Letter | Published:

Reinforcement drives rapid allopatric speciation

Nature volume 437, pages 13531356 (27 October 2005) | Download Citation



Allopatric speciation results from geographic isolation between populations. In the absence of gene flow, reproductive isolation arises gradually and incidentally as a result of mutation, genetic drift and the indirect effects of natural selection driving local adaptation1,2,3. In contrast, speciation by reinforcement is driven directly by natural selection against maladaptive hybridization1,4. This gives individuals that choose the traits of their own lineage greater fitness, potentially leading to rapid speciation between the lineages1,4. Reinforcing natural selection on a population of one of the lineages in a mosaic contact zone could also result in divergence of the population from the allopatric range of its own lineage outside the zone4,5,6. Here we test this with molecular data, experimental crosses, field measurements and mate choice experiments in a mosaic contact zone between two lineages of a rainforest frog. We show that reinforcing natural selection has resulted in significant premating isolation of a population in the contact zone not only from the other lineage but also, incidentally, from the closely related main range of its own lineage. Thus we show the potential for reinforcement to drive rapid allopatric speciation.

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We thank B. Phillips, J. MacKenzie, M. Tonione, J. Gardiner, M. Blows, J. Austin, M. Cunningham, H. McCallum, G. Dolman, S. Williams, H. Rundle, S. Chenoweth, A. Freeman, F. J. Rohlf and D. Wake. We are also grateful to B. Phillips and M. Cunningham for locating the contact zone. Supported by the National Science Foundation (C.M.), an Australian Postgraduate Award (C.J.H.), a University of Queensland Graduate School Research Travel Award (C.J.H.), the Cooperative Research Centre for Tropical Rainforest Ecology and Management (C.J.H.) and Queensland Parks and Wildlife Service.

Author information


  1. School of Integrative Biology, University of Queensland, St Lucia, Queensland 4072, Australia

    • Conrad J. Hoskin
    •  & Megan Higgie
  2. Queensland Parks and Wildlife Service, PO Box 975, Atherton, Queensland 4883, Australia

    • Keith R. McDonald
  3. Museum of Vertebrate Zoology, University of California, Berkeley, California 94720, USA

    • Craig Moritz


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Competing interests

Sequences are deposited in the EMBL database under the following accession numbers: AF304205–AF304229 (ref. 11) and AJ872186–AJ872201. Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Corresponding author

Correspondence to Conrad J. Hoskin.

Supplementary information

Word documents

  1. 1.

    Supplementary Methods and Results

    Details of the methods and analyses, and additional analyses and results not presented in the paper. The file is broken into sub-headings matching those in the ‘Methods’ section of the main paper. Included are 9 Supplementary Tables that present the results of ANCOVAs and contrasts referred to in the Supplementary Information.

  2. 2.

    Supplementary Figure 3

    Graph showing variation in male size in the southern lineage. The graph compares southern lineage males at Contact B (iS), at Contact A, and outside the contact region.

  3. 3.

    Supplementary Figure 4

    Graph showing call variation in the southern lineage. The graph compares southern lineage males at Contact B (iS), at Contact A, and outside the contact region.

  4. 4.

    Supplementary Figure 5

    Graph showing the relationship between call divergence and body size for N, S and iS.

PDF files

  1. 1.

    Supplementary Figure 1

    Map showing the sampling sites outside the contact region, and the lineage (N or S) of individuals at each site.

  2. 2.

    Supplementary Figure 2

    Map showing the sampling sites across the mosaic contact zone, and the lineage (N, S/iS or mixed) of individuals at each site.

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