Larval Diet in Bromeliad Pools: A Case Study of Tadpoles of Two Species in the Genus Scinax (Hylidae)

Many species of frogs that breed in bromeliads exhibit parental care as females deposit unfertilized eggs to feed the tadpoles. Treefrogs of the genus Scinax are not known to exhibit this behavior, even though they have exotrophic tadpoles. The purpose of this study was to describe qualitatively and quantitatively the diets of tadpoles of hylids S. littoreus and S. perpusillus developing in the phytothelm of Alcantarea glaziouana (Bromeliaceae). We evaluate if there are seasonal and spatial differences (between tadpoles living in the central tank and the lateral tanks) in the diet, and to test for food selectivity of the species. The most abundant items in the diet of tadpoles of both species were, respectively, algae, fungi, and protozoa. Detritus and plant debris were present in the diet of more than 90% of the tadpoles of the two species. The trophic niche breadth for S. littoreus was 1.26, whereas that for S. perpusillus was 1.54. The tadpole diets were seasonally conservative for both tadpole species and spatially similar only for S. perpusillus. Tadpoles of Scinax littoreus showed differences in diet, depending on the microhabitat in which they developed in the bromeliad, and showed electivity favorable for fungi but negative for copepods. Our data suggest that tadpoles of S. perpusillus are, in general, non-selective omnivores feeding on items in a similar proportion to their occurrence in the environment, while tadpoles of S. littoreus are more selective-feeders, avoiding animal items.