Abstract: Olfaction plays a critical role in many insect behaviors. The initial steps in odor detection involve the binding of an odor to the odorant receptor displayed on dendrites of olfactory sensory neurons (OSNs). Insect OSNs express two types of odorant receptor (OR): conventional Ors, highly divergent family of receptors that are expressed in small subpopulations of OSNs; one member of Or83b family receptors，a receptor without odor sensitivity，which is expressed in the majority of OSNs and remarkably conserved across insect species. Until recently，little was known about the ligand specificity of individual conventional ORs in insect species. Or83b family proteins may facilitate trafficking of conventional ORs to the dendritic membrane of OSNs and contribute to signal transduction. Besides, there are several challenging evidences against the assumption that insect ORs belong to the family of G protein-coupled receptor (GPCR).

Key words: Insect, odorant receptors, function, olfactory sensory neurons, G proteins