Trophic interactions of two aquatic anurans from the mid-elevation evergreen forests of the Western Ghats, India

Food is an important resource that is often partitioned among co-occurring species. Anurans (Frogs and Toads) are a diverse group of vertebrates distributed globally and are known to be generalist predators. While the dietary ecology of anurans has been extensively studied in the Neotropics, our knowledge from parts of South and SE Asia is limited. Here, we study the dietary ecology of two anurans, belonging to ancient families (Micrixalidae and Nyctibatrachidae) from a riverine ecosystem of the wet-evergreen forests of the Western Ghats, India. We quantified both the quantity and composition of diet by flushing the stomachs of anurans. The quantity of prey items consumed by the two species as well as sexes was scaled with body size. The composition, as well as dietary niche, were significantly different between the two species. Despite the diet composition being different, their diets overlapped partially but the overlap was significantly greater than expected. Finally, we found the diet composition of the two species to be correlated with morphological characteristics of the head shape and activity period. Overall, our findings suggest that the two species partition resources along temporal, microhabitat, and morphological axes and appear to be generalist, sit-and-wait foragers. Our findings underscore the need for future research on dietary ecology in the fast-changing landscapes of the Western Ghats as well as other parts of Asia.