RAPID EVOLUTION OF A SEXUALLY SELECTED TRAIT FOLLOWING POPULATION ESTABLISHMENT IN A NOVEL HABITAT
Article first published online: 9 MAY 2007
Volume 58, Issue 1, pages 166–174, January 2004
How to Cite
Yeh, P. J. (2004), RAPID EVOLUTION OF A SEXUALLY SELECTED TRAIT FOLLOWING POPULATION ESTABLISHMENT IN A NOVEL HABITAT. Evolution, 58: 166–174. doi: 10.1111/j.0014-3820.2004.tb01583.x
- Issue published online: 9 MAY 2007
- Article first published online: 9 MAY 2007
- Received March 21, 2003. Accepted August 12, 2003.
- Cited By
- Common garden experiment;
- dark-eyed junco;
- evolutionary rates;
- genetic drift;
- Junco hyemalis;
- phe-notypic plasticity;
Abstract Colonization of novel environments creates new selection pressures. Sexually selected traits are affected by the physical and social environment and should be especially susceptible to change, but this has rarely been studied. In southern California, dark-eyed juncos, (Junco hyemalis) naturally breed in mixed-coniferous temperate forests, typically from 1500 m to 3000 m in elevation. In the early 1980s, a small population became established in a coastal habitat, the University of California, San Diego campus, which has a mild, Mediterranean climate. I show that a sexually and socially selected signaling trait–the amount of white in the tail–has declined by approximately 22% as compared to mountain juncos. I address three main factors that could explain the difference between mountain and coastal juncos: phenotypic plasticity, genetic drift, and selection. Results indicate that the first two can be ruled out as the sole cause of the plumage change, which implies that selection contributed to the genetic differentiation from the mountain population. The estimated rate of evolution is about 0.2 haldanes, comparable with rates of change in systems where individuals have been artificially introduced into new environments (e.g., guppies and Drosophila). This is the first study to demonstrate evolution of a sexually selected trait after only several generations resulting from a natural invasion into a novel environment.