Abstract
Six compound were identified as sex pheromone candidates from abdominal tips of the female browntail moth, Euproctis similis (FUESSLY), using coupled gas chromatography-electroantennographic detection, coupled gas chromatography-mass spectrometric analysis, microreaction, and synthesis. These compounds were (Z)-7-octadecenyl 2'-methylbutyrate (53.5%), (Z)-7-octadecenyl isovalerate (32.1%), (Z)-9-octadecenyl 2'-methylbutyrate (4.3%), (Z)-9-octadecenyl isovalerate (4.8%), (Z)-7-octadecenyl isobutyrate (2.7%) and (Z)-7-octadecenyl butyrate (2.7%). The total amount was determined to be ca. 18.7 ng/female. The enantiomeric distribution of (Z)-7-octadecenyl 2'-methylbutyrate and (Z)-9-octadecenyl 2'-methylbutyrate was tentatively estimated to be (S) : (R) = 7.2. In flight-tunnel bioassays, 7 synthetic components, including optical isomers of (Z)-7-octadecenyl 2'-methylbutyrate, attracted males. In field bioassays, males were captured with blends of 4 to 6 components. Four components of these seven components, (Z)-7-octadecenyl isobutyrate and (Z)-7-octadecenyl butyrate, seemed to be essential for sex attractant activity in the male moths in flight-tunnel and field bioassays.
