Helminths of Ross' and Greater White-fronted Geese Wintering in South Texas, U.S.A.

摘要

Helminth community structure and pattern were assessed in 16 Ross' geese, Chen rossii, and 46 greater white-fronted geese, Anser albifrons, collected during winter 1999-2000 in Kleberg County, Texas, U.S.A.. Helminths found in individual Ross' geese ranged from 1 to 6 species and from 1 to 95 individuals; infracommunities averaged 3.5 (+-) 0.3 (SE) species and 42.5 (+-) 7,7 individuals Ten species were found in the Ross' goose component community, in which Amidostomum anseris, Epomidiostomum crami, Heterakis dispar, and Trichostrongylus tenuis were the most prevalent and numerically dominant Helminths found in individual white-fronted geese ranged from 1 to 7 species and from 4 to 117 individuals; infracommunities averaged 4.2 (+-) 0.2 species and 28.9 (+-) 4.0 individuals. Sixteen species were found in the white-fronted goose component community. Epomidiostomum crami, Amidostomum spatulatum, and T. tenuis were the most prevalent and numerically dominant. In white-fronted geese, chi-square and analysis of variance comparisons were possible for A. anseris, A,, spatulatum, E. crami, T. tenuis, and Drepanidotaenia sp. Prevalence was significantly higher in the juvenile sample than the adult sample for A, anseris and T. tenuis, whereas A, spatulatum was significantly lower in the juvenile sample. Prevalence of T. tenuis was significantly higher in males than females. Mean abundance of A. spatulatum was significantly higher in the adult sample than the juvenile sample, whereas T. tenuis was significantly higher in the juvenile sample. No significant differences in mean abundance were observed because of host sex. On the basis of percentage similarity and Jaccard's indices, component communities between juvenile and adult white-fronted geese were most similar, followed by male and female white-fronted geese, and juvenile Ross' and white-fronted geese. Relatively low species richness, preponderance and numerical dominance of direct life cycle nematodes, and absence of helminths in a number of habitats suggests that the mainly herbivorous diet of Ross' and white-fronted geese dramatically influenced helminth community structure and pattern on the wintering grounds.