The intensive use of insecticides, combined with other factors such as habitat loss, might explain worldwide decrease of insect populations documented in the past twenty years. However, due to the involvement of pest species in crop destruction and in vector‐borne diseases, insecticides will probably continue to be required still for decades. The most commercially successful insecticides are neurotoxicants acting on ion channels of the central nervous system affecting thereby cellular excitability and synaptic transmission and causing insect paralysis and fatality. In this article, we provide an overview of the insecticides acting on voltage‐gated sodium channels, GABA‐gated chloride channels and nicotinic acetylcholine receptors. We summarize the current knowledge on those ion channels from the honeybee Apis mellifera and discuss the possible mode of action of neurotoxic insecticides.

The number of insect GABA receptors (GABAr) available for expression studies has been recently increased by the cloning of the Acyrthosiphon pisum (pea aphid) RDL subunits. This large number of cloned RDL subunits from pest and beneficial insects opens the door to parallel pharmacological studies on the sensitivity of these different insect GABAr to various agonists or antagonists. The resulting analysis of the molecular basis of the species-specific GABAr responses to insecticides is necessary not only to depict and understand species toxicity, but also to help at the early identification of unacceptable toxicity of insecticides toward beneficial insects such as Apis mellifera (honeybees). Using heterologous expression in Xenopus laevis oocytes, and two-electrode voltage-clamp recording to assess the properties of the GABAr, we performed a comparative analysis of the pharmacological sensitivity of RDL subunits from A. pisum, A. mellifera and Varroa destructor GABAr to three pesticides (fipronil, picrotoxin and dieldrin). These data were compared to similar characterizations performed on two Homo sapiens GABA-A receptors (α2β2γ2 and α2β2γ2). Our results underline a global conservation of the pharmacological profiles of these receptors, with some interesting species specificities, nonetheless, and suggest that this approach can be useful for the early identification of poorly specific molecules.