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Birch ( Betula spp.) leaves adsorb and re‐release volatiles specific to neighbouring plants – a mechanism for associational herbivore resistance?
Author(s) -
Himanen Sari J.,
Blande James D.,
Klemola Tero,
Pulkkinen Juha,
Heijari Juha,
Holopainen Jarmo K.
Publication year - 2010
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2010.03220.x
Subject(s) - herbivore , resistance (ecology) , botany , mechanism (biology) , betula pubescens , biology , betulaceae , ecology , philosophy , epistemology
Summary• 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 C 15 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.