Breeding-site selection by the poison frog Ranitomeya biolat in Amazonian bamboo forests: an experimental approach

Habitat selection in amphibians has typically been investigated using species that breed in medium-sized to large bodies of water. So far, few studies have focused on tropical, phytotelm-breeding species. We examined habitat selection in the context of reproductive resource use by Ranitomeya biolat (Morales, 1992), a poison frog that uses bamboo internodes as breeding sites. We conducted field observations and experiments using bamboo and PVC sections to test the effect of physical and biotic factors on tadpole deposition. Our field observations indicated that water volume, as well as internode length, height, and angle, may be important for tadpole deposition. We predicted that adult R. biolat would deposit tadpoles in pools that are close to the ground, pools with high water volume, pools contained in long structures, and pools without conspecific tadpoles or heterospecific predators. Our experiments demonstrated that water volume and the length of the structure containing the pool affect the pattern of tadpole deposition. Tadpoles were also deposited more frequently in experimental pools containing no other tadpoles or no predators. Our results support the prediction that phytotelm-breeding species, to maximize their reproductive success, should deposit their tadpoles in pools with water volumes that maximize nutrient content and that present no competitors or predators.