【作者】 王伟；

【导师】 程立生； 刘万学；

【作者基本信息】 海南大学 ， 作物害虫学， 2012， 博士

【摘要】 卵育型(synovigenic)寄生蜂指雌蜂在羽化时卵巢中无成熟卵子或成熟卵子很少,雌蜂需要取食寄主获取满足其卵成熟及持续产卵和存活的营养需求。寄生蜂卵育型程度常以卵子发生指数(Ovigey Index,OI)来表示,即雌蜂羽化时体内所含的成熟卵数量占雌蜂一生潜在生殖力的比例。鉴于卵育型雌蜂以寄主为食的资源利用方式和寄主取食行为(host-feeding)在生态学上的进化意义以及对生物防治应用的启示,本研究以斑潜蝇类害虫的两种优势寄生蜂潜蝇姬小蜂和芙新姬小蜂为对象,采用实验生态学、昆虫生理学、昆虫行为学等相结合方法,首先研究了两种雌蜂内生殖系统结构及卵巢发育和卵子发生动态；接下来,从单种角度,分别研究2种雌蜂取食寄主(斑潜蝇幼虫)对其寿命和卵子发生/繁殖力等生活史特征随优势效应；雌蜂取食寄主的营养物质吸收和发生动态；然后,进一步研究了自然界中常见五种糖对2种雌蜂寿命和繁殖力等生活史的影响及其对雌蜂体内营养物质的影响动态；最后研究了2种雌蜂耐营养协迫能力。在此基础上,同时对两种寄生蜂生活史特征比较,建立寄生蜂卵育型程度与其生活史特征差异的关系。主要研究结果如下：1、两种雌蜂内生殖系统结构、卵巢发育和卵子发生动态采用解剖的方法观察了两种雌蜂内生殖系统结构和雌蜂的卵巢发育模式及卵子发生动态,结果显示,1)潜蝇姬小蜂雌蜂和芙新姬小蜂雌蜂的内生殖系统主要由1对卵巢、2条侧输卵管、1条中输卵管、1个受精囊、1个粘液腺、1个毒腺和1条杜氏腺组成；此外,潜蝇姬小蜂还有1对中输卵管附腺。两种雌蜂的卵巢基本由6根卵巢管组成,个体间偶有差别。2)两种雌蜂的卵巢均在化蛹第1d形成；化蛹第3天,芙新姬小蜂形成卵巢管和卵室并出现卵黄沉淀,均比潜蝇姬小蜂早1d；潜蝇姬小蜂初羽化时无成熟卵子,为强卵育型寄生蜂；而芙新姬小蜂羽化时有部分成熟卵子,卵育型程度稍弱；与取食清水(对照)相比,取食寄主能够促进卵子的快速形成。2、两种雌蜂取食寄主食物相对于非寄主食物对其寿命和卵子发生的优势分别比较了两种雌蜂取食寄主食物(美洲斑潜蝇幼虫)、葡萄糖、寄主+葡萄糖、蒸馏水的寿命和卵子发生动态,结果显示,1)潜蝇姬小蜂取食寄主幼虫、葡萄糖、寄主+葡萄糖以及蒸馏水的寿命分别为20.2±1.6d、34.6±1.9d、23.9±2.1d和3.3±0.2d,羽化后10d内成熟卵子累积量分别为139.2±1.5粒、36.8±0.4粒、134.9±1.6粒和5.2±0.3粒；雌蜂卵子重吸收后,重新取食寄主幼虫可以在24h形成新的成熟卵子,而取食葡萄糖不能形成新的卵子；2)芙新姬小蜂取食寄主幼虫、葡萄糖、寄主+葡萄糖以及蒸馏水的寿命分别为11.4±0.7d、24.2±1.6d、16.1±1.4d和2.7±0.2d,羽化后10d内成熟卵子累积量分别为99.6±1.1粒、64.4±0.8粒、102.2±1.0粒和28.7±1.0；雌蜂卵子重吸收后,取食寄主可以在12h形成新的成熟卵子,取食葡萄糖不能形成新的卵子；3)寄主取食和非寄主食物均能显著延长2种雌蜂的寿命,寄主取食促进形成更多成熟卵子,而非寄主食物不能促进卵子的形成,但能延缓卵子的重吸收；在提供寄主的情况下,补充营养葡萄糖对两种雌蜂的寿命和卵子发生促进作用存在差异,总体表现均可以延长寿命,但对总卵子数没有显著影响。3、两种雌蜂取食寄主相对于非寄主食物对其自身体内营养物质含量的影响分别比较测定2种雌蜂取食寄主幼虫、葡萄糖、寄主+葡萄糖、蒸馏水的体内营养指标的发生动态,结果显示,1)取食寄主的潜蝇姬小蜂体内的体糖和肝糖含量明显低于取食非寄主食物的雌蜂,脂类物质的含量高于取食非寄主食物的雌蜂；2)取食寄主的芙新姬小蜂体内果糖和肝糖的含量明显低于取食寄主的雌蜂,脂在物质高于取食非寄主的雌蜂；3)潜蝇姬小蜂脂类物质下降趋势不明显,而芙新姬小蜂体内的脂类物质呈快速下降趋势,说明潜蝇姬小蜂具有一定合能脂类物质的能力,而芙新姬小蜂则不能合成脂类物质。4、自然界常见5种糖对于两种雌蜂寿命和卵子发生的影响分别比较测定了2种雌蜂取食自然界中常见的五种糖(葡萄糖、果糖、蔗糖、海藻糖、松三糖)的寿命和卵子发生动态,结果显示,1)取食果糖的潜蝇姬小蜂寿命最长,40.3±1.6d,取食松三糖的寿命最短,为24.5±1.8d；2)对于芙新姬小蜂而言,取食葡萄糖的个体寿命最长,取食松三糖的雌蜂寿命最短；3)单糖在潜蝇姬小蜂和芙新姬小蜂的寿命中均起着最重要作用,但对雌蜂的最佳适应则存在种间差异。5、两种雌蜂的耐营养胁迫能力比较测定了2种雌蜂在不同的营养胁迫处理下,雌蜂的寿命及资本营养(capital)和摄取(income)营养的含量动态,结果显示,1)寄生蜂羽化初期个体的大小与初始资本营养成正相关,初羽化的潜蝇姬小蜂和芙新姬小蜂体内以体糖和肝糖含量最高；2)短期的营养胁迫对潜蝇姬小蜂和芙新姬小蜂寿命影响不大,随着营养胁迫时间的加深,两种寄生蜂的寿命急剧缩短；3)发生营养协迫时,通过补充营养后,雌蜂体内糖类物质保持在一定的水平,说明这两种蜂能合成糖类物质,但脂类物质含量逐渐减少,由于潜蝇姬小蜂下降程度远低于芙新姬小蜂,进一步证明潜蝇姬小蜂具有一定合能脂类物质的能力,而芙新姬小蜂不能合成脂类物质。综合分析,潜蝇姬小蜂和芙新姬小蜂均为典型的卵育型寄生蜂,但潜蝇姬小蜂的卵育型程度更强；两种雌蜂取食寄主幼虫和非寄主食物均能延长其寿命,但寄主食物能促进形成新的成熟卵子,而非寄主食物不能促进形成新的成熟卵子,但可以延缓卵子的重吸收,这是因为这2种雌蜂成虫期均不具备脂肪生成能力,因此,雌蜂的卵子形成依赖于寄主食物中的脂肪营养,而寿命则依赖于获得的碳水化合物。研究结果／结论将最终在理论上进一步丰富寄主取食行为在寄生蜂行为生态学上的进化意义,并在实践上为该类寄生蜂生物防治应用提供指导。更多还原

【Abstract】 Synovigenic parasitoid refers to parasitoids with no or only few mature eggs in the ovaries of newly emerged females, thus female parasitoids have to feed on host food and/or non-host food to provide nutrient necessary for egg maturation and oviposition. Ovigey index (OI) is often used for estimating synovigenic degree of the parasitoids, i.e. the ratio of mature eggs in a newly emerged female to total eggs in its lifespan. In view that the resource utilization of female wasps of synovigenic parasitoids with hosts as food and that the host-feeding behavior have important significances in evolutionary ecology and in biological control, this project conducts studies on the important parasitoids of Liriomyza leafminers, i.e., Diglyphus isaea and Neochrysocharis formosa using the methods of experimental ecology, insect physiology, insect behavior etc. Firstly, the effect of female wasps of the two species feeding on host larvae on life history traits such as longevity and fecundity is studied, respectively. Then, the dynamics of nutrient absorption and metabolism after the female wasps of the single species feed on hosts is studied in order to clarify the nutritional and physiological mechanisms