Faithful fathers and crooked cannibals: the adaptive significance of parental care in the bush frog Raorchestes chalazodes, Western Ghats, India

Parental care has evolved many times in multiple taxa and, by definition, enhances offspring survivorship. Anurans exhibit a diverse array of parental care behaviors, but studies examining their adaptive significance in an evolutionary context are limited. The critically endangered bush frog, Raorchestes chalazodes (Rhacophoridae), only breeds inside hollow internodes of the endemic bamboo (Ochlandra travancorica) in the southern Western Ghats of India from June through October. From systematic surveys, we established that adult males are sole caregivers exhibiting egg attendance and egg guarding behavior. Predation was the main cause of egg mortality in the absence of an attending male; the majority of predation events were caused by conspecific males. The results highlight the role of regional and microhabitat-specific selection pressures such as strong seasonally, limited resources, and competition for oviposition sites. Oviposition sites are in high demand, but in short supply and by consuming unattended eggs, the conspecific male may benefit from nutritional gains as well as mating opportunities at the oviposition site. Our work lays foundations for further examination of social and reproductive behaviors of anurans not only in the Western Ghats but also in South and Southeast Asia.