title: Sublethal effects of imidacloprid on interactions in a tritrophic system of non-target species.
abstract: Imidacloprid is one of the most used insecticides worldwide, but is highly toxic to non-target arthropods. Effects of sublethal imidacloprid intoxication can potentially propagate in food webs, yet little is known about the impact on non-target populations and communities. We investigated short-term sublethal toxicity of imidacloprid in a tritrophic model system of wild strawberry Fragaria vesca, wood cricket Nemobius sylvestris and nursery web spider Pisaura mirabilis. Strawberries were treated two times with 0mg (control), 1mg (low rate) and 10mg (high rate) of Confidor® WG 70 and crickets were allowed to feed on them. In four lab experiments, we quantified the impact of imidacloprid on leaf damage, growth, behaviour and survival of crickets. The high imidacloprid rate reduced feeding, mass gain, thorax growth and mobility in crickets compared to the control, while mortality was similarly low in all treatments. The low rate reduced mass gain only. Cricket survival of spider predation was higher in the low rate treatment than in the control. Overall, herbivory and predation were reduced at sublethal imidacloprid rates in a non-target organism, three-level food chain, which demonstrates possible propagation of sublethal effects through trophic interactions.
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany. Electronic address: uhl@uni-landau.de.
authors.forename: Philipp
authors.initials: P
authors.lastname: Uhl
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany.
authors.forename: Roman
authors.initials: R
authors.lastname: Bucher
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany.
authors.forename: Ralf B
authors.initials: RB
authors.lastname: Schäfer
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany.
authors.forename: Martin H
authors.initials: MH
authors.lastname: Entling
mesh_terms: D000818:Animals; D020387:Food Chain; D031985:Fragaria / Q000187:drug effects*; D006135:Gryllidae / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D007093:Imidazoles / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000633:toxicity*; D018515:Plant Leaves / Q000187:drug effects; D011235:Predatory Behavior / Q000187:drug effects; D013112:Spiders / Q000187:drug effects* / Q000502:physiology
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C082359:imidacloprid
keywords: Fragaria vesca; Nemobius sylvestris; Neonicotinoids; Pisaura mirabilis; Sublethal toxicity; Trait-mediated effects