7 April 2003 The Effect of Metapopulation Processes on the Spatial Scale of Adaptation Across an Environmental Gradient (this article is formally unpublished due to loss of contact with the first author) Ian R. Wynne 1* , Robert J. Wilson 2, A.S. Burke 3, Fraser Simpson 1, Andrew S. Pullin 3, Chris D. Thomas 2 , James Mallet 1 1Galton laboratory, Department of Biology, University College London, 4 Stephenson Way, London NW1 2HE, UK.
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[email protected] . 2School of Biology, University of Leeds, Leeds LS2 9JT, UK.
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[email protected] . 3School of Biosciences, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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[email protected] . * Corresponding author and present address: Department of Population Ecology, Zoological Institute, Copenhagen University, Universitetsparken 15, DK-2100, København Ø; e-mail:
[email protected] . Tel: +45 3532 1280. Fax: +45 353 2150. Keywords : voltinism, adaptation, population genetic structure, connectivity, habitat networks Running header : The spatial scale of adaptation 1 ABSTRACT: We show that the butterfly Aricia agestis (Lycaenidae) is adapted to its thermal environment in via integer changes in the numbers of generations per year (voltinism): it has two generations per year in warm habitats and one generation per year in cool habitats in north Wales (UK). Voltinism is an “adaptive peak” since individuals having an intermediate number of generations per year would fail to survive the winter, and indeed no populations showed both voltinism types in nature. In spite of this general pattern, 11% of populations apparently possess the “wrong” voltinism for their local environment, and population densities were lower in thermally intermediate habitat patches.