Trematode parasites associated with amphibians from a rice field in the northeastern Argentina

Abstract

In altered environments, such as agricultural lands, studies of amphibian parasites can provide helpful information about the food web structure, parasite species abundance and composition, and environmental stress. Here, we investigate the parasitic digeneans in three amphibian families (Leptodactylidae, Bufonidae and Hylidae) in a rice field (30 ha) from Corrientes Province, Argentina. A total of 171 amphibian specimens were collected between March 2017 and February 2018. Amphibian trematode parasites in this area included 18 species, with dominance of common species. The trematode fauna was characterized by only one species (Choledocystus vitellinophillum) with high prevalence (>50%). The dominant adult species corresponded to Catadiscus propinquus for most of the hosts (80%), and when only larval trematodes were analysed, the dominant metacercariae in most hosts (60%) were strigeids larvae. Of the total trematode individuals (n = 278), 57% corresponded to metacercariae that complete their life cycles mainly in birds. The amphibians Leptodactylus chaquensis and Lysapsus limellus presented high species richness. This is related to the microhabitats occupied by these hosts as well as with the biology of their parasites. Infection of all the trematode taxa for which larvae and adults were examined occurs through a sequence of trophic relationships. Finally, the results expand the knowledge of the biodiversity and ecology of parasite helminths in amphibians from agricultural landscapes; furthermore, this information is a fundamental baseline to quantify the loss of biodiversity and assess the health of the ecosystem.