Fig. 1. (A) The gas chromatography-coupled single sensillum recording (GC–SSR) technique in mosquitoes. For GC, headspace extracts are injected using a microsyringe (1) onto a GC column (2). The column is situated in an oven. As the oven temperature increases, the components of the extract are separated, travel through the column and reach a split (3) from which half of the effluent goes to a flame ionization detector (FID) (4). The other half leaves the column and passes through a transfer line (5) to a glass tube (6) where a continuous humidified–purified airflow (7) blows the separated components of the extract over the mosquito antenna (8). For SSRs, two tungsten electrodes, a ground and a recording electrode (9 and 10), are placed into the eye and at the base of a single sensillum, respectively. Action potentials of the ORNs housed in a sensillum and their responses to the odor components are recorded (11).