Data from: Sexual size dimorphism is not associated with the evolution of parental care in frogs

Sex differences in parental care are thought to arise from differential selection on the sexes. Sexual dimorphism, including sexual size dimorphism (SSD), is often used as a proxy for sexual selection on males. Some studies have found an association between male-biased SSD (i.e., males larger than females) and the loss of paternal care. While the relationship between sexual selection on males and parental care evolution has been studied extensively, the relationship between female-biased SSD (i.e., females larger than males) and the evolution of parental care has received very little attention. Thus, we have little knowledge of whether female-biased SSD coevolves with parental care. In species displaying female-biased SSD, we might expect dimorphism to be associated with the evolution of paternal care or perhaps the loss of maternal care. Here, drawing on data for 99 extant frog species, we use comparative methods to evaluate how parental care and female-biased SSD have evolved over time. Generally, we find no significant correlation between the evolution of parental care and female-biased SSD in frogs. This suggests that differential selection on body size between the sexes is unlikely to have driven the evolution of parental care in these clades and questions whether we should expect sexual dimorphism to exhibit a general relationship with the evolution of sex differences in parental care.亲本抚育的性别差异被认为源于不同性别的差异化选择。包括性体型二态性（sexual size dimorphism, SSD）在内的性二态性，常被用作衡量雄性性选择强度的替代指标。已有部分研究发现，雄性偏倚性体型二态性（即雄性体型大于雌性）与父本抚育行为的丢失存在关联。尽管针对雄性性选择与亲本抚育演化之间的关联已得到广泛研究，但雌性偏倚性体型二态性（即雌性体型大于雄性）与亲本抚育演化之间的关系却极少受到关注。因此，我们对雌性偏倚性体型二态性是否与亲本抚育协同演化仍知之甚少。在展现雌性偏倚性体型二态性的物种中，我们或许可以推测，该二态性或与父本抚育的演化相关，亦或与母本抚育的丢失存在关联。本研究依托99种现存蛙类的数据，采用比较分析方法探究亲本抚育与雌性偏倚性体型二态性随时间的演化模式。总体而言，我们未在蛙类中发现亲本抚育演化与雌性偏倚性体型二态性之间存在显著相关性。这一结果表明，两性间体型的差异化选择不太可能驱动这些支系的亲本抚育演化，同时也对“性二态性与亲本抚育的性别差异演化存在普遍关联”这一认知提出了质疑。