Do you smell the danger? Effects of three commonly used pesticides on the olfactory-mediated antipredator response of zebrafish (Danio rerio) Sina N. Volz a, * , Jonas Hausen b, 1 , Kilian Smith c , Richard Ottermanns c , Andreas Schaeffer c , Sabrina Schiwy a, d , Henner Hollert a, d a Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany b Core Unit for Bioinformatics Data Analysis, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany c Chair of Environmental Biology and Chemodynamics, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany d Department of Evolutionary Ecology and Environmental Toxicology, Goethe University Frankfurt, Max-von-Laue-Str.13, 60438, Frankfurt am Main, Germany highlights graphical abstract  Pesticides alter the olfactory- mediated antipredator response of zebrafish in distinct manners.  Chlorpyrifos impairs the antipredator behavior of zebrafish.  Linuron alters the response to the conspecific skin extract.  Zebrafish avoid permethrin in a choice maze. article info Article history: Received 5 July 2019 Received in revised form 22 September 2019 Accepted 23 September 2019 Available online 26 September 2019 Handling Editor: David Volz Keywords: Antipredator response Behavior Neurotoxicity Olfaction Pesticides Zebrafish abstract Fish are warned about the presence of predators via an alarm cue released from the skin of injured conspecifics. The detection of this odor inherently initiates an antipredator response, which increases the chance of survival for the individual. In the present study, we assessed the effect of three commonly used pesticides on the antipredator response of zebrafish (Danio rerio). For this, we analyzed the behavioral response of zebrafish to a conspecific skin extract following 24 h of exposure to the respective con- taminants. Results demonstrate that fish exposed to 20 mg/L of the organophosphate insecticide chlor- pyrifos significantly reduced bottom-dwelling and freezing behavior, suggesting an impairment of the antipredator response. For the urea-herbicide linuron and the pyrethroid insecticide permethrin, no statistically significant effects could be detected. However, linuron-exposed fish appeared to respond in an altered manner to the skin extract; some individuals failed to perform the inherent behaviors such as erratic movements and instead merely increased their velocity. Furthermore, we determined whether zebrafish would avoid the pesticides in a choice maze. While fish avoided permethrin, they behaved indifferently to chlorpyrifos and linuron. The study demonstrates that pesticides may alter the olfactory- * Corresponding author. E-mail addresses: sina.volz@rwth-aachen.de (S.N. Volz), kilian.smith@bio5.rwth-aachen (K. Smith), ottermanns@bio5.rwth-aachen.de (R. Ottermanns), andreas. schaeffer@bio5.rwth-aachen.de (A. Schaeffer), schiwy@bio5.rwth-aachen.de (S. Schiwy), henner.hollert@bio5.rwth-aachen.de (H. Hollert). 1 deceased. Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere https://doi.org/10.1016/j.chemosphere.2019.124963 0045-6535/© 2019 Elsevier Ltd. All rights reserved. Chemosphere 241 (2020) 124963