Genital divergence in sympatric sister snails

Authors

  • J. Hollander,

    Corresponding author
    1. Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
    • Department of Biology, Aquatic Ecology, Lund University, Lund, Sweden
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  • C. M. Smadja,

    1. Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
    2. Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de l'Evolution UMR 5554, Montpellier, France
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  • R. K. Butlin,

    1. Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
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    • These authors contributed equally.
  • D. G. Reid

    1. Department of Life Sciences, Natural History Museum, London, UK
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    • These authors contributed equally.

Correspondence: J. Hollander, Department of Biology, Aquatic Ecology, Lund University, SE-223 62 Lund, Sweden.

Tel.: +46 46 222 34 73; fax: +46 46 222 45 36; e-mail: johan.hollander@biol.lu.se

Abstract

A pattern of greater divergence in mating traits between sister-species pairs with overlapping ranges than between allopatric species pairs is expected if reinforcement commonly contributes to speciation. Few large-scale comparative analyses have addressed this prediction, especially for genital form. Here, we show that penial morphology follows the predicted pattern in 40 robustly identified sister-species pairs in the marine gastropod subfamily Littorininae. Further work is needed to exclude other processes that may contribute to genital divergence between sympatric species, but the clear pattern we observe strongly suggests a role for genital form in reproductive isolation in this large clade.

Ancillary