Biparental care is rare in amphibians, and evidence for pair-bonding between mates has only been found in a few species, one of which is the mimic poison frog, Ranitomeya imitator. A male and female will defend tightly overlapping territories, and cooperate to place and nurture tadpoles in tiny pools that form in plants (phytotelmata). Males carry tadpoles from clutches to the pools, and then periodically lead the female to the pool, where the female will lay trophic eggs that the tadpole depends on for growth and development, over the course of several months. Interactions between mates frequently involve acoustic signals from males to females, such as males calling to females as they guide them to pools. Podraza et al. (2024) set out to determine if female mimic poison frogs show a preference for the calls of their pair-bonded mate, as might be expected in monogamous and cooperative biparental care over long periods. They used male advertisement calls, as previous research had demonstrated that these calls show substantial variation between individuals, but minimal variation within individuals. The researchers set up arenas with speakers on each end and tested the females by playing male calls from one end and nothing from the other (one choice test), or by playing calls of the pair-bonded partner from one end and a stranger from the other (two-choice tests). In the second test, they tested two types of pair-bonded females, with and without a current clutch of eggs with their partner. Virgin females showed a clear preference to approach and remain near the side with male calls, confirming that females are indeed attracted to such calls. They did not, however, show a preference for any individual male calls, relative to those of other males. In the two-choice tests, females spent significantly more time on the side of the arena with the calls from their mates. Further, females actively involved in parental care responded to their mate’s call more quickly than females who were not currently engaged in parental care. This study provides important experimental evidence regarding the mechanisms underlying pair-bonding in this species.

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