茶梢和茶花主要挥发物对门氏食蚜蝇和大草蛉引诱效应

用Y形嗅觉仪进行的生测表明茶二叉蚜和蚜害茶梢复合体挥发物显著引诱门氏食蚜蝇和大草蛉．剂量为10^-4g·ml^-1时，在味源和空气对照之间，食蚜蝇对源于复合体的香叶醇和水杨酸甲酯、源于完整茶梢的正辛醇、源于茶花的橙花醇有极显著趋性(P<0．01)，对源于复合体的反-2-己烯-1-醇、反-2-己烯醛、罗勒烯和芳樟醇有显著趋性(P<0．05)；大草蛉则显著趋向源于完整茶梢的正辛醇和己醛(P<0．05)．剂量为10^-2g·ml^-1时，食蚜蝇对己醛、橙花醇及源于复合体的苯甲醛有显著趋性，大草蛉显著趋向于苯甲醛、己醛、香叶醇和反-2-己烯-1-醇．结果表明，除了醛类和水杨酸甲酯外，香叶醇、正辛醇和反-2-己烯-1-醇等也有显著引诱效应。2种天敌对信息物的反应是有阈值的，两种剂量的己醛均显著引诱大草蛉，橙花醇是引导食蚜蝇朝茶花定向的信息物。

Attraction effect of main volatile components from tea shoots and flowers on Sphaerophoria menthastri ( Diptera:Syrphidae) and Chrysopa septempunctata ( Neuroptera:Chrysopidae)

The Y-olfactometer bioassays showed that the volatiles from tea aphids and tea aphid-damaged tea shoots (PHC) strongly attracted Sphaerophoria menthastri and Chrysopa septempunctata. At the dosage of 10(-4) g x ml(-1), S. menthastri selected geraniol and methyl salicylate from PHC, n-octanol from intact tea shoots (ITS), nerol from tea flowers (P < 0.01), and (E)-2-hexen-1-ol, E-2-hexenal, 1,3,6-octatriene-3,7-dimethyl and linalool from PHC (P < 0.05), while C. septempunctata selected n-octanol and hexanal from ITS (P < 0.05). At the dosage of 10(-2) g x ml(-1), S. menthastri selected hexanal, nerol and benzaldehyde from PHC (P < 0.05), while C. septempunctata selected hexanal, benzaldehyde, geraniol and (E)-2-hexen-1-ol (P < 0.05). The experimental results showed that besides aldehydes and methyl salicylate, geraniol, n-octanol and (E)-2-hexen-1-ol were significantly attractive to the natural enemies. The selective responses of natural enemies were restricted by thresholds. Both dosages of hexanal significantly attracted C. septempunctata. Nerol might be an infochemicals seducing S. menthastri to orient to tea flowers.