HELMINTH COMMUNITY STRUCTURE OF THREE SIGMODONTINE RODENTS IN THE ATLANTIC FOREST, SOUTHERN BRAZIL

Abstract

Ecological studies of host-parasite interactions are common in rodents. However, despite the widespread occurrence of endoparasites in those animals, there is a lack of information about the community structure of these parasites. The aims of this study were to describe the species composition and the community structure of helminths of the rodents Oligoryzomys nigripes , Akodon montensis and Euryoryzomys russatus (Rodentia, Sigmodontinae), and to investigate the influence of host species, age and gender on the abundance and prevalence of helminths. The pattern of the metacommunity structure of the helminths of A. montensis was also analysed. Small mammals were captured in Serra do Tabuleiro State Park, Santo Amaro da Imperatriz, state of Santa Catarina, Brazil. Helminths were identified and counted. Each species had its abundance, intensity and prevalence estimated for each host. The influence of host species, age and gender on abundance and prevalence of helminths was tested using generalized linear models (GLM). The metacommunity was analysed by calculating the Elements of Metacommunity Structure (EEM) for infracommunities. In O. nigripes, the species Guerrerostrongylus zetta and Stilestrongylus lanfrediae (Nematoda, Heligmonellidae) were found. A. montensis harboured G. zetta , Trichofreitasia lenti (Nematoda, Heligmonellidae), Trichuris navonae (Nematoda, Trichuridae), Angiostrongylus sp. (Nematoda, Angiostrongylidae), Litomosoides chagasfilhoi (Nematoda, Onchocercidae) and Rodentolepis akodontis (Plathyhelmintes, Cestoda). In the E. russatus rodent, the species G. zetta, Stilestrongylus rolandoi (Nematoda, Heligmonellidae) and Raillietina guaricanae (Plathyhelmintes, Cestoda) were found. This study presented new records of the helminths S. rolandoi and R. guaricanae in E. russatus , and of L. chagasfilhoi in A. montensis . The helminth metacommunity structure of A. montensis presented a random pattern of species distribution, characterized by a non-coherent structure along the environmental gradient, indicating different environmental requirements due to the infection of this host by helminths with different life cycles.