杨圆蚧利它信息素和小蜂阻止产卵信息素对小蜂控制力的影响

寄主对寄生性天敌具有引诱作用和寄生小蜂分泌产卵信息素．是保证小蜂对寄主有较高的控制力的必要条件，研究发现杨圆蚧中存在着有利于长棒四节蚜小蜂和黄胸扑虱蚜小蜂寻找寄主和产卵的一类化学物质——利它信息素．主要存在于杨田蚧的介壳中．是一类具有水溶性特征的化台物．可帮助长棒四节蚜小蜂和黄胸扑虱蚜小蜂进行寄主的定位和辨识。因此可以保证在寄主低密度条件下．成功地进行寄主定位．对寄主进行有效的控制。长棒四节蚜小蜂和黄胸扑虱蚜小蜂在寄主杨圆蚧一龄固定若虫体上产卵后．留下可以阻止同种的其它个体或异种的个体进行寄主检查和产卵的物质．即产卵标速信息素。这样便极大地减少了杨田蚧之间复寄生现采的发生．确保了杨圆蚧若虫体内的小蜂有充足的营养．也使小蜂利用有限的卵．控制尽可能多的寄主．使杨圃蚧和小蜂保持在一定的种群水平。

The Influence of Kairomone in Quadraspidiotus gigas and Oviposition Deterring Pheromone in Parasitoids on the Control Ability of Those Parasitoids

airomone that mainly existed in the scale of Quadraspidiotus gigas are some water solvable compounds. The exist of those kairomone helps Pteroptrix longiclava and Encarasis gigas search and determine their host for oviposition so as to control the host population in a low level. The experimental results indicated that after oviposition of Pteroptrix longiclava and Encarasis gigas on their hosts some chemical compounds that have oviposition deterring effect were left on those parasited hosts. Those compounds have some deterring effects on host searching and determining activities of the two parasitods. The exist of those compounds can significantly reduce the occurrence of superparasitism or multiparasitism, assure that the chalicids in the bodies of Q. gigas have sufficient nutrition, and let those chalcids use the limited eggs to control host as much as possible.