Larval cannibalism in Phyllobates poison frogs

Cannibalistic behaviour between tadpoles of dendrobatoid poison frogs has been observed in several species with complex parental care dynamics, leading to the idea that it may have played a role in the evolution of parental care. However, the existence or characteristics of this behaviour beyond a handful of well-studied species remains largely unknown. I report direct and indirect observations of larval cannibalism in two species of the genus Phyllobates, which seem to occur less frequently than in other, better studied species, and possibly associated with body size differences. Beyond expanding the phylogenetic breadth of tadpole cannibalism among poison frogs, my observations point to interesting aspects of this behaviour, such as its apparently plastic and continuous nature, and highlight the importance of studying other lineages to understand the its drivers and effects on poison frog evolution.