Neonicotinoids disrupt memory, circadian behaviour and sleep, Tasman et al

Globally, neonicotinoids are the most used insecticides, despite their well-documented sublethal effects on beneficial insects. Neonicotinoids are nicotinic acetylcholine receptor agonists.
Memory, circadian rhythmicity and sleep are essential for efficient foraging and pollination and
require nicotinic acetylcholine receptor signalling. The effect of field-relevant concentrations of the
European Union-banned neonicotinoids: imidacloprid, clothianidin, thiamethoxam and thiacloprid
were tested on Drosophila memory, circadian rhythms and sleep. Field-relevant concentrations of
imidacloprid, clothianidin and thiamethoxam disrupted learning, behavioural rhythmicity and sleep
whilst thiacloprid exposure only affected sleep. Exposure to imidacloprid and clothianidin prevented
the day/night remodelling and accumulation of pigment dispersing factor (PDF) neuropeptide in
the dorsal terminals of clock neurons. Knockdown of the neonicotinoid susceptible Dα1 and Dβ2
nicotinic acetylcholine receptor subunits in the mushroom bodies or clock neurons recapitulated the
neonicotinoid like deficits in memory or sleep/circadian behaviour respectively. Disruption of learning,
circadian rhythmicity and sleep are likely to have far-reaching detrimental effects on beneficial insects
in the field.