Birch (Betula spp.) leaves adsorb and re-release volatiles specific to neighbouring plants – a mechanism for associational herbivore resistance?
Article first published online: 10 MAR 2010
© The Authors (2010). Journal compilation © New Phytologist Trust (2010)
Volume 186, Issue 3, pages 722–732, May 2010
How to Cite
Himanen, S. J., Blande, J. D., Klemola, T., Pulkkinen, J., Heijari, J. and Holopainen, J. K. (2010), Birch (Betula spp.) leaves adsorb and re-release volatiles specific to neighbouring plants – a mechanism for associational herbivore resistance?. New Phytologist, 186: 722–732. doi: 10.1111/j.1469-8137.2010.03220.x
- Issue published online: 13 APR 2010
- Article first published online: 10 MAR 2010
- Received: 24 November 2009, Accepted: 11 January 2010
- associational resistance;
- exploitation of neighbour-emitted volatiles;
- passive volatile adsorption;
- plant–plant volatile cues;
- volatile release
- •Plant-emitted semi-volatile compounds have low vaporization rates at 20–25°C and may therefore persist on surfaces such as plant foliage. The passive adsorption of arthropod-repellent semi-volatiles to neighbouring foliage could convey associational resistance, whereby a plant’s neighbours reduce damage caused by herbivores.
- •We found that birch (Betula spp.) leaves adsorb and re-release the specific arthropod-repelling C15 semi-volatiles ledene, ledol and palustrol produced by Rhododendron tomentosum when grown in mixed association in a field setup. In a natural habitat, a higher concentration of ledene was released from birches neighbouring R. tomentosum than from birches situated > 5 m from R. tomentosum. Emission of α-humulene, a sesquiterpene synthesized by both Betula pendula and R. tomentosum, was also increased in R. tomentosum-neighbouring B. pendula.
- •In assessments for associational resistance, we found that the polyphagous green leaf weevils (Polydrusus flavipes) and autumnal moth (Epirrita autumnata) larvae both preferred B. pendula to R. tomentosum. P. flavipes also preferred birch leaves not exposed to R. tomentosum to leaves from mixed associations. In the field, a reduction in Euceraphis betulae aphid density occurred in mixed associations.
- •Our results suggest that plant/tree species may be protected by semi-volatile compounds emitted by a more herbivore-resistant heterospecific neighbour.