Correlated evolution of parental care with dichromatism, colour, and patterns in anurans

Abstract

Parental care is remarkably and widespread among vertebrates because of its clear fitness benefits. Caring however incurs energetic and ecological costs including increasing predation risk. Anurans have diverse forms of parental care, and we test whether the evolution of care is associated with morphology that minimizes predation risk. Specifically, we determine whether dichromatism, specific colours gradients, and patterns that enhance crypticity are associated with anurans that also evolve parental care. From our phylogenetic comparative analyses of 988 anurans distributed globally, we find that parental care is less likely to evolve in species with dichromatism. Contrary to our expectation, specific colours (Green-Brown, Red-Blue-Black, Yellow) and patterns (Plain, Spots, Mottled-Patches) were not associated with the evolution of caregiving behaviours. Only among species with male-only care did we find a positive association with the presence of Bars-Bands. The lack of strong associations between dorsal morphology and caregiving activities suggest that these colours and patterns may serve other functions and that predation risk of parental care is mediated in other ways. As a strongly sexually selected trait, dichromatism is an effective solution to attract mates, but we find here that its evolution appears to preclude the evolution of parental care behaviour in anurans.