Data from: A key ecological trait drove the evolution of biparental care and monogamy in an amphibian

Linking specific ecological factors to the evolution of parental care pattern and mating system is a difficult task of key importance. We provide evidence from comparative analyses that an ecological factor (breeding pool size) is associated with the evolution of parental care across all frogs. We further show that the most intensive form of parental care (trophic egg feeding) evolved in concert with the use of small pools for tadpole deposition and that egg feeding was associated with the evolution of biparental care. Previous research on two Peruvian poison frogs (Ranitomeya imitator and Ranitomeya variabilis) revealed similar life histories, with the exception of breeding pool size. This key ecological difference led to divergence in parental care patterns and mating systems. We present ecological field experiments that demonstrate that biparental care is essential to tadpole survival in small (but not large) pools. Field observations demonstrate social monogamy in R. imitator, the species that uses small pools. Molecular analyses demonstrate genetic monogamy in R. imitator, the first example of genetic monogamy in an amphibian. In total, this evidence constitutes the most complete documentation to date that a single ecological factor drove the evolution of biparental care and genetic and social monogamy in an animal.

将特定生态因子与育幼模式演化及交配系统相联系，是一项兼具关键意义与挑战性的研究课题。本研究通过比较分析提供实证，表明生态因子繁殖池大小（breeding pool size）与所有蛙类的育幼演化存在显著关联。进一步研究显示，强度最高的育幼形式——营养卵哺育（trophic egg feeding）——与利用小型水池开展蝌蚪投放（tadpole deposition）的行为协同演化，且营养卵哺育与双亲育幼（biparental care）的演化存在密切相关性。此前针对两种秘鲁箭毒蛙——模仿箭毒蛙（Ranitomeya imitator）与可变箭毒蛙（Ranitomeya variabilis）——的研究显示，二者的生活史特征高度相似，仅繁殖池大小存在关键差异。这一生态差异最终导致了育幼模式与交配系统的分化。本研究通过野外生态实验证实，在小型水池（而非大型水池）中，双亲育幼对蝌蚪存活至关重要。野外观察表明，使用小型水池的模仿箭毒蛙（R. imitator）存在社会单配制（social monogamy）；分子分析则进一步证实该物种存在遗传单配制（genetic monogamy），这是两栖动物中首例被证实的遗传单配制案例。综上，本研究提供了截至目前最为完整的实证链条，证明单一生态因子可驱动动物双亲育幼以及社会与遗传单配制的演化。