Semi-field evaluation of several novel alkenol analogs of 1-octen-3-ol as attractants to adult Aedes albopictus and Culex quinquefasciatus.

The compound 1-octen-3-ol is a known attractant of some mosquito species, which has led to the hypothesis that olfactory stimulation by this alkenol may be associated with the following structural elements: a terminal site of unsaturation or high electron density; a structural capability for hydrogen bonding, e.g., -OH, -NH2, NHR, NR2, etc.; a saturated hydrocarbon chain of a certain minimum length; and a certain relative distance between the region of high electron density and the alcohol (or other hydrogen-bonding) functional group. Using this logic, we synthesized 20 alkenol analogs based on the octenol double-bonded carbon skeleton. The attraction of female Aedes albopictus and Culex quinquefasciatus to these analogs was compared with 1-octen-3-ol as a standard in semi-field trials. For both species, collections from Mosquito Magnet-X (MMX) suction traps baited with the alkenol analogs in the absence of carbon dioxide were not significantly different from octenol-only baited traps, with the exception of (Z)-3-hepten-1-ol which collected significantly more Ae. albopictus. In the presence of CO2, most of the collections from traps baited with an alkenol were considerably increased for both species but not different from octenol plus CO2, with the exception of Ae. albopictus where (Z)-3-decen-1-ol, (Z)-4-hexen-1-ol, 7-octen-2-ol, and 8-nonen-3-ol significantly depressed trap catches. Although no clearly identifiable structure-activity relationship could be determined from our collected data, we did find that MMX traps baited with carbon dioxide and 4-penten-2-ol or (E)-2-decen-4-ol significantly enhanced Cx. quinquefasciatus collections up to nearly 3-fold compared with octenol plus carbon dioxide.