Trophic niche of two syntopic stream-dwelling tadpoles (Amphibia: Hylodidae) in an Atlantic Forest area, southeastern Brazil

ABSTRACT The feeding ecology of Neotropical tadpoles remains poorly understood, and, to our knowledge, no published studies have addressed the diet of tadpoles in Hylodidae. Here, we examine the feeding ecology of Crossodactylus gaudichaudii Duméril & Bibron, 1841 and Hylodes pipilans Canedo & Pombal, 2007 tadpoles co-occurring in stream habitats within the Brazilian Atlantic Forest. Tadpoles were collected from two streams where both species coexist, and periphyton samples were taken from the same sites to assess food availability. Gut content analysis revealed the presence of algae, cyanobacteria, detritus, fungi, insects, fern spores and pollen, protozoans, and rotifers in both species. The most frequently consumed items were detritus, fungi, protozoans, algae, and insects, with detritus being the dominant items in numerical terms. Trophic niche breadths were similar between the two species, and niche overlap was high. In terms of electivity, both species consumed rotifers and insects more frequently than expected based on environmental availability, whereas protozoans, fern spores and pollen, and algae were consumed less frequently than their availability would suggest. These findings indicate that C. gaudichaudii and H. pipilans tadpoles have generalist diets and appear to have similar filtering rates and abilities to ingest particles of varying sizes in their stream habitats.