Variation in the helminth community structure of three sympatric sigmodontine rodents from the coastal Atlantic Forest of Rio de Janeiro, Brazil

Abstract

One hundred and eighty specimens of sigmodontine rodents living in sympatric conditions were collected in the Atlantic Forest in the state of Rio de Janeiro, Brazil (25 Akodon cursor, 98 Akodon montensis and 57 Oligoryzomys nigripes) to examine whether the helminth structure and component communities can be characterized among these three closely related rodents. The parasite species richness was 9 in A. cursor, 12 in A. montensis and 12 in O. nigripes. Five species were common to the three rodent species, and eight were common to A. cursor and A. montensis. The trichostrongylids - Stilestrongylus eta in A. cursor, S. aculeata in A. montensis and S. lanfrediae in O. nigripes - were the species with highest dominance frequency and determined the characterization of individual community structures. The prevalence and abundance of concurrent helminth species among rodents were significantly different. Canonical multivariate analysis demonstrated a similar helminth community structure between A. cursor and A. montensis but a high discrepancy between Akodon spp. and O. nigripes. Thus, the data indicated that small rodents such as A. cursor, A. montenis and O. nigripes that are sympatric and phylogenetically related have a different community structure, but similar component community, suggesting the role of helminth specificity and the hosts' habitats as determinants in structuring their helminth communities.

Helminth communities in three sympatric rodents from the Brazilian Atlantic Forest: contrasting biomass and numerical abundance

“…Interestingly, although the biomass pattern is different from numeric abundance, this difference does not influence the helminth distribution community, since the canonical multivariate analysis using biomass data was similar to that observed in Simões et al (2011) using numeric abundance in the three sympatric rodents.…”

“…This pattern may be determined by the three most abundant helminth species in O. nigripes which present a high biomass, although the same was not seen in Akodon spp.. Thus, sympatric hosts with different behaviour present different helminth community structure (Simões et al, 2011) and different parasite body size. Studies on ecology of the host-parasitehabitat are necessary considering the biomass pattern in parasite communities .…”

“…Usually parasite communities and infracommunities are described only numerically, specially in rodents (Fuentes et al, 2004;Maldonado Junior et al, 2006;Simões et al, 2009Simões et al, , 2011. Nevertheless, the size of the parasites is relevant information in order to understand how much parasite biomass can be sustained and how it can determine the helminth community structure.…”

“…Bio-security techniques and individual safety equipment were used during all procedures involving animals or biological samples (Lemos and D'Andrea, 2006). After being euthanised under biological safety procedures, the helminths were collected and identified as described by Simões et al (2011).…”

“…The three species living in sympatric conditions in the Atlantic Forest (Gentile and Fernandez, 1999), and share soil resources. Simões et al (2011) observed using numeric descriptors that sympatric rodents phylogenetically related have a different community structure although it presented a similar component community.…”