Silencing the odorant receptor co-receptor impairs olfactory reception in a sensillum-specific manner in the cockroach.

Insects detect odors via a large variety of odorant receptors (ORs) expressed in olfactory sensory neurons (OSNs). The insect OR is a heteromeric complex composed of a ligand-specific receptor and the co-receptor (ORco). In this study, we identified the gene of the cockroach, (), and performed RNAi-based functional analysis of . All OSNs in the basiconic sensilla expressed ORco and received a large variety of odors including sex pheromones. In trichoid sensilla, a ORco-positive OSN was consistently paired with a ORco-negative OSN tuned to acids. In adult cockroaches injected with dsRNA at the nymphal stage, the expression of , odor receptions via ORs, and its central processing were strongly suppressed. These results provide new insights into the molecular basis of olfactory reception in the cockroach. The long-lasting and irreversible effects of RNAi would be an effective method for controlling the household pest.