title: Measurements of Chlorpyrifos Levels in Forager Bees and Comparison with Levels that Disrupt Honey Bee Odor-Mediated Learning Under Laboratory Conditions.
abstract: Chlorpyrifos is an organophosphate pesticide used around the world to protect food crops against insects and mites. Despite guidelines for chlorpyrifos usage, including precautions to protect beneficial insects, such as honeybees from spray drift, this pesticide has been detected in bees in various countries, indicating that exposure still occurs. Here, we examined chlorpyrifos levels in bees collected from 17 locations in Otago, New Zealand, and compared doses of this pesticide that cause sub-lethal effects on learning performance under laboratory conditions with amounts of chlorpyrifos detected in the bees in the field. The pesticide was detected at 17 % of the sites sampled and in 12 % of the colonies examined. Amounts detected ranged from 35 to 286 pg.bee(-1), far below the LD50 of ~100 ng.bee(-1). We detected no adverse effect of chlorpyrifos on aversive learning, but the formation and retrieval of appetitive olfactory memories was severely affected. Chlorpyrifos fed to bees in amounts several orders of magnitude lower than the LD50, and also lower than levels detected in bees, was found to slow appetitive learning and reduce the specificity of memory recall. As learning and memory play a central role in the behavioral ecology and communication of foraging bees, chlorpyrifos, even in sublethal doses, may threaten the success and survival of this important insect pollinator.
authors.affiliation: University of Otago, Department of Zoology, 340 Great King Street PO Box 56, Dunedin, 9054, New Zealand. elodie.urlacher@otago.ac.nz.
authors.forename: Elodie
authors.initials: E
authors.lastname: Urlacher
authors.affiliation: University of Otago, Department of Zoology, 340 Great King Street PO Box 56, Dunedin, 9054, New Zealand.
authors.forename: Coline
authors.initials: C
authors.lastname: Monchanin
authors.affiliation: University of Otago, Department of Zoology, 340 Great King Street PO Box 56, Dunedin, 9054, New Zealand.
authors.forename: Coraline
authors.initials: C
authors.lastname: Rivière
authors.affiliation: Laboratoire Ecologie et Biologie des intéractions, UMR CNRS 7267, Team Ecologie Evolution Symbiose, University of Poitiers, 6, rue Michel Brunet, TSA 51106, F-86073, Poitiers Cedex 9, France.
authors.forename: Freddie-Jeanne
authors.initials: FJ
authors.lastname: Richard
authors.affiliation: Department of Chemistry, University of Otago, Union Street West, PO Box 56, Dunedin, 9054, New Zealand.
authors.forename: Christie
authors.initials: C
authors.lastname: Lombardi
authors.affiliation: University of Otago, Department of Zoology, 340 Great King Street PO Box 56, Dunedin, 9054, New Zealand.
authors.forename: Sue
authors.initials: S
authors.lastname: Michelsen-Heath
authors.affiliation: Department of Chemistry, University of Otago, Union Street West, PO Box 56, Dunedin, 9054, New Zealand.
authors.forename: Kimberly J
authors.initials: KJ
authors.lastname: Hageman
authors.affiliation: University of Otago, Department of Zoology, 340 Great King Street PO Box 56, Dunedin, 9054, New Zealand.
authors.forename: Alison R
authors.initials: AR
authors.lastname: Mercer
mesh_terms: D000818:Animals; D001516:Bees / Q000378:metabolism* / Q000502:physiology; D001522:Behavior, Animal; D004390:Chlorpyrifos / Q000378:metabolism* / Q000494:pharmacology; D007306:Insecticides / Q000494:pharmacology*; D007858:Learning / Q000187:drug effects*; D009812:Odorants
chemical_list: D007306:Insecticides; D004390:Chlorpyrifos
keywords: Appetitive learning; Chlorpyrifos; Field measurements; Honey bee; Memory specificity