Host–Parasite Interaction Networks of Helminths of Sigmodontine Rodents in Two Different Areas of the Brazilian Atlantic Forest

ABSTRACT Studies in parasite community ecology seek to understand species distributions along environmental gradients, as well as the processes associated with host–parasite interactions. Host–parasite interaction networks can identify potential routes of parasite transmission among hosts and determine which species play a central role in a community. Two host–parasite interaction networks from different regions were analyzed, considering three helminth parasite parameters (presence and absence, abundance, and prevalence) in rodent species. Network modularity, nestedness, and degree of specialization were calculated for each network to determine whether variations in the presence or abundance of rodent species and their helminth parasites led to differences in host–parasite interactions and network structure. Metrics of network centrality, degree, and betweenness were calculated for each rodent and helminth species in the two networks. The influence of the functional attributes of hosts and parasites, as well as their abundances, on network metrics was also evaluated. Higher network modularity than nestedness, along with high network specialization, was observed in both networks, suggesting functional and/or taxonomic specialization between helminth species and their hosts. Abundance was a more important predictor of the topological role of host and parasite species than their functional attributes. These findings suggest that, despite local differences, the structure of host–parasite interaction networks may be conserved across different environments, modulated by similar factors such as host–parasite coevolution, with the most abundant host and parasite species playing a central role in ecological networks.