、资源分布）的适应性如何塑造交配系统，但鲜有研究评估多重因素的相对重要性，以解释即便在相同生态条件下，交配系统为何在不同亚种群间仍存在差异。不同种群组间的表型组成差异——例如平均表型、组内表型变异，或是占据关键社会角色的个体表型——或可塑造种群组层面显现的交配系统，并部分解释交配系统的变异性。本研究利用溪流尺蝽（Aquarius remigis）的交配系统灵活性，探讨表型组成如何影响种群组层面的交配系统。研究中的种群组呈现出稳定的交配系统谱系：从存在激烈性冲突的掠夺式多配制，到由优势雄性守卫雌性“后宫”的明确交配系统。研究发现，种群组内的雄性体型不对称性，以及体型最大个体的性格特征，对种群组的交配系统具有重要影响。种群组的平均雌雄性格、体型以及社会可塑性，同样可部分解释交配系统的变异。本研究是首批量化种群组表型组成与交配系统变异性之间显著关联的研究之一。