POSITIVE FEEDBACK BETWEEN ECOLOGICAL AND REPRODUCTIVE CHARACTER DISPLACEMENT IN A YOUNG AVIAN HYBRID ZONE
Article first published online: 14 DEC 2011
© 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.
Volume 66, Issue 4, pages 1167–1179, April 2012
How to Cite
Vallin, N., Rice, A. M., Bailey, R. I., Husby, A. and Qvarnström, A. (2012), POSITIVE FEEDBACK BETWEEN ECOLOGICAL AND REPRODUCTIVE CHARACTER DISPLACEMENT IN A YOUNG AVIAN HYBRID ZONE. Evolution, 66: 1167–1179. doi: 10.1111/j.1558-5646.2011.01518.x
- Issue published online: 6 APR 2012
- Article first published online: 14 DEC 2011
- Accepted manuscript online: 22 NOV 2011 12:42AM EST
- Received November 30, 2010, Accepted October 30, 2011, Data Archived: Dryad doi:10.5061/dryad.td271t1d
- Collared flycatcher;
- ecological character displacement;
- pied flycatcher;
- reproductive character displacement;
- sexual isolation;
Character displacement can reduce costly interspecific interactions between young species. We investigated the mechanisms behind divergence in three key traits—breeding habitat choice, timing of breeding, and plumage coloration—in Ficedula flycatchers. We found that male pied flycatchers became expelled from the preferred deciduous habitat into mixed forest as the superior competitor, collared flycatchers, increased in numbers. The peak in food abundance differs between habitats, and the spatial segregation was paralleled by an increased divergence in timing of breeding between the two species. Male pied flycatchers vary from brown to black with brown coloration being more frequent in sympatry with collared flycatchers, a pattern often proposed to result from selection against hybridization, that is, reinforcement. In contrast to this view, we show that brown male pied flycatchers more often hybridize than black males. Male pied flycatcher plumage coloration influenced the territory obtained in areas of co-occurrence with collared flycatchers, and brown male pied flycatchers experienced higher relative fitness than black males when faced with heterospecific competition. We suggest that allopatric divergence in resource defense ability causes a feedback loop at secondary contact where male pied flycatchers with the most divergent strategy compared to collared flycatchers are favored by selection.