Large-scale patterns of host use by parasites of freshwater fishes

Authors
Citation
R. Poulin, Large-scale patterns of host use by parasites of freshwater fishes, ECOL LETT, 1(2), 1998, pp. 118-128
Citations number
40
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology
Journal title
ECOLOGY LETTERS
ISSN journal
1461-023X → ACNP
Volume
1
Issue
2
Year of publication
1998
Pages
118 - 128
Database
ISI
SICI code
1461-023X(199809)1:2<118:LPOHUB>2.0.ZU;2-Z
Abstract
Organisms that are abundant locally in a habitat patch are commonly observe d to be frequent regionally, or among patches. In parasites, species presen t in high numbers in host individuals are also present in many individuals in the host population. On a larger scale, however, when host species are c onsidered as patches, we may expect the opposite pattern because of the cos t of producing mechanisms to evade the immune responses of several host spe cies. Thus parasite species exploiting many host species may achieve lower average abundance in their hosts than parasite species exploiting fewer hos t species. This prediction was tested with data from 188 species of metazoa n parasites of freshwater fish, using a comparative approach that controlle d for study effort and phylogenetic influences. A negative correlation was found between the number of host species used by parasites and their averag e abundance in hosts, measured as either prevalence or intensity of infecti on. There was no evidence that parasite species fall into distinct categori es based on abundance patterns, but rather that they fall along a continuum ranging from a generally low abundance in many host species, to a generall y high abundance in few host species. These results applied to both ecto- a nd endoparasites. The pattern observed suggests the existence of a trade-of f between how many host species a parasite can exploit and how well it does on average in those hosts.