Intestinal helminths of lesser scaup ducks: patterns of association

Abstract

The helminth communities of the small intestines of 45 lesser scaup ducks sampled from 13 lakes in Alberta, Canada, were examined for patterns of association among species. A core of eight frequent, numerous, and positively associated species provided a basic similarity across all host individuals. Six of these core species are specialists in lesser scaup, and the other two are generalists in waterfowl. A group of eight moderately frequent and numerous species, which were positively associated with the core species but not with each other, also contributed to this similarity; these secondary species included two specialists in scaup and three generalists in waterfowl. The 36 remaining "satellite species" appeared to be distributed randomly among birds. Variations among communities in individual birds were due largely to (i) differences in the numbers of two suites of helminth species, one using Hyalella azteca and the other Gammarus lacustris as intermediate host; (ii) differences in the numbers of the Hyalella suite, and in the presence or absence of some secondary or satellite species, associated with the lake from which the duck was taken; and (iii) differences in the total numbers of helminths per duck, which may be associated with differential susceptibility of individual ducks.

Ecological analyses of the intestinal helminth communities of the wolf, Canis lupus, in Spain

“…We found, as in Bush and Holmes (1986a), mostly significant co-occurrences between their own core species, and between core and secondary species.…”

“…1), which indicates that the community consists of three groups of species. The identification of these groups as "core", "secondary" and "satellite species" was based, as in Bush and Holmes (1986a), on the application of Caswell's and Hanski's dichotomy (Caswell 1978, Hanski 1982, 1991) using prevalence to represent regional dispersion and intensity to represent abundance. There was a positive correlation (Spearman rank correlation, r = 0.685, p < 0.01) between frequency and intensity.…”

Spatiotemporal distributions of intestinal helminths in female lesser scaupAythya affinisduring spring migration from the upper Midwest, USA

“…Capillaria species often occur at high prevalences but low intensities and rarely cause disease in wild hosts (Yabsley, 2008). Strongyloides species occurred in all regions and years of the study, and have been reported in scaup breeding in Alberta, Canada (Bush & Holmes, 1986b). Similar to capillarids, strongyloids rarely produce overt signs of pathology unless host health is compromised and unable to initiate an immune response (Viney & Lok, 2007).…”

“…Fresh tap-water was added to the beaker containing the sample until the total volume equalled 100 ml and a 10% subsample (10 ml) was removed using an aliquot technique (Bush & Holmes, 1986b). The aliquot was transferred to a gridded Petri dish and systematically examined under a stereoscope.…”

Ecology and Zoogeography of Parasites

“…A permanent component are also influents, which do not occur as abundantly as the dominants, and accessory species that appear only sporadically. The range of the frequency of occurrence of parasites is also described by specific terminology that is also used too describe free-living organisms (Bush & Holmes, 1986). Core species are those that occur frequently and abundantly.…”