Maintenance of a Hybrid Zone: The Role of Female Mate Choice
MetadataShow full item record
Hybrid zones between different plumage morphs are common in birds. These zones can be maintained by (1) divergent selection pressures on either side of the zone or (2) some restriction to mating between the forms that limits gene flow from one side to the other. In eastern Australia, there is a distinct hybrid zone between two plumage forms of the Australian Magpie (Cracticus tibicen), with black-backed birds in the north, white-backed birds in the south, and both forms plus intermediates in a zone ~100 km wide. On the basis of social groups, there is no evidence of assortative mating in the hybrid zone. However, extrapair fertilizations (EPF) occur in other Australian Magpie populations and, thus, may also occur in the hybrid zone. We examined evidence of EPFs in the hybrid zone to test for either (1) positive assortative mating or (2) preference for the brighter plumage form. Although there were significant levels of EPFs of ~30%, there was no evidence for positive assortative mating or preference for the brighter white-backed males. Other explanations for the current distribution of the hybrid zone and its maintenance will need to be investigated.
Published as citation above. Copyright 2011 by the Regents of the University of California & the American Ornithologists' Union. Copying and permissions notice: Authorization to copy this content beyond fair use (as specified in Sections 107 and 108 of the U. S. Copyright Law) for internal or personal use, or the internal or personal use of specific clients, is granted by the Regents of the University of Californiaon behalf of the American Ornithologists' Union for libraries and other users, provided that they are registered with and pay the specified fee via Rightslinkcopyright on [Caliber (http://caliber.ucpress.net/)/ AnthroSource (http://www.anthrosource.net)] or directly with the Copyright Clearance Center, http://www.copyright.com