Experimental evidence in a poison frog model suggests that tadpole transport on the dorsum may affects warning signal effectiveness in poison frogs

Aposematism is an anti-predator strategy where predators learn to associate the warning signal on prey with an unpleasant experience, and consequently, avoid attacking similar prey in the future. Conspicuous coloration in poison frogs (Dendrobatidae) is considered a warning signal. During parental care, parents transport their tadpoles on the dorsum, which could alter the detectability and recognition of such warning coloration by visually oriented predators. We tested this hypothesis using domestic chicks trained to avoid and discriminate between printed frog models with and without conspicuous-warning coloration. We tested whether the chicks recognized the warning coloration on printed frog models that varied in the quantity of tadpoles on the dorsum. Chicks first attacked frog models without warning coloration, whether they had tadpoles on the dorsum or not. In contrast, frog models with warning coloration were attacked last by chicks. Moreover, the frog models with warning coloration and without tadpoles experienced a lower risk of attack by chicks than similar frog models with tadpoles. However, aposematic frog models maintained the warning function of conspicuous coloration if it was located on parts of the parent's body that are not covered by the tadpoles when transported. Our results suggest that tadpoles on the dorsum of parents might compromise the effectiveness of the warning signal display in poison frogs increasing the risk of attack by visually oriented predators.