Partner cues and individual variation underlie sex-reversed parental care in poison frogs

We enlist a biparental frog (Ranitomeya imitator) with flexible sex-reversal of parental care to investigate the extrinsic and intrinsic mechanisms underpinning parental decisions. Using mate removal experiments in the laboratory, we show that members of the primary caregiving sex (males) show less variation than the flexible sex (females) in their propensity to provide care, and that care propensity in females is affected by extrinsic partner cues (i.e., visual and acoustic stimuli) as well as individual variability. To investigate the underpinnings of differences in care propensity, we sequenced RNA from whole brains of transporting and non-transporting frogs of both sexes. While actively caregiving females showed minimal differential gene expression compared to actively caregiving males, females that failed to provide care showed distinct patterns of gene expression.