title: Pesticide exposure and inducible antipredator responses in the zooplankton grazer, Daphnia magna Straus.
abstract: Risk assessment of toxic substances under ecologically-relevant scenarios which include the presence of natural stressors is essential to understand their indirect toxic effects and to improve prediction of the impacts of contamination on community structure and ecosystem function. Here, we study the effects of the pesticide imidacloprid on the responses of Daphnia magna to a combination of predator-release kairomones from trout and alarm cues from conspecifics, simulating different levels of perceived predation risk. The joint effects of simultaneous exposure to both types of stressors were assessed both by traditional analysis of variance and by employing conceptual models for the evaluation of contaminant mixture exposures. Results demonstrated that pesticide exposure can significantly increase the costs of inducible antipredator defences and impair life-history responses of daphnids to fish predation pressure. Since trait-mediated effects are well-known to play a key role in population dynamics, the combined direct and indirect effects of sub-lethal concentrations of pesticides could induce maladaptive responses in zooplankton populations in the field, reducing their long-term viability.
authors.affiliation: CESAM and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal. jpestana@ua.pt
authors.forename: João L T
authors.initials: JL
authors.lastname: Pestana
authors.forename: Susana
authors.initials: S
authors.lastname: Loureiro
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Baird
authors.forename: Amadeu M V M
authors.initials: AM
authors.lastname: Soares
mesh_terms: D000818:Animals; D003621:Daphnia / Q000187:drug effects* / Q000378:metabolism; D005247:Feeding Behavior / Q000187:drug effects; D020387:Food Chain; D007093:Imidazoles / Q000633:toxicity*; D008018:Life Cycle Stages / Q000187:drug effects; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000633:toxicity*; D010101:Oxygen Consumption / Q000187:drug effects; D010575:Pesticides / Q000633:toxicity*; D010675:Pheromones / Q000494:pharmacology; D011235:Predatory Behavior / Q000187:drug effects; D023382:Toxicity Tests, Acute; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015048:Zooplankton
chemical_list: D007093:Imidazoles; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010575:Pesticides; D010675:Pheromones; D014874:Water Pollutants, Chemical; C082359:imidacloprid