Olfactory Coding of Southern House Mosquito Culex quinquefasciatus to Human Odorants

Mosquito control has become the essential tool to protect human from mosquito-borne diseases. The host recognition between mosquito and human is achieved by mosquito olfactory system. Antennal sensilla, which house olfactory receptor neurons (ORNs), are responsible for detecting chemical cues from hosts. To deeply understand the mechanisms involved in the host seeking of mosquito, we conducted electrophysiological study to investigate response profile of each type of antennal sensilla to human odorants using single sensillum recording. In this study, more than one hundred human odorants have been used as stimuli to 5 subtypes of trichodea sensilla and grooved peg (GP) sensilla. The results showed that Culex quinquefasciatus (Diptera: Culicidae) only responds to a very limited number of chemicals in the human odorants. Different types of sensilla present distinctive response profiles to the human odorants tested and the responses were dose-dependent. Particularly, aldehydes generated strong responses on SST and SBTII sensilla, while amines only elicited neuronal responses on GP sensilla. Temporal dynamics of neuronal responses is both sensillum-specific and odorant-specific. Taken together, our study sheds new light on the olfactory physiology of Cx. quinquefasciatus to human odorants and provides meaningful information for developing new reagents in the mosquito control.