Electrophysiological response of the olfactory sensilla to human odorants in the common bed bug, Cimex lectularius

Human odorants were considered to be very important cues in the host-seeking process of the blood-feeding insects. For the common bed bug, Cimex lectularius, which is a temporary ectoparasite on humans and currently resurgent in the developed countries, the host-seeking behavior is critical for them to survive and reproduce. The olfactory system of the bed bugs plays an important role in detecting the human odorants in the environment. To gain insight into the interaction between the bed bug’s olfactory system and the human odorants, we, for the first time, investigated electrophysiological response of olfactory sensilla in the common bed bugs to 104 human odorants. The result showed that different types of sensilla displayed very distinctive response profiles to the human odorants. Particularly, the D sensilla of the common bed bugs were found to be extremely sensitive to the aldehydes and aromatics, C sensilla were very sensitive to the amines while the E sensilla didn’t show very strong response to most of the human odorants.  The functional study, using Xenopus oocytes expression system, revealed that olfactory receptors in the olfactory receptor neurons were playing the essential role in the response of the common bed bugs to human odorants.  Taken together, our study not only enables us to better understand the bed bug olfactory system but also provides insight into the molecular basis of the olfactory response to human odorants - the valuable information for developing new attractants or repellents in the bed bug and/or insect control.