Journal of Chemical Ecology

, Volume 42, Issue 2, pp 127-138

First online:

Measurements of Chlorpyrifos Levels in Forager Bees and Comparison with Levels that Disrupt Honey Bee Odor-Mediated Learning Under Laboratory Conditions

  • Elodie UrlacherAffiliated withUniversity of Otago, Department of Zoology Email author 
  • , Coline MonchaninAffiliated withUniversity of Otago, Department of Zoology
  • , Coraline RivièreAffiliated withUniversity of Otago, Department of Zoology
  • , Freddie-Jeanne RichardAffiliated withLaboratoire Ecologie et Biologie des intéractions, UMR CNRS 7267, Team Ecologie Evolution Symbiose, University of Poitiers
  • , Christie LombardiAffiliated withDepartment of Chemistry, University of Otago
  • , Sue Michelsen-HeathAffiliated withUniversity of Otago, Department of Zoology
  • , Kimberly J. HagemanAffiliated withDepartment of Chemistry, University of Otago
  • , Alison R. MercerAffiliated withUniversity of Otago, Department of Zoology

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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.


Chlorpyrifos Honey bee Appetitive learning Memory specificity Field measurements