東方果實蠅雄蟲萃取物之誘雌成分鑑定與生物檢測

Abstract

東方果實蠅 (Bactrocera dorsalis (Hendel) ) 是台灣重要的果樹害蟲，對於危害的雌蟲，沒有有效的防治策略，所以研究雌蟲誘引物質顯得相當重要，本研究將分析與鑑定東方果實蠅雄蟲釋放的性費洛蒙。觀察雄蟲的求偶行為，僅在黃昏時產生振翅行為，幫助費洛蒙擴散，以誘引雌蟲。在Y型飛行通道中試驗活雄蟲氣味對雌蟲的誘引效力，有32 ± 1%的雌蟲可被誘引，且與對照組 (1%) 有顯著差異。使用全身萃取法萃取雄蟲釋放之氣味，以氣相層析質譜儀 (GC-MS) 分析，methyl eugenol-fed (ME-fed) 雄蟲萃取液有37種化合物，其中16種為已知化合物。已知化合物中有7種與methyl eugenol (ME) 有密切相關，包括4-vinyl-2-methoxy-phenol (4V2MP)、eugenol、isoeugenol、1-methyoxy-2-(1-methyl-2-propenyl) benzene、methyl isoeugenol、2-allyl-4,5- dimethoxyphenol (DMP) 和coniferyl alcohol (CA)，而且這些化合物在non-ME-fed雄蟲萃取液中未被發現。以氣相層析儀-觸角電圖 (GC-EAD) 分析雄蟲萃取液中的活性成分，由結果得知N-(3-methylbutyl) acetamide (NMBA)、4V2MP、Eugenol、ME及DMP能使雌蟲產生電生理反應。除了DMP以外，其餘的活性化合物皆已獲得，且進行雌蟲的誘引效力試驗。在小帳棚內以透明塑膠陷阱進行雌蟲誘引試驗結果中，ME (雌蟲誘引率為45.52 ± 5.21%) 和混合物 (雌蟲誘引率為53.68 ± 6.29%) 的誘引效力較佳，與其餘的活性化合物間有顯著差異。在網室內以黏蟲紙進行誘引試驗結果中，ME (雌蟲誘引率為23.17 ± 1.83%) 和混合物 (雌蟲誘引率為32.17 ± 2.24%) 的誘引效果較佳，除了Eugenol與ME間沒有顯著差異外，ME和混合物與其餘活性化合物間有顯著差異。混合物有最高的誘引比率，而次要化合物單品的誘引比率低，可能對主要化合物有協力作用，但是混合物與ME的誘引效果間沒有顯著差異，可能是混合物中缺少DMP的緣故。活性化合物在田間的誘引效力尚待評估。

Oriental fruit fly (OFF), Bactrocera dorsalis (Hendel), is one of most important pests in Taiwan. However, the female attractant, such as sex pheromone, used for controlling OFF has not been available. In this study, male-released sex pheromone was identified and analyzed. Male performs wing vibration for dispersing sex pheromone at dusk. Y tunnel experiment confirms the behavior that male attracts female by odor cue. The result shows male-released odor attracted 32 ± 1% females, and it differs significantly from control. Basing on this phenomenon, blends were extracted from male flies by whole-body extraction method. The extractions were analyzed by gas chromatography-mass spectrometry (GC-MS). The methyl eugenol-fed (ME-fed) male extraction contains 37 compounds. And 7 compounds, including 4-vinyl-2-methoxy- phenol (4V2MP), eugenol, isoeugenol, 1-methyoxy-2-(1-methyl-2-propenyl) benzene, methyl isoeugenol, 2-allyl-4,5-dimethoxyphenol (DMP), and coniferyl alcohol (CA) are ME-derived among those identifiable compounds. Further analysis by gas chromatography-electroantennographic detection (GC-EAD) is adopted for screening out the active compounds. Five active compounds, including N-(3-methylbutyl) acetamide (NMBA), 4V2MP, Eugenol, ME, and DMP, have been identified, and were further tested by behavioral experiment to determine the attractiveness to the females excluding DMP. In the insect rearing tent, ME (45.52 ± 5.21%) and blend (53.68 ± 6.29%) attracted significantly more females than other active compounds. In the greenhouse, ME (23.17 ± 1.83%) and blend (32.17 ± 2.24%) attracted significantly more females than 4V2MP and NMBA. The blend attracted more female flies than the minor compounds. The minor compounds might be synergistic to major compounds, however further study is needed to clarify the effectiveness of the five active compounds.