Comparison of the Helminth Faunas of Two Sympatric Top Carnivores from the Rolling Plains of Texas

Abstract

Analysis of data collected from previous studies on the helminth parasites of the bobcat, Felis rufus, and the coyote, Canis latrans, from the Rolling Plains of Texas indicated that of the 28 different helminth species recovered, six were common to both carnivore hosts. Bobcats and coyotes harbored 16 and 18 helminth species, respectively. Simpson's indices for both hosts were very low (0.10 and 0.12 for coyotes and bobcats, respectively) indicating a lack of dominance by particular helminth species. An index of similarity and an overlap index (Jaccard's coefficients) were low (29.5 and 21.4, respectively) indicating that the faunas of these two hosts were basically dissimilar with little sharing of helminth species. Im- portance indices of helminth faunas from both hosts revealed: 1) the bobcat with nine and coyote with seven dominant helminth species; 2) three and five codominant helminth species in the bobcat and coyote, respectively; 3) one and two successful immigrant species in the bobcat and coyote, respectively; and 4) the bobcat and coyote with three and four unsuccessful immigrant helminth species, respectively. Two common dominant species, Toxascaris leonina and Mesocestoides corti, were shared by both hosts. These hosts also shared two codominant species, Onicola canis and Alaria marcianae. Pterygondermatites ca- hirensis was a dominant species in the coyote, but an unsuccessful immigrant in the bobcat. Likewise, Spirocerca lupi was a codominant species in the coyote, but an unsuccessful immigrant in the bobcat. Chi-square analysis of the two dominant and two codominant helminth species shared between these hosts revealed a significantly greater frequency of occurrence of M. corti and 0. canis in the coyote. Comparison of mean infrapopulation densities of shared helminth species indicated that the coyote had a significantly greater mean worm burden of T. leonina and 0. canis than the bobcat. Thus, of the six shared helminths, two dominant species, T. leonina and M. corti, and two codominant species, 0. canis and A. marcianae, appeared to be successfully maintained by both carnivores, whereas the remaining two species, S. lupi and P. cahirensis, were parasites of coyotes and unsuccessful immigrants in the helminth fauna of bobcats.