title: Herbivory of an invasive slug in a model grassland community can be affected by earthworms and mycorrhizal fungi.
abstract: Invasion of non-native species is among the top threats for the biodiversity and functioning of native and agricultural ecosystems worldwide. We investigated whether the herbivory of the slugArion vulgaris(formerlyArion lusitanicus; Gastropoda), that is listed among the 100 worst alien species in Europe, is affected by soil organisms commonly present in terrestrial ecosystems (i.e. earthworms-Annelida: Lumbricidae and arbuscular mycorrhizal fungi-AMF, Glomerales). We hypothesized that slug herbivory would be affected by soil organisms via altered plant nutrient availability and plant quality. In a greenhouse experiment, we created a simple plant community consisting of a grass, a forb, and a legume species and inoculated these systems with either two earthworm species and/or four AMF taxa. Slugs were introduced after plants were established. Earthworms significantly reduced total slug herbivory in AMF-inoculated plant communities (P= 0.013). Across plant species, earthworms increased leaf total N and secondary metabolites, AMF decreased leaf thickness. Mycorrhizae induced a shift in slug feeding preference from non-legumes to legumes; the grass was generally avoided by slugs. AMF effects on legume herbivory can partly be explained by the AMF-induced increase in total N and decrease in C/N ratio; earthworm effects are less clear as no worm-induced alterations of legume plant chemistry were observed. The presence of earthworms increased average AMF colonization of plant roots by 140 % (P< 0.001). Total shoot mass was significantly increased by AMF (P< 0.001). These data suggest that the feeding behavior of this invasive slug is altered by a belowground control of plant chemical quality and community structure.
authors.affiliation: Institute of Zoology, University of Natural Resources and Life Sciences Vienna, Gregor Mendel Straße 33, 1180 Vienna, Austria ; Agro Paris Tech, Paris Institute of Technology for Life, Food and Environmental Sciences, 14 rue Girardet, CS 14216, 54042 Nancy, France.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Trouvé
authors.affiliation: Institute of Zoology, University of Natural Resources and Life Sciences Vienna, Gregor Mendel Straße 33, 1180 Vienna, Austria ; Research Institute of Organic Agriculture (FiBL Austria), Seidengasse 33-35/13, 1070 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Drapela
authors.affiliation: Institute of Zoology, University of Natural Resources and Life Sciences Vienna, Gregor Mendel Straße 33, 1180 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Frank
authors.affiliation: Albrecht-von-Haller Institute, Plant Biochemistry, Georg-August-University of Göttingen, Justus-von-Liebig Weg 11, 370077 Göttingen, Germany.
authors.forename: Franz
authors.initials: F
authors.lastname: Hadacek
authors.affiliation: Institute of Zoology, University of Natural Resources and Life Sciences Vienna, Gregor Mendel Straße 33, 1180 Vienna, Austria.
authors.forename: Johann G
authors.initials: JG
authors.lastname: Zaller
keywords: Aboveground–belowground interactions; Gastropods; Invasive species; Lumbricidae; Neobiota; Plant–soil interactions; Soil ecology; Symbiotic fungi