【作者】 吕慧平；

【导师】 胡萃；

【作者基本信息】 浙江大学 ， 农业昆虫与害虫防治， 2002， 博士

【摘要】 蝶蛹金小蜂Pteromalus puparum是重要蔬菜害虫菜粉蝶Pieris rapae的蛹期优势内寄生蜂。该蜂分布广泛，对菜粉蝶的自然控制作用明显。人们已对其生物学、生态学、人工饲料饲养及菜园人工释放等方面开展了许多研究，但对其生殖生理的研究极少，认识尚不深入。本文研究了食料、激素、温度和杀虫剂等因子对蝶蛹金小蜂卵巢发育和卵黄发生的影响，旨在为发挥该蜂的生殖潜能、提高人工繁蜂效率及田间有效保护利用等提供理论指导。研究结果如下： 1 卵巢发育和卵黄发生 当既不喂食、也不提供寄主蛹时，蝶蛹金小蜂雌蜂卵巢管从蛹初期到羽化后48h不断增长，其后的72h内则逐渐缩短。在蛹初期，卵巢中尚未形成卵室；在蛹末期，卵室已形成，但尚无卵黄沉积；在隐成虫期，卵巢中开始形成Ⅰ级卵；成虫刚羽化时开始形成Ⅱ级卵；而成熟卵则在羽化后12h才开始形成。各级卵的数量动态研究表明，Ⅰ级卵以隐成虫期到羽化后18h这段时期内显著较多；Ⅱ级卵在羽化后18h达到峰值，此后急剧下降，至羽化后120h已难以见到；成熟卵在羽化后12至48h之间不断增多，此后逐渐减少。 该蜂卵巢管的数量在不同个体间偶有差异。绝大多数(96.9％)雌蜂的卵巢左右两侧各由3根卵巢管组成。然而发现，分别有2.5、0.4和0.2％的雌蜂其卵巢管数分别为7、5和9根，均以一侧比另一侧多一根。 当供以20％蜂蜜水时，羽化后2、6和10d雌蜂卵巢中成熟卵的数量均与后足胫节的长度呈显著正相关，即雌蜂后足胫节越长，卵巢中成熟卵越多。 不同发育阶段雌蜂的血淋巴和卵巢脂蛋白的PAGE电泳分析表明，该蜂卵黄原蛋白(vitellogenin,Vg)和卵黄磷蛋白(vitellin，Vt)均属于脂蛋白，其Vg的合成起始于隐成虫期。 对卵黄发生前后雌蜂脂肪体的超微结构进行了电镜观察，结果发现：在蛹期，脂肪体细胞内含有大量的蛋白质颗粒和丰富的线粒体，但未观察到粗面内质网，表明此阶段的脂肪体以贮藏功能为主，基本处于无分泌状态，但代谢旺盛。从隐成虫期到羽化后5d的雌成蜂中，脂肪体细胞内粗面内质网、线粒体较为丰富，脂滴较大，说明这一时期的脂肪体细胞均具较强的蛋白合成功能。这些发现支持了上述Vg合成起始于隐成虫期的判断。 对卵巢中滤泡细胞和各级卵母细胞的趔微结构也进行了电镜观察。在卵巢顶端刚形成的卵室中，滤泡细胞与卵母细胞之间产生间隙，两者表面均无微绒毛伸出，卵母细胞中也无卵黄蛋自沉积，但脂滴较多；在1级卵室和！I级卵室中，滤泡细胞和卵毋细胞表面有微绒毛伸出，卵母细胞中沉积有较多的卵黄颗粒和脂滴，而且11级卵室卵母细胞中卵黄颗粒明显大于互级卵室中；在I且级卵室中，卵母细胞内充满卵黄颗粒和脂滴，并己形成卵壳。此外，对位于卵巢管基部已变小的成熟卵观察发现，其中的卵黄颗粒与刚形成的成熟卵相比己犬为减少，而脂滴却明显增多，且卵壳内层出现排列整齐的梳齿状结构。推测该梳齿状结构可能与卵子的重吸收有关。2食料对卯巢发育和卯黄发生的影响 观察了雌蜂取食7种食料即蜂蜜、蔗糖、葡萄糖、果糖、甘露槽、寄主蛹（菜粉蝶蛹）血淋巳和Sf900细胞培养液的水溶液之后卵巢管长度、卵巢中各级卵粒数及Vg和yi含量等的变化。 结果表明，与对照相比（取食然馏水），耿食20％蜂蜜水、20％蔗糖、20％葡萄槽和20％果糖溶液的雌峰存话时间明显较长（ 11d后才有个体开始死亡），处理后相同时问内卵巢管明显较长，卵巢中成熟卵抓著较多，血淋巳和卵巢中的Vg或Vt含量也明显铰高。取食甘露糖的雌蜂，处理后第5大讣始死’亡，卵巢管长度和成熟卵量在处理后第l～2天内接近于取食前卑种食料的雌蜂，但在处理后第3～5大则明显不及前四者。职食菜粉蝶蛹血淋巳和lxSf900细胞培养液的雌蜂，无论是卵巢管长度、成熟卵量，还是血淋巴、卵巢中的Vg或yi含量，与对照均无明显差异。此外还发现，取食蜂蜜水、蔗糖、葡萄糟、果糖和甘露槽溶液后，“成熟卵的长径和短径均显著大于对照；而取食菜粉蝶蛹血淋巴和Sf900细胞培养液后，这两项指标与对照均无显著差异。 上述结果表明，在7种供试食料中，蜂蜜、蔗槽、葡萄槽和果槽溶液不仅可延长雌蜂寿命，且对其卵巢发育和卵黄发生具明显的促进作用；甘露糟虽具一定的促进作用，但其程度显然不如前四者；而菜粉蝶蛹血淋巴和Sf900细胞培养液则均无此促进作用。3激素对卯巢发育和卯黄发主的回响 结果表明，蛹初期用保幼激素（Juvcnne hormone， JH）类似物 metkoptone处理，对雌蜂卵巢发育无明显的抑制或促进作删。采用D。卜【NSA检测处理后雌峰血淋巴和卯皿中Vg或Vt含量，表明该时期删处理对该峰Vt的合成及卵巢对其的摄取均未产生明显 影响。 蛹末期经蜕皮激素（Molting hormone，MH）或高剂量 methopne①．628和 0．314 呶…）处理的雌蜂，与对照相比，其卵巢管明显较短，卵巢中成熟卵显著较少，血淋巴 中 Vg和卵巢中 Vt的含量也较低；而该时期经低剂量 methopreneN．157卜令l）处理的 雌蜂，这些指标均更多还原

