Interactions between endoparasites and anurans in the Nhecolândia Pantanal, Brazil.

We analyzed the distribution of endoparasites in five species of Hylidae frogs during their reproductive period, aiming to understand how the host's habitat influences the parasites. Five anuran species (Boana raniceps, Pithecopus azureus, Pseudis platensis, Scinax acuminatus and Scinax nasicus) were sampled in temporary and permanent ponds in Nhecolândia Pantanal, Brazil. A total of 276 individuals were collected, 43.84% of which were parasitized by endoparasites. Metacercariae of Diplostomidae gen. sp. were predominant, accounting for 85.94% of the total parasites found. Nematodes and cestodes were also identified, with nematodes representing 7.85% of the total parasites. Statistical analyses indicated that host body size was not a significant predictor of parasitism probability, although a weak negative correlation between host body size and parasite abundance was observed. Network analysis revealed a modular structure in the parasite-host interactions, with moderate connectivity. These results suggest that environmental factors, particularly those related to the aquatic habitats of anurans, play a fundamental role in shaping parasite community structure. This study provides important insights into the complex ecological interactions between anurans and their parasites, significantly contributing to the understanding of parasite-host interaction dynamics in the Pantanal ecosystem.