Fig. 3.

Analysis of bird- and human-derived odorants by GC-EAD. (A) A live nonbloodfed Cx. quinquefasciatus female was fixed in a truncated pipette tip and secured by modeling clay letting only the eyes and antenna exposed. (Inset) Ground electrode impaled in the eye and two antennae inserted into the recording electrode. Antennal responses to (B) chicken odorants collected on SuperQ polymer and fractionated by gas chromatography and (C) a synthetic mixture containing 50 ng of each human-derived odorants (from left to right: 6-methyl-5-heptene-2-one, nonanal, (E)-2-nonenal, decanal, indole, and geranylacetone). (E)-2-nonenal and indole were added as internal standards. Upper traces (blue) are EAD responses. Upward deflections are due to mechanical disturbances during the GC-EAD runs. Nonanal was the only EAD-active peak in chicken extracts (n = 3). Despite several trials (n = 5), we did not observe EAD response to 6-methyl-5-heptene-2-one. (Scale bar in both the GC-EAD runs, 0.2 mV.)