title: Zinc and cadmium hyperaccumulation act as deterrents towards specialist herbivores and impede the performance of a generalist herbivore.
abstract: Extraordinarily high leaf metal concentrations in metal hyperaccumulator plants may serve as an elemental defence against herbivores. However, mixed results have been reported and studies using comparative approaches are missing. We investigated the deterrent and toxic potential of metals employing the hyperaccumulator Arabidopsis halleri. Effects of zinc (Zn) and cadmium (Cd) on the preferences of three Brassicaceae specialists were tested in paired-choice experiments using differently treated plant material, including transgenic plants. In performance tests, we determined the toxicity and joint effects of both metals incorporated in an artificial diet on the survival of a generalist. Feeding by all specialists was significantly reduced by metal concentrations from above 1000 μg Zn g(-1) DW and 18 μg Cd g(-1) DW. By contrast, metals did not affect oviposition. Generalist survival decreased with increasing concentrations of individual metals, whereby the combination of Zn and Cd had an additive toxic effect even at the lowest applied concentrations of 100 μg Zn g(-1) and 2 μg Cd g(-1) . Metal hyperaccumulation protects plants from herbivory resulting from deterrence and toxicity against a wide range of herbivores. The combination of metals exacerbates toxicity through joint effects and enhances elemental defence. Thus, metal hyperaccumulation is ecologically beneficial for plants.
authors.affiliation: Department of Chemical Ecology, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany.
authors.forename: Ardeshir
authors.initials: A
authors.lastname: Kazemi-Dinan
authors.affiliation: Department of Chemical Ecology, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany.
authors.forename: Sina
authors.initials: S
authors.lastname: Thomaschky
authors.affiliation: Department of Plant Physiology, Ruhr University Bochum, Universitätsstr. 150, 44801, Bochum, Germany.
authors.forename: Ricardo J
authors.initials: RJ
authors.lastname: Stein
authors.affiliation: Department of Plant Physiology, Ruhr University Bochum, Universitätsstr. 150, 44801, Bochum, Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Krämer
authors.affiliation: Department of Chemical Ecology, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany.
authors.forename: Caroline
authors.initials: C
authors.lastname: Müller
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000378:metabolism*; D002104:Cadmium / Q000378:metabolism*; D060434:Herbivory; D007915:Lepidoptera; D010935:Plant Diseases; D018515:Plant Leaves / Q000378:metabolism*; D030821:Plants, Genetically Modified; D013045:Species Specificity; D015032:Zinc / Q000378:metabolism*
chemical_list: D002104:Cadmium; D015032:Zinc
keywords: Arabidopsis halleri; elemental defence hypothesis; feeding deterrence; hyperaccumulation; joint effects hypothesis; oviposition; performance; survival