title: Neonicotinoid-induced impairment of odour coding in the honeybee.
abstract: Exposure to neonicotinoid pesticides is considered one of the possible causes of honeybee (Apis mellifera) population decline. At sublethal doses, these chemicals have been shown to negatively affect a number of behaviours, including performance of olfactory learning and memory, due to their interference with acetylcholine signalling in the mushroom bodies. Here we provide evidence that neonicotinoids can affect odour coding upstream of the mushroom bodies, in the first odour processing centres of the honeybee brain, i.e. the antennal lobes (ALs). In particular, we investigated the effects of imidacloprid, the most common neonicotinoid, in the AL glomeruli via in vivo two-photon calcium imaging combined with pulsed odour stimulation. Following acute imidacloprid treatment, odour-evoked calcium response amplitude in single glomeruli decreases, and at the network level the representations of different odours are no longer separated. This demonstrates that, under neonicotinoid influence, olfactory information might reach the mushroom bodies in a form that is already incorrect. Thus, some of the impairments in olfactory learning and memory caused by neonicotinoids could, in fact, arise from the disruption in odor coding and olfactory discrimination ability of the honey bees.
authors.affiliation: Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy.
authors.forename: Mara
authors.initials: M
authors.lastname: Andrione
authors.affiliation: Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Vallortigara
authors.affiliation: Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy.|Department of Physics, University of Trento, Trento, Italy.
authors.forename: Renzo
authors.initials: R
authors.lastname: Antolini
authors.affiliation: Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy.|Department of Physics, University of Trento, Trento, Italy.
authors.forename: Albrecht
authors.initials: A
authors.lastname: Haase
mesh_terms: D000818:Animals; D001516:Bees / Q000187:drug effects* / Q000502:physiology*; D020013:Calcium Signaling / Q000187:drug effects; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D007306:Insecticides / Q000633:toxicity*; D007858:Learning / Q000187:drug effects / Q000502:physiology; D008568:Memory / Q000187:drug effects / Q000502:physiology; D024521:Mushroom Bodies / Q000187:drug effects / Q000502:physiology; D000073943:Neonicotinoids / Q000633:toxicity*; D009574:Nitro Compounds / Q000633:toxicity; D009812:Odorants; D018034:Olfactory Receptor Neurons / Q000187:drug effects / Q000502:physiology; D012903:Smell / Q000187:drug effects* / Q000502:physiology*
chemical_list: D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C082359:imidacloprid