The Neurophysiological Bases of the Impact of Neonicotinoid Pesticides on the Behaviour of Honeybees
Center for Mind/Brain Sciences (CIMeC), University of Trento, piazza Manifattura 1, 38068 Rovereto, Italy
Department of Physics, University of Trento, via Sommarive 14, 38123 Povo, Italy
Authors to whom correspondence should be addressed.
Insects 2019, 10(10), 344; https://doi.org/10.3390/insects10100344
Received: 6 September 2019 / Revised: 4 October 2019 / Accepted: 6 October 2019 / Published: 14 October 2019
(This article belongs to the Special Issue Honeybee Neurobiology and Behavior)
Acetylcholine is the main excitatory neurotransmitter in the honeybee brain and controls a wide range of behaviours that ensure the survival of the individuals and of the entire colony. Neonicotinoid pesticides target this neurotransmission pathway and can thereby affect the behaviours under its control, even at doses far below the toxicity limit. These sublethal effects of neonicotinoids on honeybee behaviours were suggested to be partly responsible for the decline in honeybee populations. However, the neural mechanisms by which neonicotinoids influence single behaviours are still unclear. This is mainly due to the heterogeneity of the exposure pathways, doses and durations between studies. Here, we provide a review of the state of the science in this field and highlight knowledge gaps that need to be closed. We describe the agonistic effects of neonicotinoids on neurons expressing the different nicotinic acetylcholine receptors and the resulting brain structural and functional changes, which are likely responsible for the behavioural alterations reported in bees exposed to neonicotinoids.