长尾潜蝇茧蜂寄生后橘小实蝇幼虫体内4种酶活性的变化

测定长尾潜蝇茧蜂（Diachasmimorpha longicaudata）寄生的4日龄橘小实蝇（B. dorsalis）幼虫体内过氧化氢酶（CAT）、过氧化物酶（POD）、超氧化物歧化酶（SOD）、酚氧化物酶（PO）活性。结果表明：幼虫在被寄生后，在其免疫系统的调节下产生大量的活性氧自由基（ROS），致使被寄生的幼虫较未被寄生的3种抗氧化物酶（CAT、POD、SOD）活性明显高，然而被寄生的幼虫PO活性明显低于未被寄生的幼虫。这4种酶协同作用，从而有效减少寄主体内过量的ROS，保证寄生蜂能有效地寄生，提高寄生蜂的存活率。

The Changes of the Activity of Four Enzymes in Larvae of Bactrocera dorsalis (Hendel) Parasitized by Diachasmimorpha longicaudata

Determinate the activity of catalase(CAT), peroxidase(POD), superoxide dismutase(SOD), phenoloxidase(PO)in the 4th instar larvae of B.dorsalis parasitized by Diachasmimorpha longicaudata. The results showed that after the larvae was parasitized, under the regulation of the immune system there was a great of reactive oxygen species(ROS), which increased the activity of CAT, POD, SOD comparing the parasitized-free larvae. However, the activity of PO was decreased distinctly. The synergy of the four enzymes efficiently decreased excessive ROS in host to guarantee the efficient parasitism and increased the survival rate of parasitic wasps.