Abstract
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.
Highlights
In nearly 30 years since their first introduction, neonicotinoids have become the world’s most widely used insecticides [1]
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
Scientific studies reveal the high complexity of the cholinergic system, which renders the prediction of neural responses to various levels of neonicotinoid exposure difficult
Summary
In nearly 30 years since their first introduction, neonicotinoids have become the world’s most widely used insecticides [1]. When binding to nAchRs, neonicotinoids induce neuronal depolarisation and temporarily prevent the action of acetylcholine [11,13] This results, e.g., in altered olfactory learning and memory abilities, which were shown to depend on cholinergic signalling [14,15]. In bees living in treated agricultural areas, neurons expressing nAchRs are stimulated by the neonicotinoids present in the nectar and pollen consumed [9]. This might trigger both activity-dependent synaptic plasticity and homeostatic plasticity, which maintains the stability of the neural network, as demonstrated in other species [16,17]. By providing a summary of the literature on the neonicotinoid impact on honeybee brain, we aim at highlighting the current knowledge gaps, thereby orienting future research in this field
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
