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Temperature‐dependent costs of parasitism and maintenance of polymorphism under genotype‐by‐environment interactions
Author(s) -
VALE P. F.,
STJERNMAN M.,
LITTLE T. J.
Publication year - 2008
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2008.01555.x
Subject(s) - biology , parasite hosting , parasitism , coevolution , genetic variation , trait , genotype , daphnia , daphnia magna , virulence , host (biology) , epistasis , genetic variability , ecology , zoology , genetics , crustacean , gene , chemistry , organic chemistry , toxicity , world wide web , computer science , programming language
The maintenance of genetic variation for infection‐related traits is often attributed to coevolution between hosts and parasites, but it can also be maintained by environmental variation if the relative fitness of different genotypes changes with environmental variation. To gain insight into how infection‐related traits are sensitive to environmental variation, we exposed a single host genotype of the freshwater crustacean Daphnia magna to four parasite isolates (which we assume to represent different genotypes) of its naturally co‐occurring parasite Pasteuria ramosa at 15, 20 and 25 °C. We found that the cost to the host of becoming infected varied with temperature, but the magnitude of this cost did not depend on the parasite isolate. Temperature influenced parasite fitness traits; we found parasite genotype‐by‐environment (G × E) interactions for parasite transmission stage production, suggesting the potential for temperature variation to maintain genetic variation in this trait. Finally, we tested for temperature‐dependent relationships between host and parasite fitness traits that form a key component of models of virulence evolution, and we found them to be stable across temperatures.