USDA ARS Stored-Product Insects Research Unit Department of Entomology, 237 Russell Laboratories, University of Wisconsin, 53706, Madison, Wisconsin.
J Chem Ecol. 1996 Dec;22(12):2233-49. doi: 10.1007/BF02029543.
Female cowpea weevils,Callosobruchus maculatus, produce a sex pheromone that elicits orientation and sexual behavior in males. Bioassay-directed isolation of the sex pheromone was conducted and compounds in the active fraction were identified and synthesized. Volatiles were collected from individual virgin females by adsorption on filter paper dises and hexane extraction. A bioassay was used in which the locomotory response of single males in glass vials was recorded upon exposure to treatments or controls. Crude extracts were subjected to silica gel column chromatography with solvents of increasing polarity; all activity eluted with methanol. Activity in the highly polar methanol fraction suggested a carboxylic acid or a compound with multiple polar functionality. Acid-base partitioning of the crude extract isolated all activity in the acid fraction, confirming that the pheromone was a carboxylic acid. The acid fraction was further fractionated by preparative GC with a Carbowax column. The most active GC fraction contained the following five 8-carbon acids identified by GC-MS and comparison with synthetic candidates: 3-methyleneheptanoic acid, (Z)-3-methyl-3-heptenoic acid, (E)-3-methyl-3-heptenoic acid, (Z)-3-methyl-2-heptenoic acid, and (E)-3-methyl-2-heptenoic acid. Each of the synthetic acids was active individually for males, and combinations of two or more of the acid pheromones had an additive effect. Upwind flight responses to natural and synthetic pheromones were observed in a flight tunnel. (Z)-3-Methyl-2-heptenoic acid was previously identified as the sex pheromone for the relatedC. analis, but this and the other four acid pheromones fromC. maculatus were inactive for maleC. analis. There was no cross-attraction betweenC. maculatus andC. analis in reciprocal studies using extracted volatiles from females of both species, GC-MS analysis ofC. analis female volatiles failed to detect any of theC. maculatus compounds but did find an unidentified C-8 acid with a GC retention time different from any of theC. maculatus pheromones.
雌性豇豆象，Callosobruchus maculatus，会产生一种性信息素，这种信息素可以引起雄性的定向和性行为。通过生物测定指导分离性信息素，并鉴定和合成活性部分的化合物。将来自单个处女雌性的挥发物通过吸附在滤纸盘上和己烷萃取收集。使用生物测定法，在玻璃小瓶中记录单个雄性的运动反应，以暴露于处理或对照。粗提取物用硅胶柱层析法用极性增加的溶剂处理;所有活性均用甲醇洗脱。高极性甲醇部分的活性表明是羧酸或具有多个极性官能团的化合物。粗提取物的酸碱分配将所有活性分离到酸部分，确认信息素是羧酸。酸部分通过用 Carbowax 柱进行制备 GC 进一步分级。最活跃的 GC 馏分包含以下五种通过 GC-MS 鉴定的 8 碳酸和与合成候选物的比较：3-亚甲基庚酸、（Z）-3-甲基-3-庚烯酸、（E）-3-甲基-3-庚烯酸、（Z）-3-甲基-2-庚烯酸和（E）-3-甲基-2-庚烯酸。每种合成酸对雄性都是单独有效的，两种或更多种酸信息素的组合具有相加效应。在飞行隧道中观察到对天然和合成信息素的顺风飞行反应。（Z）-3-甲基-2-庚烯酸以前被鉴定为相关 C. analis 的性信息素，但这种和来自 C. maculatus 的其他四种酸信息素对雄性 C. analis 都没有活性。在使用来自两个物种的雌性提取挥发物的相互研究中，C. maculatus 和 C. analis 之间没有交叉吸引力，GC-MS 分析 C. analis 雌性挥发物未检测到任何 C. maculatus 化合物，但确实发现了一种具有与任何 C. maculatus 信息素不同的 GC 保留时间的未鉴定的 C-8 酸。
