Home is where the high-quality resources are: nursery characteristics and territory distribution suggest reproductive resource defense in golden rocket frogs

Abstract

For externally fertilizing animals, the early stages of development are often the most precarious. In the face of multiple abiotic and biotic stressors, parents must assess and select rearing sites that maximize the probability of offspring survival. This is particularly true for Neotropical poison frogs, many of which transport tadpoles to small pools of water called phytotelmata that serve as larval rearing sites. In these systems, pool choice can have a large effect on offspring growth and survival. Here, we studied the golden rocket frog (Anomaloglossus beebei, Aromobatidae), a territorial phytotelm-breeding frog that lives exclusively in giant tank bromeliads (Brocchinia micrantha), to examine phytotelm selection and reproductive resource defense. We first quantified the characteristics of phytotelmata and found that tadpoles were more likely to occur in pools with low levels of mucilage and in leaves at intermediate heights on the plant. We additionally found that low mucilage pools have significantly clearer water, have higher concentrations of dissolved oxygen, and are exposed to lower levels of photosynthetically active radiation. We then mapped the spatial distribution of pools with low levels of mucilage in relation to male territories and found that these “clear” pools are (1) more likely to be within male territories than outside of them, and (2) territory centroids are closer to clear pools than are random locations. Overall, our results show that male golden rocket frogs defend territories that include preferred tadpole deposition sites, suggesting a direct relationship between high-quality reproductive resources and territory defense.