Out in the wind: wiping behaviour in the leaf-frog Pithecopus ayeaye, and first evidence of bladder-filling behaviour in the genus

The colonisation of land by tetrapods marked a critical event in animal evolution, introducing desiccation risk as a pivotal selective pressure that influenced physiological, behavioural and morphological adaptations. Leaf-frogs (Phyllomedusinae) exhibit adaptations to mitigate water loss, but limited observations hinder our understanding of these behaviours' prevalence and consequently their evolutionary history. Here, we present novel observations of wiping and bladder-filling behaviours in the leaf-frog Pithecopus ayeaye. Wiping behaviour was recorded in both natural and captive settings, when frogs used their fore and hindlimbs to spread lipidic substances across the skin. Furthermore, we observed bladder-filling behaviour for the first time in this derived Phyllomedusinae genus. Our findings challenge existing paradigms regarding the evolution of these traits and emphasise the need for comprehensive studies across phyllomedusine genera to elucidate their phylogenetic distribution and adaptive significance. Keywords: arboreal reproduction, Hylidae, monkey frogs, Neotropics, water loss mitigation