of host-feeding; meanwhile the correlation between the feeding and oviposition behaviors of female wasps and the inherent nutrient level wan analyzed to ascertain the ability of female wasps dealing with the variable resources. On this basis, the life history traits of the two species are compared, and the relationship between the synovigenic differentiation (Ovigey Index, OI) with the difference in life history traits, resource allocation strategies and nutrient utilization efficiency is established. The main results were listed as following:1. Structure of internal reproductive systems, ovarian development and oogenesis dynamics of the two parasitoidsThe structure of internal reproductive systems and developmental pattern of ovary in the two parasitoids were dissected and observed. The results showed that1) the internal reproductive systems of Diglyphus isaea Walker and Neochrysocharis formosa (Westwood) mainly contained a pair of ovary, two lateral oviducts, a common oviduct, a spermatheca, a mucous gland, a venom gland and a alkaline gland. In addition, there was a pair of accessory gland of median oviduct in female D. isaea. In general, the ovaries of both the two parasitoids were composed of6ovarian tubes, but difference was observed between individuals occasionally.2) The ovaries of both the two parasitoids were produced at the1st day after pupation. Ovarian tubes and egg-chamber were produced and vitellus began to be deposited in N. formosa at the3rd days after pupation, which were one day earlier than in D. isaea. No mature eggs were observed in newly emerged D. isaea females, thus it belongs to a high synovigenic parasitoid. However, some eggs has matured in newly emerged N. formosa females, so its synovigenic intension is weaker compared with D. isaea. Egg development could be accelerated when newly emerged female parasitoid fed on its hosts compared with clear water (control).2. Advantage of longevity and oogenesis of the two parasitoids feeding with host foods compared with feeding with non-host foodsThe longevity and oogenesis dynamics of the two parasitoids fed with hosts(Liriomyza sativae larvae), glucose, hosts plus glucose, distilled water were observed. The results showed that The results showed that1) The longevities of N. formosa females fed with hosts, glucose, hosts plus glucose, distilled water were20.2±1.6,34.6±1.9,23.9±2.1and3.3±0.2days, and the cumulant of mature eggs were139.2±1.5,36.8±0.4,134.9±1.6and5.2±0.3eggs/female within10days after emergence, respectively. After reabsorption of eggs, new mature eggs were produced at24hours after females re-fed on host larvae, but no new mature eggs were observed when the parasitoid fed on glucose.2) The longevities of N. formosa females fed with hosts, glucose, hosts plus glucose, distilled water were11.4±0.7,24.2±1.6,16.1±1.4and2.7±0.2days, and the cumulant of mature eggs were99.6±1.1,64.4±0.8,102.2±1.0and28.7±1.0eggs/female within10days after emergence, respectively. After reabsorption of eggs, new mature eggs were produced at12hours after females re-fed on host larvae, but no new mature eggs were observed when the parasitoid fed on glucose.3) Hosts and non-host foods can prolong significantly the longevities of the two parasitoids, and hosts can promote and enhance the number of more eggs. Although non-host foods can not promote oogenesis of the two parasitoids, glucose can postpone reabsorption of eggs. Differences in the longevity and oogenesis were observed between the two parasitoids, and the longevities of both the two parasitoids were extended, but total number of eggs in the two parasitoids was affected, when glucose were provided under the existence of host larvae. 