The smell of success: choice of larval rearing sites by means of chemical cues in a Peruvian poison frog

Parental care is a common strategy among vertebrates to ensure successful reproduction. Anuran amphibians have evolved a remarkable diversity of reproductive methods including advanced levels of parental care. Among the most derived strategies are those of the Neotropical poison frogs (Dendrobatidae). These amphibians exhibit a wide array of behavioural traits such as egg guarding, larval transport by parental frogs and larval feeding with trophic (unfertilized) eggs. Ranitomeya variabilis from the upper Amazon basin in Peru deposits both eggs and tadpoles in phytotelmata. The exploitation of these small pools is advantageous as it lowers the risk of predation, but it is more costly because of limited resource availability. Additionally, poison frog larvae are often cannibalistic, so the identification and avoidance of conspecifics represents an adaptive behaviour for these amphibians. While studies have shown that poison frogs actively avoid depositing with conspecifics, the mechanism for assessing pool quality remains unknown. In field experiments, we found that parental R. variabilis frogs used chemical cues to recognize the presence of tadpoles in phytotelmata. Furthermore, they distinguished between cannibalistic and noncannibalistic tadpoles, a behaviour that supports the survival of their own offspring.