title: Chemotypic variation in terpenes emitted from storage pools influences early aphid colonisation on tansy.
abstract: Tansy plants (Tanacetum vulgare L.) exhibit high chemical variation, particularly in mono- and sesquiterpenes that are stored in specialised glands on the plant surface. In the present work we investigated the effects of terpene chemotypes on Metopeurum fuscoviride, an aphid species specialised on tansy, and their tending ants, at the field scale. Previous studies have chemotyped tansy by assessing dominant compounds; here we propose a method of chemotyping using all volatile compounds that are likely emitted from the storage glands. The analysis is based on two extraction methods: GC-MS analysis of leaf hexane extracts and SBSE analysis of headspace emissions. In an initial screening we identified the subset of compounds present in both chemical patterns, labelled as 'compounds likely emitted from storage'. In a large field survey we could show that the putative chemotypic emission pattern from storage pools significantly affected the early aphid colonisation of tansy. Moreover, the statistical analyses revealed that minor compounds exerted a stronger influence on aphid and tending-ant presence than dominant compounds. Overall we demonstrated that within the enormous chemotypic variation of terpenes in tansy plants, chemical signatures of volatile terpenes can be related to the occurrence of insects on individual plants in the field.
authors.affiliation: Helmholtz Zentrum München, Institute of Biochemical Plant Pathology, Research Unit Environmental Simulation (EUS), Neuherberg, Germany.
authors.forename: Mary V
authors.initials: MV
authors.lastname: Clancy
authors.affiliation: Technische Universität München, Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management, School of Life Sciences Weihenstephan, Freising, Germany.
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Zytynska
authors.affiliation: Technische Universität München, Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management, School of Life Sciences Weihenstephan, Freising, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Senft
authors.affiliation: Technische Universität München, Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management, School of Life Sciences Weihenstephan, Freising, Germany.
authors.forename: Wolfgang W
authors.initials: WW
authors.lastname: Weisser
authors.affiliation: Helmholtz Zentrum München, Institute of Biochemical Plant Pathology, Research Unit Environmental Simulation (EUS), Neuherberg, Germany.
authors.forename: Jörg-Peter
authors.initials: JP
authors.lastname: Schnitzler
mesh_terms: D000818:Animals; D001042:Aphids / Q000502:physiology*; D008401:Gas Chromatography-Mass Spectrometry; D018515:Plant Leaves / Q000737:chemistry; D012717:Sesquiterpenes / Q000032:analysis* / Q000737:chemistry; D031203:Tanacetum / Q000737:chemistry* / Q000469:parasitology
chemical_list: D012717:Sesquiterpenes