Limits to local adaptation in six populations of the annual plant Diodia teres

Authors

  • Joe Hereford,

    1. Department of Biological Science, Florida State University, Tallahassee, FL 32306-1100, USA;
    2. Present address: University of Maryland, Department of Biology, Biology Psychology Building, College Park MD 20742-4415, USA
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  • Alice A. Winn

    1. Department of Biological Science, Florida State University, Tallahassee, FL 32306-1100, USA;
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Author for correspondence:
Joe Hereford
Tel:+1 301 405 1640
Fax:+1 301 314 9358
Email: hereford@umd.edu

Summary

  • • Local adaptation is common, but tests for adaptive differentiation frequently compare populations from strongly divergent environments, making it unlikely that any influence of stochastic processes such as drift or mutation on local adaptation will be detected. Here, the hypothesis that local adaptation is more likely to develop when the native environments of populations are more distinct than when they are similar was tested.
  • • A reciprocal transplant experiment including two populations from each of three habitats was conducted to determine the pattern of local adaptation. In addition to testing for local adaptation at the population level, the hypothesis was tested that local adaptation is more common between populations from different habitats than between populations from the same habitat.
  • • Local adaptation was not common, but more evidence was found of local adaptation between populations from different habitats than between populations from the same habitat. Two instances of foreign genotype fitness advantage confirm that stochastic processes such as drift can limit local adaptation.
  • • These results are consistent with the hypothesis that stochastic processes can inhibit local adaptation but are more likely to be overwhelmed by natural selection when populations occur in divergent environments.

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