Data from: Induced parental care in a poison frog: a tadpole cross-fostering experiment

Understanding the external stimuli and natural contexts that elicit complex behaviours, such as parental care, is key in linking behavioural mechanisms to their real-life function. Poison frogs provide obligate parental care by shuttling their tadpoles from terrestrial clutches to aquatic nurseries, but little is known about the proximate mechanisms that control these behaviours. In this study, we used Allobates femoralis, a poison frog with predominantly male parental care, to investigate whether tadpole transport can be induced in both sexes by transferring unrelated tadpoles to the backs of adults in the field. Specifically, we asked whether the presence of tadpoles on an adult's back can override the decision-making rules preceding tadpole pick-up and induce the recall of spatial memory necessary for finding tadpole deposition sites. We used telemetry to facilitate accurate tracking of individual frogs and spatial analysis to compare movement trajectories. All tested individuals transported their foster-tadpoles to water pools outside their home area. Contrary to our expectation, we found no sex difference in the likelihood to transport or in the spatial accuracy of finding tadpole deposition sites. We reveal that a stereotypical cascade of parental behaviours that naturally involves sex-specific offspring recognition strategies and the use of spatial memory can be manipulated by experimental placement of unrelated tadpoles on adult frogs. As individuals remained inside their home area when only the jelly from tadpole-containing clutches was brushed on the back, we speculate that tactile rather than chemical stimuli trigger these parental behaviours.

解析可诱发亲本抚育（parental care）等复杂行为的外部刺激与自然情境，是将行为机制与其现实生态功能建立关联的核心所在。箭毒蛙会将蝌蚪从陆地卵团（terrestrial clutches）转移至水生育幼栖息地（aquatic nurseries），以此提供专性亲本抚育（obligate parental care），但目前学界对调控这类行为的近因机制（proximate mechanisms）仍知之甚少。本研究以主要由雄性承担亲本抚育的股腺动趾蛙（Allobates femoralis）为研究对象，通过在野外将非自身后代的蝌蚪转移至成蛙背部，探究是否可在两性个体中诱导出蝌蚪转运行为（tadpole transport）。具体而言，我们旨在探究成蛙背部的蝌蚪存在是否能够打破蝌蚪捡拾前的决策规则，并诱导出寻找蝌蚪投放位点所需的空间记忆（spatial memory）召回过程。本研究借助无线电遥测技术（telemetry）实现对个体蛙的精准追踪，并通过空间分析比对其运动轨迹（movement trajectories）。所有受试个体均将寄养蝌蚪（foster-tadpoles）转运至家域范围（home area）外的积水坑中。与我们的预期相悖的是，无论是转运行为发生概率还是寻找蝌蚪投放位点的空间准确性，均未发现显著的性别差异。本研究证实，自然状态下涉及性别特异性后代识别策略（sex-specific offspring recognition strategies）与空间记忆运用的典型亲本行为级联反应（stereotypical cascade of parental behaviours），可通过在成蛙背部实验性放置非自身后代蝌蚪加以操控。当仅将携带蝌蚪的卵团的卵胶膜（jelly from tadpole-containing clutches）涂抹于成蛙背部时，受试个体仍停留于家域范围内，据此我们推测，触发这类亲本行为的是触觉刺激（tactile stimuli）而非化学刺激（chemical stimuli）。