Richness, origin and structure of anEimeriacommunity in a population of Eastern cottontail (Sylvilagus floridanus) introduced into Italy

Abstract

SUMMARYThe composition and structure of a community ofEimeriawas investigated in a population of Eastern cottontail (Sylvilagus floridanus) introduced into Italy. EightEimeriaspecies were found, of which all but 1 had North American origins and were presumably introduced into Italy together with imported cottontails. The success of cottontails in spreading microparasites is probably related to their massive release for hunting purposes. Nearly all cottontails were infected with at least 1Eimeriaspecies, with bimonthly prevalence ranging from 0–6·3% (E. leporis) to 42·9–89·3% (E. environ). Bayesian model averaging and multivariate techniques were used to investigate the relationships between the occurrence of each parasite and the structure of the relative community. Among the host parameters, only sex was found to be associated with the prevalence ofE. honessi, while the rest of the parameters were only weakly correlated with prevalence and species richness. This indicates that individual phenotypic host characteristics are probably less important than environmental factors in determining levels of parasite prevalence and diversity. The community ofEimeriaspecies was probably structured by competition, with less species co-occurrence than expected under a null hypothesis. This was made evident by the low co-occurrence ofE. environandE. neoirresiduawithE. poudrei,E. honessi, andE. maior.