(2S,8Z)-2-butyroxy-8-heptadecene: major component of the sex pheromone of chrysanthemum gall midge, Rhopalomyia longicauda.
The sex pheromone of the chrysanthemum gall midge, Rhopalomyia longicauda (Diptera: Cecidomyiidae), the most important insect pest in commercial plantations of chrysanthemum, Dendranthema morifolium (Ramat.) Tzvel., in China, was identified, synthesized, and field-tested. Volatile chemicals from virgin females and males were collected on Porapak in China and sent to the United Kingdom for analysis. Coupled gas chromatographic-electroantennographic detection (GC-EAG) analysis of volatile collections from females revealed two compounds that elicited responses from antennae of males. These compounds were not present in collections from males. The major EAG-active compound was identified as 2-butyroxy-8-heptadecene by gas chromatographic (GC) retention indices, mass spectra, in both electron impact and chemical ionization modes, hydrogenation, epoxidation, and derivatization with dimethyldisulfide. The lesser EAG-active compound was identified as the corresponding alcohol. The ratio of butyrate to alcohol in the collections was 1:0.26. Racemic (Z)-8-heptadecen-2-ol and the corresponding butyrate ester were synthesized from (Z)-7-hexadecenyl acetate, and the synthetic compounds found to have identical GC retention indices and mass spectra to those of the natural, female-specific components. Analysis of the volatile collections on an enantioselective cyclodextrin GC column showed the natural pheromone contained (2S,8Z)-2-butyroxy-8-heptadecene. Field tests showed that rubber septa containing racemic (Z)-2-butyroxy-8-heptadecene were attractive to R. longicauda males. The (naturally occurring) S-enantiomer was equally as attractive as the racemate, while the R-enantiomer was not attractive to males, and did not inhibit the activity of the S-enantiomer. The attractiveness of the butyrate was significantly reduced by the presence of even small amounts of the corresponding alcohol.
Liu
Ya-Jia
YJ
Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, 100094, China.
Hall
David
D
Cross
Jerry
J
Farman
Dudley
D
Amarawardana
Lakmali
L
Liu
Qing-Ran
QR
He
Xiong-Kui
XK
D000818:Animals; D002087:Butyrates / Q000032:analysis* / Q000737:chemistry; D004175:Diptera / Q000502:physiology*; D004594:Electrophysiology; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D012724:Sex Attractants / Q000737:chemistry*; D012726:Sexual Behavior, Animal; D013237:Stereoisomerism
C543646:2-butyroxy-8-heptadecene; D002087:Butyrates; D012724:Sex Attractants