Odorant receptor which mediates acceptance or avoidance behavior, depending on its substrates. The odorant receptor repertoire encodes a large collection of odor stimuli that vary widely in identity, intensity, and duration. May form a complex with Orco to form odorant-sensing units, providing sensitive and prolonged odorant signaling and calcium permeability (By similarity). Interacts with Orco. Complexes exist early in the endomembrane system in olfactory sensory neurons (OSNs), coupling these complexes to the conserved ciliary trafficking pathway (By similarity). Expressed in 15% of the 120 sensory neurons within the maxillary palp. The atypical heteromeric and topological design of the odorant receptors appears to be an insect-specific solution for odor recognition, making the OR/Orco complex an attractive target for the development of highly selective insect repellents to disrupt olfactory-mediated host-seeking behaviors of insect disease vectors. Odor-evoked OR currents are independent of known G-protein-coupled second messenger pathways. Belongs to the insect chemoreceptor superfamily. Heteromeric odorant receptor channel (TC 1.A.69) family. Or2a subfamily. The strain (Berkeley) sequenced by the collaborative genome project contains a 3' deletion and is considered a pseudogene.