| Title: | Inducibility of chemical defenses in Norway spruce bark is correlated with unsuccessful mass attacks by the spruce bark beetle |
| Author(s): | Schiebe C; Hammerbacher A; Birgersson G; Witzell J; Brodelius PE; Gershenzon J; Hansson BS; Krokene P; Schlyter F; |
| Address: | "Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, PO Box 102, 230 53, Alnarp, Sweden. christian.schiebe@slu.se" |
| DOI: | 10.1007/s00442-012-2298-8 |
| ISSN/ISBN: | 1432-1939 (Electronic) 0029-8549 (Linking) |
| Abstract: | "Secondary attraction to aggregation pheromones plays a central role in the host colonization behavior of the European spruce bark beetle Ips typographus. However, it is largely unknown how the beetles pioneering an attack locate suitable host trees, and eventually accept or reject them. To find possible biomarkers for host choice by I. typographus, we analyzed the chemistry of 58 Norway spruce (Picea abies) trees that were subsequently either (1) successfully attacked and killed, (2) unsuccessfully attacked, or (3) left unattacked. The trees were sampled before the main beetle flight in a natural Norway spruce-dominated forest. No pheromones were used to attract beetles to the experimental trees. To test the trees' defense potential, each tree was treated in a local area with the defense hormone methyl jasmonate (MeJ), and treated and untreated bark were analyzed for 66 different compounds, including terpenes, phenolics and alkaloids. The chemistry of MeJ-treated bark correlated strongly with the success of I. typographus attack, revealing major chemical differences between killed trees and unsuccessfully attacked trees. Surviving trees produced significantly higher amounts of most of the 39 analyzed mono-, sesqui-, and diterpenes and of 4 of 20 phenolics. Alkaloids showed no clear pattern. Differences in untreated bark were less pronounced, where only 1,8-cineole and (-)-limonene were significantly higher in unsuccessfully attacked trees. Our results show that the potential of individual P. abies trees for inducing defense compounds upon I. typographus attack may partly determine tree resistance to this bark beetle by inhibiting its mass attack" |
| Keywords: | "*Adaptation, Physiological Animals Biomarkers/analysis Coleoptera Herbivory Phenols/metabolism Pheromones/analysis Picea/*chemistry/growth & development Plant Bark/chemistry Plants, Edible/*chemistry Survival Terpenes/metabolism;" |
| Notes: | "MedlineSchiebe, Christian Hammerbacher, Almuth Birgersson, Goran Witzell, Johanna Brodelius, Peter E Gershenzon, Jonathan Hansson, Bill S Krokene, Paal Schlyter, Fredrik eng Research Support, Non-U.S. Gov't Germany 2012/03/17 Oecologia. 2012 Sep; 170(1):183-98. doi: 10.1007/s00442-012-2298-8. Epub 2012 Mar 16" |
