GLOBAL PATTERNS OF LEAF DEFENSES IN OAK SPECIES
Article first published online: 3 MAR 2012
© 2012 The Author(s).
Volume 66, Issue 7, pages 2272–2286, July 2012
How to Cite
Pearse, I. S. and Hipp, A. L. (2012), GLOBAL PATTERNS OF LEAF DEFENSES IN OAK SPECIES. Evolution, 66: 2272–2286. doi: 10.1111/j.1558-5646.2012.01591.x
- Issue published online: 3 JUL 2012
- Article first published online: 3 MAR 2012
- Accepted manuscript online: 3 FEB 2012 02:51PM EST
- Received May 24, 2011, Accepted January 17, 2012, Data Archived: Dryad doi:10.5061/dryad.336n3gt0
- Ornstein–Uhlenbeck model;
- plant–insect interaction;
Plant defensive traits drive patterns of herbivory and herbivore diversity among plant species. Over the past 30 years, several prominent hypotheses have predicted the association of plant defenses with particular abiotic environments or geographic regions. We used a strongly supported phylogeny of oaks to test whether defensive traits of 56 oak species are associated with particular components of their climatic niche. Climate predicted both the chemical leaf defenses and the physical leaf defenses of oaks, whether analyzed separately or in combination. Oak leaf defenses were higher at lower latitudes, and this latitudinal gradient could be explained entirely by climate. Using phylogenetic regression methods, we found that plant defenses tended to be greater in oak species that occur in regions with low temperature seasonality, mild winters, and low minimum precipitation, and that plant defenses may track the abiotic environment slowly over macroevolutionary time. The pattern of association we observed between oak leaf traits and abiotic environments was consistent with a combination of a seasonality gradient, which may relate to different herbivore pressures, and the resource availability hypothesis, which posits that herbivores exert greater selection on plants in resource-limited abiotic environments.