Nonrandom dispersal drives phenotypic divergence within a bird population
Article first published online: 6 NOV 2013
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Ecology and Evolution
Volume 3, Issue 14, pages 4841–4848, November 2013
How to Cite
Ecology and Evolution 2013; 3(14): 4841–4848
- Issue published online: 25 NOV 2013
- Article first published online: 6 NOV 2013
- Manuscript Accepted: 14 MAR 2013
- Manuscript Revised: 13 MAR 2013
- Manuscript Received: 15 JAN 2013
- Andalusian Agency of Economy, Innovation and Science
- Spanish Ministry of Education and Science. Grant Number: I3PBDP2005
- Spanish CCYT. Grant Numbers: CGL2009-10652, CGL2011-29694, CGL2012-35232
- Ficedula hypoleuca ;
- habitat preferences;
- phenotypic divergence;
- pied flycatcher;
- population structure
Gene flow through dispersal has traditionally been thought to function as a force opposing evolutionary differentiation. However, directional gene flow may actually reinforce divergence of populations in close proximity. This study documents the phenotypic differentiation over more than two decades in body size (tarsus length) at a very short spatial scale (1.1 km) within a population of pied flycatchers Ficedula hypoleuca inhabiting deciduous and coniferous habitats. Unlike females, males breeding in the deciduous forest were consistently larger than those from the managed coniferous forest. This assortment by size is likely explained by preset habitat preferences leading to dominance of the largest males and exclusion of the smallest ones toward the nonpreferred coniferous forest coupled with directional dispersal. Movements of males between forests were nonrandom with respect to body size and flow rate, which might function to maintain the phenotypic variation in this heritable trait at such a small spatial scale. However, a deeply rooted preference for the deciduous habitat might not be in line with its quality due to the increased levels of breeding density of hole-nesting competitors therein. These results illustrate how eco-evolutionary scenarios can develop under directional gene flow over surprisingly small spatial scales. Our findings come on top of recent studies concerning new ways in which dispersal and gene flow can influence microevolution.