Data from: Strong male/male competition allows for nonchoosy females: high levels of polygynandry in a territorial frog with paternal care

Our knowledge about genetic mating systems and the underlying causes for and consequences of variation in reproductive success has substantially improved in recent years. When linked to longitudinal population studies, cross-generational pedigrees across wild populations can help answer a wide suite of questions in ecology and evolutionary biology. We used microsatellite markers and exhaustive sampling of two successive adult generations to obtain population-wide estimates of individual reproductive output of males and females in a natural population of the Neotropical frog Allobates femoralis (Aromobatidae), a pan-Amazonian species that features prolonged iteroparous breeding, male territoriality, and male parental care. Parentage analysis revealed a polygynandrous mating system in which high proportions of males (35.5%) and females (56.0%) produced progeny that survived until adulthood. Despite contrasting reproductive strategies, successfully reproducing males and females had similar numbers of mating partners that sired the adult progeny (both sexes: median 2; range 1–6); the numbers of their offspring that reached adulthood were also similar (both sexes: median 2; range 1–8). Measures of reproductive skew indicate selection on males only for their opportunity to breed. Reproductive success was significantly higher in territorial than non-territorial males, but unrelated to territory size in males or to body size in both sexes. We hypothesise that female polyandry in this species has evolved due to enhanced offspring survival when paternal care is allocated to multiple partners.近年来，学界对遗传交配系统，以及繁殖成功变异的内在成因与后续效应的认知已得到显著提升。若结合纵向种群研究（longitudinal population studies）开展，野生种群的跨代谱系分析可助力解答生态学与进化生物学领域的诸多科学问题。本研究以新热带蛙类丛棘箭毒蛙（Allobates femoralis，芳香蛙科Aromobatidae）——一种泛亚马逊分布、兼具长期迭代繁殖、雄性领域行为与雄性育幼特征的物种——的自然种群为研究对象，通过微卫星标记（microsatellite markers）与对连续两个世代成体的穷尽式采样，获取了该种群雌雄个体繁殖产出的全种群水平评估数据。父权分析（parentage analysis）显示，该物种存在多配混交交配系统：35.5%的雄性与56.0%的雌性均可成功产生存活至成体的后代。尽管雌雄繁殖策略存在显著差异，但成功繁殖的雌雄个体所拥有的、可产生成年后代的配偶数量并无显著差异（两性中位数均为2，范围1~6）；且二者达到成年的后代数量也较为相近（两性中位数均为2，范围1~8）。繁殖偏倚（reproductive skew）的相关指标显示，仅在繁殖机会层面存在对雄性的选择压力。具有领域性的雄性的繁殖成功率显著高于非领域性雄性，但雄性的繁殖成功率与领域面积无关，且雌雄个体的繁殖成功率均与其体型大小无关联。本研究提出假说：该物种的雌性一妻多夫（polyandry）行为之所以演化而来，是因为当雄性可向多个配偶提供育幼照料时，后代的存活概率会得到提升。