uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Testing Mechanisms of Bergmann's Rule: Phenotypic Decline but No Genetic Change in Body Size in Three Passerine Bird Populations
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
2011 (English)In: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 178, no 2, 202-213 p.Article in journal (Refereed) Published
Abstract [en]

Bergmann's rule predicts a decrease in body size with increasing temperature and has much empirical support. Surprisingly, we know very little about whether "Bergmann size clines" are due to a genetic response or are a consequence of phenotypic plasticity. Here, we use data on body size (mass and tarsus length) from three long-term (1979-2008) study populations of great tits (Parus major) that experienced a temperature increase to examine mechanisms behind Bergmann's rule. We show that adult body mass decreased over the study period in all populations and that tarsus length increased in one population. Both body mass and tarsus length were heritable and under weak positive directional selection, predicting an increase, rather than a decrease, in body mass. There was no support for microevolutionary change, and thus the observed declines in body mass were likely a result of phenotypic plasticity. Interestingly, this plasticity was not in direct response to temperature changes but seemed to be due to changes in prey dynamics. Our results caution against interpreting recent phenotypic body size declines as adaptive evolutionary responses to temperature changes and highlight the importance of considering alternative environmental factors when testing size clines.

Place, publisher, year, edition, pages
2011. Vol. 178, no 2, 202-213 p.
Keyword [en]
animal model, climate change, heritability, Parus major, microevolution, selection
National Category
Biological Sciences
URN: urn:nbn:se:uu:diva-156939DOI: 10.1086/660834ISI: 000292917900008OAI: oai:DiVA.org:uu-156939DiVA: diva2:435856
Available from: 2011-08-20 Created: 2011-08-11 Last updated: 2011-08-20Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text
By organisation
Animal Ecology
In the same journal
American Naturalist
Biological Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 138 hits
ReferencesLink to record
Permanent link

Direct link