3Effects of host feeding and non-host foods on contents of nutrient substances in the female adults of the two parasitoidsThe dynamics of nutrient indices in the female adults of the two parasitoids fed with host larvae, glucose, hosts plus glucose, distilled water were determined and compared. The results indicated that1) the glucosinolates and glycogen contents in the female adults of D. isaea fed with host larvae were significantly lower than those fed with non-host foods, but lipid contents fed with host larvae were higher than those fed with non-host foods.2) The fructose and glycogen contents in the female adults of N. formosa fed with host larvae were significantly lower than those fed with non-host foods, but lipid contents fed with host larvae were also higher than those fed with non-host foods.3) The lipid contents in D. isaea and N. formosa revealed a degressive trend, this demonstrates that the two parasitoids can’t synthesize the substance.4. Effects of five common sugars on longevity and oogenesis of female adults of the two parasitoidsThe longevity and oogenesis dynamics of female adults of the two parasitoids fed with five common sugars in nature (glucose, fructose, sucrose, fucose and melezitos) were determined and compared. The results showed that1) the longevity of female D. isaea fed with monosaccharide was the longest, with the value of40.3±1.6days, and that fed with melezitos was the shortest, which was24.5±1.8days.2) For N. formosa female, the longest longevity was observed in the treatment of glucose, and the shortest was also noticed in the treatment of melezitos.3) Monosaccharide plays an important role in the longevities of both D. isaea and N. formosa, but there was a difference in the optimal adaption of monosaccharide to the parasitoids between the two parasitoids.5. Tolerance abilities of female adults of the two parasitoids to nutrient stressesThe longevity, capital and nutrition income dynamics of female adults of the two parasitoids were determined and compared under different nutrient stresses. The results revealed that1) there was a positive correlation between the body sizes of newly emerged adult parasitoids and their original capital nutrition, and the contents of glucosinolates and glycogen were the highest in the newly emerged D. isaea and N. formosa adults.2) The short-term nutrient stress did not affect significantly the longevities of D. isaea and N. formosa, but with the stress time was extended, the longevities of the two parasitoids were shortened sharply.3) Since the parasitoids could obtain foods to supply their nutrition, saccharides substances maintained a certain level in female adults when the nutrient stress produced. Since lipid was not synthesized in the parasitoids, its change was in accord with the longevity of female parasitoids.Base on the above results, both D. isaea and N. formosa are classic synovigenic parasitoids, and synovigenic degree of D. isaea is higher than that of N. formosa. The longevities of the two parasitoids were prolonged when they fed on host larvae and non-host foods and hosts can promote oogenesis. Although non-host foods can not promote oogenesis of the two parasitoids, glucose can postpone reabsorption of eggs. This is because lipid can’t be synthesized in the two parasitoids, but oogenesis depends on lipid in nutrient substances, and the longevity only relies on carbohydrates in the adult parasitoids. The results/conclusions will enrich the evolutionary significance of host feeding behaviors in behavioral ecology of parasitoid, and provide a direction for the application of the parasitoids in biological control of pests.更多还原