Liu Ya-Jia, Hall David, Cross Jerry, Farman Dudley, Amarawardana Lakmali, Liu Qing-Ran, He Xiong-Kui
Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, 100094, China.
J Chem Ecol. 2009 Jun;35(6):715-23. doi: 10.1007/s10886-009-9647-z. Epub 2009 Jun 25.
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.
菊花瘿蚊（Rhopalomyia longicauda，双翅目：瘿蚊科）是中国商业化种植的菊花（Dendranthema morifolium (Ramat.) Tzvel.）最重要的害虫，其性信息素已被鉴定、合成并进行了田间试验。在中国，用Porapak收集了未交配雌虫和雄虫的挥发性化学物质，并送往英国进行分析。对雌虫挥发性物质收集物进行的气相色谱 - 触角电位检测（GC - EAG）分析显示，有两种化合物能引起雄虫触角的反应，而这些化合物在雄虫收集物中不存在。通过气相色谱（GC）保留指数、电子轰击和化学电离模式下的质谱、氢化、环氧化以及与二甲基二硫的衍生化反应，将主要的EAG活性化合物鉴定为2 - 丁氧基 - 8 - 十七碳烯。次要的EAG活性化合物被鉴定为相应的醇。收集物中丁酸酯与醇的比例为1:0.26。由（Z） - 7 - 十六碳烯基乙酸酯合成了外消旋（Z） - 8 - 十七碳烯 - 2 - 醇及其相应的丁酸酯，发现合成化合物的GC保留指数和质谱与天然的、雌性特异性成分相同。在对映选择性环糊精气相色谱柱上对挥发性收集物进行分析表明，天然性信息素含有（2S,8Z） - 2 - 丁氧基 - 8 - 十七碳烯。田间试验表明，含有外消旋（Z） - 2 - 丁氧基 - 8 - 十七碳烯的橡胶隔片对菊花瘿蚊雄虫具有吸引力。（天然存在的）S - 对映体与外消旋体的吸引力相同，而R - 对映体对雄虫没有吸引力，并且不抑制S - 对映体 的活性。即使存在少量相应的醇，丁酸酯的吸引力也会显著降低。
