Structure of enteric helminth communities in two populations of Eptesicus fuscus (Chiroptera)

Abstract

Twenty-one species of helminths were recovered from Eptesicus fuscus in Eau Claire, Wisconsin, and thirteen species were collected from E. fuscus in St. Peter, Minnesota. Contingency table analyses of all species pairs from each locality detected no interactions in the St. Peter group. In the Eau Claire group the trematode pairs Paralecithodendrium naviculum – Acanthatrium oligacanthum and Allassogonoporus marginalis – Ochoterenatrema diminutum exhibited positive associations, whereas P. naviculum was negatively associated with the cestode Hymenolepis roudabushi. When the intestinal distribution of each species was summed over all hosts from each locality, the intestinal overlap of each species pair averaged 31% in bats from Eau Claire and 24% in bats from St. Peter. The overlaps dropped to 2% in bats from Eau Claire and 1% in those from St. Peter when intestinal distributions were not summed across hosts. A randomization analysis of intestinal distributions for all pairs of species from the two localities revealed that H. roudabushi overlapped less than expected with P. naviculum in Eau Claire and with the trematode Plagiorchis vespertilionis in St. Peter. The intestinal distributions of four pairs of species from St. Peter and eight pairs from Eau Claire overlapped more than expected. We conclude that contemporary interactions are of minor importance in structuring infracommunities for the two localities and that positive interactions are more common than negative interactions.