红火蚁告警信息素的GC-EAD分析

背景]2-乙基-3,6-二甲基吡嗪是红火蚁告警信息素的主要成分,本研究旨在分离、鉴定红火蚁工蚁浸提液中告警信息素成分,分析红火蚁工蚁对告警信息素合成样品混合物的电生理反应。方法]200 g红火蚁工蚁的正己烷浸提液过硅胶柱,正己烷—丙酮体系洗脱,气相色谱（GC）和气相色谱—质谱联用（GC-MS）分析检测浸提液中含告警信息素的流分,气相色谱—触角电位联用仪（GC-EAD）分析红火蚁工蚁对2-乙基-3,5（6）-二甲基吡嗪混合物的电生理活性。结果]红火蚁工蚁正己烷浸提液硅胶柱层析分离能够得到含2-乙基-3,6-二甲基吡嗪的流分,GC-MS分析的保留时间在11.45 min。经过GC-EAD分析,发现红火蚁工蚁对2-乙基-3,5（6）-二甲基吡嗪混合物有显著的电生理反应。结论与意义]红火蚁工蚁对2-乙基-3,6-二甲基吡嗪的电生理反应比2-乙基-3,5-二甲基吡嗪高。

Analysis of the alarm pheromone components of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae)

Background ] 2-Ethyl-3,6-dimethylpyrazine is a main alarm pheromone component of the red imported fire ant, Solenop- sis invicta Buren. This study aimed to isolate and identify the reported alarm pheromone component of fire ant workers and to analyze the electrophysiologieal response of fire ant workers to the alarm pheromone component mixture. Method ] Hexane extract of 200 g of fire ant workers was subjected to a silica gel column chromatography and eluted with hexane-acetone solvent system. The alarm pheromone fraction was analyzed by gas chromatography （GC） and gas chromatography-mass spectrometry （GC-MS） analy- ses. The electrophysiological response of fire ant worker tsynthetic o synthetic 2-ethyl-3,5 （6）-dimethylpyrazine mixture was analyzed by gas chromatography-electroantennographic detection （GC-EAD）. Result ] A fraction containing 2-ethyl-3,6-dimethylpyrazine was ob- tained through the silica gel column chromatography of hexane extract of ant workers. The retention time of 2-ethyl-3,6-dimeth- ylpyrazine in the alarm pheromone fraction in GC-MS analysis was 11.45 min. GC-EAD analysis demonstrated that fire ant worker showed significant electrophysiological response to 2-ethyl-3,5 （6）-dimethylpyrazine mixture. Conclusion and significance] Fire ant workers showed higher activity to 2-ethyl-3,6-dimethylpyrazine than to 2-ethy-3,5-dimethylpyrazine, which can be used in baits to attract workers.