Evol Ecol Res 2: 897-909 (2000)     Full PDF if your library subscribes.

Speciation by sexual selection in hybridizing populations without viability selection

Masakado Kawata¹ and Jin Yoshimura^2,3,4

¹Department of Ecology and Evolutionary Biology, Institute of Biology, Tohoku University, Aoba, Sendai 980-8578, Japan, ²Department of System Engineering, Shizuoka University, Hamamatsu 432-8561, Japan, ³NERC Centre for Population Biology, Imperial College at Silwood Park, Ascot, Berkshire SL5 7PY, UK and ⁴Department of Environmental and Forest Biology, State University of New York, College of Environmental Science and Forestry, Syracuse, NY 13210, USA

Author to whom all correspondence should be addressed.
e-mail: kawata@mail.cc.tohoku.ac.jp

ABSTRACT

We propose a new speciation mechanism for hybridizing populations based on frequency-dependent sexual selection theory. In contrast to previous reinforcement and symmetric speciation models, this model does not require viability selection for male sexual traits, selection against unfit hybrids or disruptive selection for ecological traits. The model assumes that females exhibit mating preferences based on male secondary sexual characters. Both female mating preferences and male secondary sexual traits are independent quantitative genetic traits. Females choose using one of five tactics. All individuals, including the hybrids, have the same ability to survive and reproduce. Two populations that differ only in their average values of female preference and male sexual traits are assumed to come into contact and hybridize. Most cases of the model frequently result in complete prezygotic isolation. The likelihood of speciation decreases with the degree of phenotypic overlap between the two merging populations. However, the probability of speciation is not zero even when the two merging populations are identical.

Keywords: reinforcement, sexual selection, speciation.

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        © 2000 Masakado Kawata. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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