Chronic exposure to trace lead impairs honey bee learning.

Affiliation

Monchanin C(1), Blanc-Brude A(2), Drujont E(2), Negahi MM(2), Pasquaretta C(2), Silvestre J(3), Baqué D(3), Elger A(3), Barron AB(4), Devaud JM(2), Lihoreau M(5).
Author information:
(1)Research Center on Animal Cognition
(CRCA), Center for Integrative Biology
(CBI); CNRS, University Paul Sabatier - Toulouse III, France; Department of Biological Sciences, Macquarie University, NSW, Australia. Electronic address: [Email]
(2)Research Center on Animal Cognition
(CRCA), Center for Integrative Biology
(CBI); CNRS, University Paul Sabatier - Toulouse III, France.
(3)EcoLab, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France.
(4)Department of Biological Sciences, Macquarie University, NSW, Australia.
(5)Research Center on Animal Cognition
(CRCA), Center for Integrative Biology
(CBI); CNRS, University Paul Sabatier - Toulouse III, France. Electronic address: [Email]

Abstract

Pollutants can have severe detrimental effects on insects, even at sublethal doses, damaging developmental and cognitive processes involved in crucial behaviours. Agrochemicals have been identified as important causes of pollinator declines, but the impacts of other anthropogenic compounds, such as metallic trace elements in soils and waters, have received considerably less attention. Here, we exposed colonies of the European honey bee Apis mellifera to chronic field-realistic concentrations of lead in food and demonstrated that consumption of this trace element impaired bee cognition and morphological development. Honey bees exposed to the highest of these low concentrations had reduced olfactory learning performances. These honey bees also developed smaller heads, which may have constrained their cognitive functions as we show a general relationship between head size and learning performance. Our results demonstrate that lead pollutants, even at trace levels, can have dramatic effects on honey bee cognitive abilities, potentially altering key colony functions and the pollination service.