东方粘虫雄蛾信息素的生成时期与释放行为

Male pheromone releasing behavior in Mythimna separata(Walker)

【目的】东方粘虫Mythimna separata (Walker)雄蛾味刷的表面超微结构、味刷位置变化节律还未被报道,并且雄蛾信息素的生成时期还没有被确定。【方法】本实验利用扫描电子显微镜观察味刷不同区域的表面结构。应用气相色谱-质谱(GC-MS)检测不同时间段的处于两种位置状态的味刷提取液中苯甲醇的含量,并分析交配过后味刷中苯甲醛的含量变化。【结果】东方粘虫雄蛾的前腹两侧各有一只味刷,电镜扫描发现味刷的毛干内部呈现中空网状,毛干近轴端的表面具有平行的纵脊与孔,过渡区的表面纵脊消失并且分布着大小不一的孔,末端表面呈"蜂窝"状。在雄蛾羽化后8 h,6.67%的味刷从腹部第2节节间膜处缩回到第3、第4腹节囊中;羽化后24 h,96.67%的味刷缩回至腹部囊中。雄蛾味刷缩回至囊内2 h后,所有雄蛾均检测到了苯甲醇;味刷在节间膜处时也有部分雄蛾检测到苯甲醇,尤其是在羽化后24h,80%的雄蛾生成了苯甲醇。雄蛾在交配后苯甲醛并没有显著下降。【结论】雄蛾信息素的生成取决于味刷的位置变化,味刷在节间膜处时信息素已经生成,并在完全缩回囊内后大量合成。雄蛾在求偶、交配过程中味刷不会外翻,只是通过挤压腹部使得囊的边缘张开,从而释放信息素。

[Objectives] To describe the surface ultrastructure and rhythmic movement of hair-pencils in male Mythimna separata(Walker) and the period of pheromone release. [Methods] The surface structure of different regions of hair-pencils was observed under a scanning electron microscope. Gas chromatography-mass spectrometry(GC-MS) was used to detect the content of benzyl alcohol in extracts from hair-pencils at two different positions at different times, and changes in benzaldehyde content in hair-pencils after mating were analyzed. [Results] Male moths have a hair-pencil on each side of the anterior abdomen. The interior of the hair stem is hollow and reticulate and the surface of the proximal shaft has longitudinal ridges and punctate holes. There is a transition area in which the longitudinal ridges are gradually replaced by holes of different sizes. The end of the surface was "honeycomb" shaped. 6.67% of hair-pencils began to retract from the second internode of the abdomen into pockets on the 3-4 segments 8 h after males had emerged. 96.67% of hair-pencils retracted within their pockets 24 h after emergence. 80% of males produced benzyl alcohol, which was detected on hair-pencils after these had been retracted into their pockets for 2 h. Benzyl alcohol was also detected at the internode membrane, especially 24 h after male emergence. There was no significant decrease in the benzaldehyde detected on hair-pencils after mating. [Conclusion] The generation of male pheromone depends on changing the position of hair-pencils. Hormone begins to be generated as hair-pencils are retracted from the intersegmental membrane into their pockets, rather than after hair-pencils are fully retracted into their pockets. Eversion of hair-pencils during courtship and mating behavior was not observed, rather males released pheromone by pressing their anterior abdomen to open the edge of their hair-pencil pockets.