菜蛾盘绒茧蜂对寄主小菜蛾幼虫营养的调节和利用  

Regulation and utilization of the host (Plutella xylostella) nutrients by the endoparasitoid Cotesia plutellae

作　　者：汪海燕[1] 余虹[1] 万志伟[1] 徐鹏[1] 陈学新[1] 

机构地区：[1]浙江大学昆虫科学研究所,杭州310029

出　　处：《昆虫学报》2006年第4期574-581,共8页Acta Entomologica Sinica

基　　金：国家自然科学基金项目(30370959);教育部"新世纪优秀人才支持计划"(NCET040521)

摘　　要：寄主小菜蛾Plutellaxylostella被内寄生蜂菜蛾盘绒茧蜂Cotesiaplutellae寄生后,其取食、发育及营养代谢在各种寄生因子的作用下伴随幼蜂的发育而发生很大的变化,畸形细胞作为调节因子之一也发挥了重要的作用。本实验通过比较被寄生和未被寄生小菜蛾血淋巴蛋白浓度以及两种血淋巴对菜蛾盘绒茧蜂幼蜂进行体外培养的培养液的蛋白浓度,发现被寄生小菜蛾血淋巴比未被寄生小菜蛾血淋巴的蛋白浓度略低但差异不显著,而未被寄生小菜蛾血淋巴幼蜂培养液的蛋白浓度显著低于被寄生小菜蛾血淋巴幼蜂培养液的蛋白浓度,证明畸形细胞的蛋白质分泌功能。被寄生后期,小菜蛾体重明显大于未被寄生的小菜蛾体重,而脂肪体重量相比正好相反;通过显微染色观察,在小菜蛾念珠状脂肪体表面粘附有畸形细胞,对脂肪体进行分解破坏而使其成颗粒状;蛋白含量和脂滴浓度测定也表明,脂肪体的可溶性蛋白含量和脂滴浓度也迅速降低,同比低于未被寄生小菜蛾。而与此同时,幼蜂正处在快速生长阶段,中肠酯酶的活性逐步上升,幼蜂得以快速消化吸收小菜蛾体内的营养直到完成幼虫发育,整个幼蜂的脂滴浓度也达到了最大值。因此寄生后期,推测在畸形细胞的协助下,幼蜂吸收了寄主小菜蛾体内的营养为自身生长发育所用。Parasitized by the endoparasitoid Cotesia plutellae （Hymenoptera： Braconidae）, the feeding, development and nutrition metabolism of the host Plutella xylostella （Lepidoptera： Plutellidae） were changed dramatically as the immature parasitoid developed inside. These changes were brought about by the impact of various parasitoid-associated factors. Teratocyte as one factor plays an important role. By comparing the changes of proteins in parasitized host and un-parasitized host haemolymphs and the culture mediums of 2nd instar parasitoid larvae using these two kinds of haemolymph in vitro, we found that the protein concentration in the hemolymph of the parasitized host was only slightly （not significantly） lower than that of the un-parasitized host, but that of the culture medium using unparasitized host hemolymph was significantly lower than that of parasitized host, suggesting that the teratocytes have the ability to secret proteins. The body weight of parasitized host was greater than that of un-parasitized host while the reverse was true for the weight of fat body in the late stage of parasitization. Microscopic observation revealed that the moniliform fat body was broken into granules, which was induced by teratocytes attached the fat body tissue; correspondingly, the soluble protein and lipid concentrations of fat body decreased rapidly, much lower compared to those of un-parasitized host. At the same time parasitoid larva grew rapidly, its midgut became mature and absorbed a large amount of the host nutrients, the esterase activity in the midgut of parasitoid larvae increased accordingly and the amount of total lipid in the parasitoid larva increased up to its highest level. In conclusion, in the late stage of parasitization, the parasitoid larva, with the help of teratocytes, utilized up most of the host nutrients for its own development and growth.

关 键 词：菜蛾盘绒茧蜂 小菜蛾 血淋巴 脂肪体 中肠 畸形细胞 蛋白 脂滴 酯酶活性 

分 类 号：Q965[生物学—昆虫学]