Nicotinic Acetylcholine Receptors as Spinosyn Targets for Insect Pest Management

The spinosyns are insecticidal natural products originated from Saccharopolyspora spinosa. Spinosad, the first commercial product, is a mixture of two naturally occurring spinosyns (A & D). A second product, spinetoram, is a mixture composed of two synthetically modified spinosyns that, compared to spinosad, provides improved insecticidal potency and a broader pest insect spectrum. The spinosyns act on a subgroup of insect nicotinic acetylcholine receptors (nAChR), which are distinct from those targeted by the neonicotinoid insecticides. Selection of Drosophila for resistance to spinosad helped pinpoint the D alpha 6 as the nAChR subunit involved in the insecticidal action of the spinosyns. Cases of both target-site- and metabolism-based spinosyn resistance in insect pests in the field have been reported, and programmes have been developed to manage spinosyn resistance. This review highlights the discovery of the spinosyns, elucidation of the spinosyn target site, spinosyn-receptor interaction, and progress in spinosyn resistance management.