Heightened exposure to parasites favors the evolution of immunity in brood parasitic cowbirds

Evolutionary Biology
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Abstract

Immunologists and evolutionary biologists are interested in how the immune system evolves to fit an ecological niche. We studied the relationship between exposure to parasites and strength of immunity by investigating the response of two species of New World cowbirds (genus Molothrus, Icteridae), obligate brood parasites with contrasting life history strategies, to experimental arboviral infection. The South American shiny cowbird (M. bonariensis) is an extreme host-generalist that lays its eggs in the nests of >225 different avian species. The Central American bronzed cowbird (M. aeneus) is a relative host-specialist that lays its eggs preferentially in the nests of approximately 12 orioles in a single sister genus. West Nile virus provided a strong challenge and delineated immune differences between these species. The extreme host-generalist shiny cowbird, like the North American host-generalist, the brown-headed cowbird, showed significantly lower viremia to three arboviruses than related icterid species that were not brood parasites. The bronzed cowbird showed intermediate viremia. These findings support the interpretation that repeated exposure to a high diversity of parasites favors the evolution of enhanced immunity in brood parasitic cowbirds and makes them useful models for future studies of innate immunity.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Heightened exposure to parasites favors the evolution of immunity in brood parasitic cowbirds
Series title Evolutionary Biology
Volume 38
Issue 2
Year Published 2011
Language English
Publisher Springer
Publisher location Netherlands
Contributing office(s) Patuxent Wildlife Research Center
Description 11 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Evolutionary Biology
First page 214
Last page 224
Country United States