spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online August 17, 2007
Journal of Experimental Biology 210, 3107-3116 (2007)
Published by The Company of Biologists 2007
doi: 10.1242/jeb.007351
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplementary Material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Anderson, J. L.
Right arrow Articles by Phillips, P. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Anderson, J. L.
Right arrow Articles by Phillips, P. C.

Thermal preference of Caenorhabditis elegans: a null model and empirical tests

Jennifer L. Anderson1, Lori Albergotti1,*, Stephen Proulx2, Colin Peden1, Raymond B. Huey3 and Patrick C. Phillips1,{dagger}

1 Center for Ecology and Evolutionary Biology, University of Oregon, Eugene, OR 97402, USA
2 Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA
3 Department of Biology, University of Washington, Seattle, WA 98195, USA

{dagger} Author for correspondence (e-mail: pphil{at}uoregon.edu)

Accepted 24 June 2007

The preferred body temperature of ectotherms is typically inferred from the observed distribution of body temperatures in a laboratory thermal gradient. For very small organisms, however, that observed distribution might misrepresent true thermal preferences. Tiny ectotherms have limited thermal inertia, and so their body temperature and speed of movement will vary with their position along the gradient. In order to separate the direct effects of body temperature on movement from actual preference behaviour on a thermal gradient, we generate a null model (i.e. of non-thermoregulating individuals) of the spatial distribution of ectotherms on a thermal gradient and test the model using parameter values estimated from the movement of nematodes (Caenorhabditis elegans) at fixed temperatures and on a thermal gradient. We show that the standard lab strain N2, which is widely used in thermal gradient studies, avoids high temperature but otherwise does not exhibit a clear thermal preference, whereas the Hawaiian natural isolate CB4856 shows a clear preference for cool temperatures (~17°C). These differences are not influenced substantially by changes in the starting position of worms in the gradient, the natal temperature of individuals or the presence and physiological state of bacterial food. These results demonstrate the value of an explicit null model of thermal effects and highlight problems in the standard model of C. elegans thermotaxis, showing the value of using natural isolates for tests of complex natural behaviours.

Key words: Caenorhabditis elegans, diffusion model, natural variation, null model, thermal gradient, thermal preference






© The Company of Biologists Ltd 2007