Padrões de associação e distribuição de helmintos em anuros no Brasil

Abstract

In the Atlantic Forest, there is a set of amphibian species that represents a good model of study to investigate the relationships of parasitism by helminths. Thus, in the present thesis, the fauna of helminths associated to the different host species of anurans in Brazil was evaluated. In the first chapter, a review was carried out on the patterns of association and distribution of helminths in anuran species in Brazil. A total of 109 species of Brazilian anurans were recorded containing at least one parasite helminth, with the families Bufonidae and Leptodactylidae being the most representative. Most anurans (56.7%) had less than ten species of helminths registered. Leptodactylus latrans was the species with the highest recorded helminth richness (N = 61 spp.). A total of 164 species of helminths were recorded, being Cosmocerca parva the helminth that occurred in most species of anurans (N = 20 spp.). Helminth parasitism can be influenced by the body size and the type of environment the host occupies. The influence of diet and sex still needs a better understanding, since the studies that addressed this issue for the anurans of Brazil are rare (if not absent). In the second chapter, the relationship between the helminth community and their leaf litter frog hosts in the Guapiaçu Ecological Reserve (REGUA), RJ, Brazil, was evaluated. In total, 561 leaf litter anurans belonging to 13 species and seven families were sampled in REGUA. In total, 1616 helminths were classified in 13 species belonging to the phyla Acanthocephala (2 spp., 2 families), Nematoda (10 spp., 6 families) and Platyhelminthes (Class Cestoda, 1 sp., 1 family). Among the 12 species of parasitized anurans, the richness of helminths ranged from one (in Dendrophryniscus brevipollicatus) to ten (in Rhinella ornata) species. The species of helminths that infected the greatest number of species of anuran hosts were Cosmocerca parva (N = 9) and Cosmocerca brasiliense (N = 8). In the third chapter, the effect of host species' body size and abundance on the richness, prevalence and mean intensity of infection (MII) were evaluated. There was a positive and significant relationship between the helminth richness and the maximum snout-vent length (SVL) of each anuran species. There was also a positive and significant relationship between the MII and the abundance and and maximum SVL of each species of anuran, however, only SVL significantly influenced IMI. The SVL of the anurans positively and significantly influenced the total intensity of parasite helminths in the four species evaluated. For most species, there were no sexual differences in total helminth intensity, however, females of H. binotatus had a higher total helminth intensity than males, even when the effect of SVL was excluded in the analysis