Premium
HOST‐PARASITE COEVOLUTION: EVIDENCE FOR RARE ADVANTAGE AND TIME‐LAGGED SELECTION IN A NATURAL POPULATION
Author(s) -
Dybdahl Mark F.,
Lively Curtis M.
Publication year - 1998
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1998.tb01833.x
Subject(s) - biology , coevolution , host (biology) , parasite hosting , population , frequency dependent selection , evolutionary biology , natural selection , snail , clone (java method) , zoology , experimental evolution , selection (genetic algorithm) , genetics , ecology , gene , demography , artificial intelligence , sociology , world wide web , computer science
In theory, parasites can create time‐lagged, frequency‐dependent selection in their hosts, resulting in oscillatory gene‐frequency dynamics in both the host and the parasite (the Red Queen hypothesis). However, oscillatory dynamics have not been observed in natural populations. In the present study, we evaluated the dynamics of asexual clones of a New Zealand snail, Potamopyrgus antipodarum , and its trematode parasites over a five‐year period. During the summer of each year, we determined host‐clone frequencies in random samples of the snail to track genetic changes in the snail population. Similarly, we monitored changes in the parasite population, focusing on the dominant parasite, Microphallus sp., by calculating the frequency of clones in samples of infected individuals from the same collections. We then compared these results to the results of a computer model that was designed to examine clone frequency dynamics for various levels of parasite virulence. Consistent with these simulations and with ideas regarding dynamic coevolution, parasites responded to common clones in a time‐lagged fashion. Finally, in a laboratory experiment, we found that clones that had been rare during the previous five years were significantly less infectible by Microphallus when compared to the common clones. Taken together, these results confirm that rare host genotypes are more likely to escape infection by parasites; they also show that host‐parasite interactions produce, in a natural population, some of the dynamics anticipated by the Red Queen hypothesis.