Odorant coreceptor which complexes with conventional odorant receptors (ORs) to form odorant-sensing units, providing sensitive and prolonged odorant signaling and calcium permeability (By similarity). Obligate coreceptor of all odorant receptors (By similarity). Orco is a universal and integral part of the functional odorant receptor, involved in the dendritic localization of other olfactory receptors. Can form functional ion channels in the absence of an odor-binding odorant receptor (By similarity). Plays a central role in the perception of olfactory stimuli in ants and is essential for ant social organization (PubMed:28802042). Required for pheromone sensing (PubMed:28802042). Also required for the development and maintenance of odorant receptor neurons (ORNs) and of antennal lobe glomeruli (PubMed:28802042). Heterodimer with conventional odorant receptors (ORs). Present in antennae (at protein level). Impaired behavior and fitness, probably due to loss of pheromone sensing. Ants also display gross neuroanatomical defects in the antennal lobe, with a dramatic decrease in the number of antennal lobe glomeruli. In contrast to other ant species, C.biroi ants reproduce via parthenogenesis, enabling stable germline modifications from the clonal progeny of injected individuals without laboratory crosses. Belongs to the insect chemoreceptor superfamily. Heteromeric odorant receptor channel (TC 1.A.69) family. Orco subfamily. Whispers - Issue 197 of November 2017