title: Intraspecific differences in plant chemotype determine the structure of arthropod food webs.
abstract: It is becoming increasingly appreciated that the structure and functioning of ecological food webs are controlled by the nature and level of plant chemicals. It is hypothesized that intraspecific variation in plant chemical resistance, in which individuals of a host-plant population exhibit genetic differences in their chemical contents (called 'plant chemotypes'), may be an important determinant of variation in food web structure and functioning. We evaluated this hypothesis using field assessments and plant chemical assays in the tansy plant Tanacetum vulgare L. (Asteraceae). We examined food webs in which chemotypes of tansy plants are the resource for two specialized aphids, their predators and mutualistic ants. The density of the ant-tended aphid Metopeurum fuscoviride was significantly higher on particular chemotypes (borneol) than others. Clear chemotype preferences between predators were also detected. Aphid specialist seven-spotted ladybird beetles (Coccinella septempunctata) were more often found on camphor plants, while significantly higher numbers of the polyphagous nursery web spider (Pisaura mirabilis) were observed on borneol plants. The analysis of plant chemotype effects on the arthropod community clearly demonstrates a range of possible outcomes between plant-aphid-predator networks. The findings help to offer a deeper insight into how one important factor--plant chemical content--influences which species coexist within a food web on a particular host plant and the nature of their trophic linkages.
authors.affiliation: Department of Horticulture, Faculty of Technical and Human Science, Sapientia University, Sighisoara Street 1C, Tirgu-Mures, Romania.
authors.forename: János
authors.initials: J
authors.lastname: Bálint
authors.affiliation: Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management, Centre for Food and Life Sciences Weihenstephan, Technische Universität München, Freising-Weihenstephan, Germany.
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Zytynska
authors.affiliation: Department of Food Science, Faculty of Technical Science, Sapientia University, Miercurea Ciuc, Romania.
authors.forename: Rozália Veronika
authors.initials: RV
authors.lastname: Salamon
authors.affiliation: Department of Biodiversity, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Mehrparvar
authors.affiliation: Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management, Centre for Food and Life Sciences Weihenstephan, Technische Universität München, Freising-Weihenstephan, Germany.
authors.forename: Wolfgang W
authors.initials: WW
authors.lastname: Weisser
authors.affiliation: School of Forestry and Environmental Studies, Yale University, 370 Prospect Street, New Haven, Connecticut, USA.
authors.forename: Oswald J
authors.initials: OJ
authors.lastname: Schmitz
authors.affiliation: Department of Horticulture, Faculty of Technical and Human Science, Sapientia University, Sighisoara Street 1C, Tirgu-Mures, Romania. benedekklara@ms.sapientia.ro.
authors.forename: Klára
authors.initials: K
authors.lastname: Benedek
authors.affiliation: Department of Horticulture, Faculty of Technical and Human Science, Sapientia University, Sighisoara Street 1C, Tirgu-Mures, Romania. adalbert.balog@fulbrightmail.org.
authors.forename: Adalbert
authors.initials: A
authors.lastname: Balog
mesh_terms: D000818:Animals; D001000:Ants; D001042:Aphids; D001892:Camphanes; D001517:Coleoptera; D020387:Food Chain; D007313:Insecta; D010641:Phenotype; D011235:Predatory Behavior; D013112:Spiders; D013559:Symbiosis; D031203:Tanacetum / Q000737:chemistry*
chemical_list: D001892:Camphanes; C022871:isoborneol
keywords: Aphids Ants; Bottom-up effects; Interactions; Predation; Top-down effects