Data from: Patterns of parental care in Neotropical glassfrogs: fieldwork alters hypotheses of sex-role evolution

Many animals provide parental care to offspring. Parental sex-roles vary extensively across taxa, and such patterns are considered well documented. However, information on amphibians is lacking relative to other vertebrate groups. We combine natural history observations with functional and historical analyses to examine the evolution of egg care in glassfrogs (Centrolenidae). Parental care was considered rare and predominately provided by males. Our field observations of 40 species revealed that care occurs throughout the family, and the caregiving sex changes across lineages. We discovered that a brief period of maternal care is widespread and occurs in species previously thought to lack care. Using a combination of female-removal experiments, prey-choice tests with egg-eating katydids, and parental disturbance-tolerance assays, we confirm the adaptive benefits of short-term maternal care in wild Cochranella granulosa and Teratohyla pulverata. To examine historical transitions between caregiving sexes, we assembled a molecular phylogeny and estimated ancestral care states using our data and the literature. We assessed patterns indicative of sex-specific constraints by testing whether transitions between the sexes are associated with changes in care levels. Our analyses support that male-only care evolved 2–3 times from female-only care, and this change is associated with substantial increases in care levels—a pattern supporting the hypothesis that male-only care evolved via constraints on maternal expenditure. Many groups of amphibians remain poorly studied, with emerging evidence indicating that care patterns are more diverse than currently appreciated. Natural history remains fundamental to uncovering this diversity and generating testable hypotheses of sex-role evolution.

诸多动物均会为后代提供亲代抚育（parental care）。亲代抚育的性别角色在不同生物类群（taxa）中差异显著，此类模式既往被认为已有充分的文献记载。然而相较于其他脊椎动物类群，两栖动物的相关研究资料仍较为匮乏。本研究结合自然史观测、功能分析与历史演化分析，针对瞻星蛙科（Centrolenidae）玻璃蛙的卵抚育演化展开研究。此前学界普遍认为，亲代抚育在该类群中较为罕见，且主要由雄性个体承担。我们对40个物种的野外观测结果显示，抚育行为在整个瞻星蛙科中普遍存在，且抚育的承担性别在不同演化支（lineages）间存在分化。我们发现，短暂的雌性抚育行为分布广泛，甚至在此前被认为不存在抚育行为的物种中也存在此类现象。我们通过雌性移除实验（female-removal experiments）、针对食卵螽斯（egg-eating katydids）的猎物选择试验，以及亲代耐受干扰试验（parental disturbance-tolerance assays），证实了野生粒瞻星蛙（Cochranella granulosa）与粉瞻星蛙（Teratohyla pulverata）的短期雌性抚育具有适应性收益。为探究抚育承担性别间的历史演化转变，我们构建了分子系统发育树，并结合本研究数据与已发表文献，估算了该类群的祖先抚育状态。我们通过检验抚育性别转换是否与抚育强度变化相关，评估了性特异性约束的相关模式。分析结果表明，仅雄性抚育曾从仅雌性抚育演化而来2至3次，且这一演化转变伴随抚育强度的显著提升——这一结果支持了“仅雄性抚育通过对雌性抚育成本的约束演化而来”的假说。目前仍有大量两栖动物类群未得到充分研究，而新兴证据表明，两栖动物的抚育模式多样性远超当前学界的认知。自然史研究仍是揭示此类多样性、提出可验证的性别角色演化假说的核心基础。