Olfactory responses 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 able to detect chemical cues from hosts. To deeply understand the mechanisms involved in the host seeking of mosquitoes, we conducted an 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 stimulus to 5 subtypes of trichodea sensilla and grooved peg (GP) sensilla. The results showed that Cx. quinquefasciatus only responses 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, SBTI 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.