【Abstract】 Pteromalus puparum is the dominant endoparasitoid of Pieris rapae pupae, with a wide distribution and high control potential on this insect pest. The parasitoid has been studied throughout the world on its biology, ecology, artificial rearing as well as field releasing. However, reproductive physiology of the parasitoid has been still far from understood, though some aspects in this area had been studied recently in China. In this thesis, effects of several factors including diet, hormone, temperature and insecticide on the ovarian development and vitellogenesis of P. puparum were studied, with aims of providing guidelines for increasing its reproductivity, improving artificial-rearing techniques, and protecting the parasitoid in the field. 1 Ovarian development and vitellogenesisLength of ovariole in P. puparum, which was deprived of diets as well as host pupae at adult stage, increased significantly during the period from early pupal stage to 48 h after emergence, and then decreased gradually within the following 72 h. At early pupal stage, no egg chamber could be observed. At the late pupal stage, egg chambers had occurred, while yolk had not been deposited yet. The grade-I, grade-II and mature eggs began to be generated in the ovary at pharate adult stage, newly-emerged-adult stage and 12 h after emergence, respectively. In terms of egg dynamics, the grade-I egg was maintained at a high level during the period from pharate adult stage to 18 h after emergence. The grade-II egg peaked at 18 h after emergence, then decreased abruptly afterwards, and disappeared at 120 h after emergence. The mature egg, however, increased gradually between 12 and 48 h after emergence.Variance was found to some degree in the number of ovariole in P. puparum. In most of female adults (96.9%), ovary was composed of six ovariole, with three on each side. However, there were 0.4, 2.5 and 0.2% female adults whose ovaries were composed of 5, 7 and 9 ovarioles, respectively, with one ovariole more on one side than the other.Number of mature egg in the ovary was positively correlated with the length of hind tibia in thefemale adults aged 2, 6 and 10 d after emergence and feeding on 20% honey solution. That is, adults with longer hind tibias usually carried more mature eggs in the ovary.Lipoprotein in haemolymph and ovary of female P. puparum was analyzed at various stages using PAGE. The result showed that both vitellogenin (Vg) and vitellin (Vt) in this parasitoid could be classified as lipoprotein. The Synthesis of Vg was initiated at the pharate adult stage.Ultrastructures of fat body cell before and during vitellogenesis of the parasitoid were observed by electro microscope. During pupal stage, large amounts of protein granules and mitochondria were present in fat body cells, but no rough endoplasmic reticulum (RER) could be observed, indicating that fat body during this stage served predominantly as a place of storing proteins, with no secreting but great metabolizing activity. However, during the period from pharate adult stage to 5 d after emergence, large amounts of RER were present in fat body cells besides the mitochondria, and large lipid droplets also occurred. In other words, in this parasitoid, it was at the pharate adult stage that proteins began to be synthesized in large quantities. These findings supported the above result that the synthesis of Vg was probably initiated at pharate adult stage.Ultrastructures of follicle cell and oocyte in the ovary were also observed by electro microscope. In the newly formed egg chambers located at the top of ovary, space were present between follicle cells and oocytes, and there was no microvillus at the surface of either type of cell; in the oocytes, no Vt was deposited, while lots of lipid droplet accumulated. In the grade-I and grade II egg chambers, microvilli could be observed at both surface of follicle cell and oocyte, and besides lipid droplets lots of yolk granules accumulated in oocytes. In addition, yolk granules in grade-II chambers were obviously larg更多还原