Figure 1

SEM depicting several CO ₂ - and octenol-sensitive maxillary palp sensilla and typical electrophysiological responses from individual sensilla to these compounds. A. Scanning electron micrograph of the distal portion of the third subsegment of the maxillary palp from a female An. stephensi (6 d post-emergence) showing s. basiconica (arrow). B. Electrophysiological response from a 21 d post-emergence female An. stephensi to a 2 s stimulation with 300 ppm CO₂. C. Electrophysiological response from a 5 d post-emergence female An. stephensi to a 2 s stimulation with 0.001 μg R-(-)-1-octen-3-ol. Since this recording was made in a background environment containing 0 ppm CO₂, the A cell is silent. Immediately following the termination of the odor stimulus, the preparation was briefly exposed to room air, resulting in a signal burst from the A neuron (arrow). Horizontal bars under the traces in panels B and C: interval (2 s) of exposure to experimental stimulus. Verticals bars in B and C represent voltages (50 μV in B and 25 μV in C).