title: Delayed and time-cumulative toxicity of imidacloprid in bees, ants and termites.
abstract: Imidacloprid, one of the most commonly used insecticides, is highly toxic to bees and other beneficial insects. The regulatory challenge to determine safe levels of residual pesticides can benefit from information about the time-dependent toxicity of this chemical. Using published toxicity data for imidacloprid for several insect species, we construct time-to-lethal-effect toxicity plots and fit temporal power-law scaling curves to the data. The level of toxic exposure that results in 50% mortality after time t is found to scale as t(1.7) for ants, from t(1.6) to t(5) for honeybees, and from t(1.46) to t(2.9) for termites. We present a simple toxicological model that can explain t(2) scaling. Extrapolating the toxicity scaling for honeybees to the lifespan of winter bees suggests that imidacloprid in honey at 0.25 μg/kg would be lethal to a large proportion of bees nearing the end of their life.
authors.affiliation: Applied Scientific Instumentation, 1025 Elkay Drive, Eugene, Oregon 97405, USA.
authors.forename: Gary
authors.initials: G
authors.lastname: Rondeau
authors.affiliation: University of Sydney, Faculty of Agriculture & Environment, 1 Central Avenue, Eveleigh, NSW 2015, Australia.
authors.forename: Francisco
authors.initials: F
authors.lastname: Sánchez-Bayo
authors.affiliation: Experimental Toxicology Services (ETS) Nederland BV, Frankensteeg 4, Zutphen, 7201 KN, The Netherlands.
authors.forename: Henk A
authors.initials: HA
authors.lastname: Tennekes
authors.affiliation: Association de Coordination Technique Agricole (ACTA), ITSAP-Institut de l'Abeille, UMT PrADE, Site Agroparc, 84914 Avignon, France.
authors.forename: Axel
authors.initials: A
authors.lastname: Decourtye
authors.affiliation: Departamento de Producción Agrícola, Universidad de Guadalajara, Zapopan, Jalisco, Mexico.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Ramírez-Romero
authors.affiliation: French National Institute for Agricultural Research (INRA), Institut Sophia Agrobiotech, 400 route des chappes, 06903 Sophia-Antipolis, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Desneux
mesh_terms: D000818:Animals; D001000:Ants / Q000187:drug effects*; D001516:Bees / Q000187:drug effects*; D007093:Imidazoles / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D020049:Isoptera / Q000187:drug effects*; D007814:Larva / Q000187:drug effects; D007928:Lethal Dose 50; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000633:toxicity*
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C082359:imidacloprid