卷蛾分索赤眼蜂对小菜蛾利他素各成分的接触反应

Contact Response of Trichogrammatoidea bactrae to Different Components of Kairomones of Plutella xylostella

在实验室条件下测定了卷蛾分索赤眼蜂Trichogrammatoidea bactrae Nagaraja对小菜蛾Plutella xylostella（L.）利他素各成分的接触反应.结果表明,卷蛾分索赤眼蜂在正二十七烷处理卵卡上的总接触次数最大,为74.17次,在其处理过的卵卡上的寄生总数也最高,为148.5粒,说明正二十七烷对卷蛾分索赤眼蜂的吸引作用最强;卷蛾分索赤眼蜂在正十六烷处理卵卡上的总接触次数最低,为7次,在其处理过的卵卡上的寄生总数也最低,仅为1.17粒,说明正十六烷对卷蛾分索赤眼蜂的吸引作用最弱.卷蛾分索赤眼蜂对利它素各成分的最大寄生率在20%以上的有2,6,10,14-四甲基十五烷、正二十五烷、正二十七烷和正三十六烷,最大寄生率在5%以下的有正十六烷和正二十二烷.综合分析表明,卷蛾分索赤眼蜂在0.2-2×103ng/cm2范围的卵卡上的接触次数和寄生率相对较高.

The contact responses of egg parasitoid Trichogrammatoidea bactrae Nagaraja to the kairomones of its host diamondback moth（DBM）,Plutella xylotella were bioassayed in laboratory.The attractive effect of 13 hydrocarbons,viz.pentadecane,hexadecane,heptadecane,nonadecane,2,6,10,14-tetramethyl pentadecane,heneicosane,docosane,pentacosane,heptacosane,octacosane,triacontane,pentatriacontane,hexatriacontane on T.bactrae were carried out.The results showed that the total exposure frequency of T.bactrae to the eggs cards treated with heptacosane was 74.71,the highest of all,and the highest parasitism of 53.83% was observed in the eggs cards treated with 2 000 ng/cm2 of heptacosane,which indicated the eggs cards treated with heptacosane was the most attractive to T.bactrae.In contrast,the eggs cards treated with hexadecane showed the weakest attractive to T.bactrae,and the total exposure frequency of T.bactrae against them was only 7,the least of all,and the lowest parasitism as 0.67% of T.bactrae was also observed in the eggs cards treated with the hexadecane.The parasitism of T.bactrae over 20% was found in the eggs cards treated with 2,6,10,14-tetramethyl pentadecane,pentacosane,heptacosane and hexatriacontane,and the parasitism under 5% was found in the eggs cards treated with hexadecane and docosane.In conclusion,the parasitoid T.bactrae showed the higher exposure frequency and parasitism in the eggs cards treated with hydrocarbons concentration between the concentrations 0.2 and 2×103 ng/cm2.