4000 years of phenotypic change in an island bird: heterogeneity of selection over three microevolutionary timescales.

Clegg, S.M., Frentiu, F.D., Kikkawa, J., Tavecchia, G., & Owens, I.P. (2008) 4000 years of phenotypic change in an island bird: heterogeneity of selection over three microevolutionary timescales. Evolution, 62(9), pp. 2393-2410.

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Pronounced phenotypic shifts in island populations are typically attributed to natural selection, but reconstructing heterogeneity in long-term selective regimes remains a challenge. We examined a scenario of divergence proposed for species colonizing a new environment, involving directional selection with a rapid shift to a new optimum and subsequent stabilization. We provide some of the first empirical evidence for this model of evolution using morphological data from three timescales in an island bird, Zosterops lateralis chlorocephalus. In less than four millennia since separation from its mainland counterpart, a substantial increase in body size has occurred and was probably achieved in fewer than 500 generations after colonization. Over four recent decades, morphological traits have fluctuated in size but showed no significant directional trends, suggesting maintenance of a relatively stable phenotype. Finally, estimates of contemporary selection gradients indicated generally weak directional selection. These results provide a rare description of heterogeneity in long-term natural regimes, and caution that observations of current selection may be of limited value in inferring mechanisms of past adaptation due to a lack of constancy even over short time-frames.

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36 citations in Scopus
34 citations in Web of Science®
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ID Code: 54093
Item Type: Journal Article
Refereed: Yes
Keywords: adaptation, microevolution, silvereyes, island biology
DOI: 10.1111/j.1558-5646.2008.00437.x
ISSN: 0014-3820
Subjects: Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000)
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Deposited On: 12 Oct 2012 01:08
Last Modified: 16 Jul 2017 21:01

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