(2S,8Z)-2-Butyroxy-8-heptadecene: Major Component of the Sex Pheromone of Chrysanthemum Gall Midge, Rhopalomyia longicauda

• Published in: Journal of chemical ecology 2009-06, Vol.35 (6), p.715-723
• Main Authors: Liu, Ya-Jia, Hall, David, Cross, Jerry, Farman, Dudley, Amarawardana, Lakmali, Liu, Qing-Ran, He, Xiong-Kui
• Format: Article
• Language: English
• Subjects: (2S,8Z)-8-heptadecen-2-ol; Agriculture; Animals; antennae; Biochemistry; Biological and medical sciences; Biological Microscopy; Biomedical and Life Sciences; Butyrates - analysis; Butyrates - chemistry; Cecidomyiidae; chemical composition; Chemical ecology; Chemicals; Chrysanthemum; Chrysanthemum morifolium; Control; Dendranthema morifolium; Diptera; Diptera - physiology; Ecology; electroantennography; Electrophysiology; enantiomers; Entomology; Female; Field tests; Fundamental and applied biological sciences. Psychology; galls; Gas Chromatography-Mass Spectrometry; Insects; Integrated pest control; Ionization; Life Sciences; Male; Mass spectra; midges; pheromone traps; Pheromones; Phytopathology. Animal pests. Plant and forest protection; Protozoa. Invertebrates; Retention; Rhopalomyia; sex attractants; Sex Attractants - chemistry; sex pheromones; Sexual Behavior, Animal; Stereoisomerism; synthesis; trapping; volatile compounds
• ISSN: 0098-0331; 1573-1561
• DOI: 10.1007/s10886-009-9647-z

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.