Specialized breeding in plants affects diversification trajectories in Neotropical frogs

Many animals breed exclusively in plants that accumulate rainwater (phytotelma; e.g., bromeliad, bamboo, fruit husk, and tree hole), to which they are either physiologically or behaviorally specialized for this microhabitat. Of the numerous life-history modes observed in frogs, few are as striking or potentially consequential as the transition from pond- or stream-breeding to the deposition of eggs or larvae in phytotelmata. Such specialization can increase offspring survivorship due to reduced competition and predation, representing potential ecological opportunity for adaptive radiation, yet few lineages of phytotelma-breeding frogs appear to have diversified extensively after such a transition, at least in the New World. We use a phylogeny of Neotropical frogs and data on breeding microhabitat to understand the evolutionary transitions involved with specialized phytotelma-breeding. First, we find that phytotelma-breeding is present in at least 168 species in 10 families of frogs. Across the phylogeny, we estimate 14 origins of phytotelma-breeding and 115 reversals, showing that phytotelma-breeding is a highly labile character. Second, phytotelma-breeding lineages overall have higher net diversification than nonphytotelma-breeding ones. This specialization represents an ecological opportunity resulting in increased diversification in most families with phytotelma-breeding lineages, whereas phytotelma-breeding toads have restricted diversification histories.