Antennal responses of tsetse to analogues of the attractant 1‐octen‐3‐ol

Abstract

Abstract. Antennal movement responses of male Glossina morsitans morsitans Westwood to twelve analogues of the tsetse olfactory attractant 1‐octen‐3‐ol were investigated to determine their structure‐activity relationships. The results indicate that the chemoreceptors which perceive this set of kairomones may not be highly specific. Activity is dependent on the length of the alkyl chain; also homologues with odd alkyl chains such as 3‐buten‐2‐ol, 1‐hexen‐3‐ol and 1‐octen‐3‐ol evoked higher antennal responses than homologues with even alkyl chains such as l‐nonen‐3‐ol, 1‐hepten‐3‐ol and 1‐penten‐3‐ol. Comparison of the activities of eight carbon structural variants of 1‐octen‐3‐ol showed that the structural requirements for activity of the functional end of the molecule may not be rigid; thus, 1‐octyn‐3‐ol elicited relatively high responses. However, low responses to 1‐octene and 3‐octanol showed that both the π electron system as well as the oxygen function are important for activity. Laboratory bioassay findings indicate that compounds such as 1‐octyn‐3‐ol, 3‐buten‐2‐ol, allyl alcohol and 1‐octen‐3‐one which evoke antennal responses 2–3 times greater than the control have attractive properties and preliminary field investigations show that 3‐buten‐2‐ol and allyl alcohol significantly increase trap catches.