Table 1.

Neuronal plasticity associated with chronic oral exposure to neonicotinoids in adult honeybees (* not European honeybees). Field-realistic doses based on [50] are highlighted in grey. nAchR: nicotinic acetylcholine receptor.

	Reference	Neonicotinoid	Treatment Duration	Minimal Dose	Effects
Gene Expression	[46]	Acetamiprid	24 h, 48 h, 72 h	80,000 ppb	Increased expression of nAchRα1 after 72 h
		Clothianidin		0.3 ppb	Increased expression of nAchRα1 after 72 h
		Imidacloprid		3 ppb	Increased expression of nAchRα1 after 72 h
				3 ppb	Increased expression of nAchRα2 after 48 h, but not after 72 h
		Thiametoxam		1 ppb	Increased expression of nAchRα1 after 48 h
				10 ppb	Increased expression of nAchRα1 after 72 h
				1 ppb	Increased expression of nAchRα2 after 48 h, but not after 72 h
	[47]	Thiametoxam	10 days	10 ppb	225 upregulated genes, 384 downregulated genes
					Increased expression of nAchRα9 and nAchRβ2
	[35] *	Acetamiprid	0.5 h, 1 h, 2 h, 3 h	10,000 ppb	Increased expression of nAchRβ1 and nAchRβ2 at 0.5 h
		Imidacloprid	1 h, 2 h, 3 h, 4 h	10,000 ppb	Decreased expression of nAchRβ1 and nAchRβ2 at 1–2 h
Neuronal	[51]	Imidacloprid	Larval stage (effects	10 ppb	Decreased synaptic bouton density in the MB lateral calyces
Structure			20 days after eclosion)	100 ppb	Decreased synaptic bouton density in the MB median calyces
	[52] *	Imidacloprid	1, 3, 5, 7 or 10 days	800 ppb	Increased cell death after 1 day in the optic lobes
				8100 ppb	Increased cell death after 1 day in the mushroom bodies
	[53]	Imidacloprid	1, 4, 8 days	14.6 ppb	Cellular alterations (mitochondria, chromatin, phagosomes)