2种寄主取食型寄生蜂的"取食vs.产卵"行为权衡及其生理机制研究

In view that the nutrient resource utilization pattern of female wasps of host-feeding parasitoids with hosts tissue and/or hemolymph as food and their strong biological control potential, this project conduct 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, and focusing on the scientific problem "behaviour trade-off and preference shift of "host-feeding vs. oviposition" and its physiology mechanism". Firstly, the extrinsic environment impact factors (i.e., host and food availability, host quality, etc) and intrinsic impact factors (i.e., oogenesis/egg load, nutrient/ starvation status, etc) "host-feeding vs. oviposition" behaviour trade-off of female wasps of the two species is studied, respectively. Then, physiology mechanism of behaviour trade-off is studied, respectively. On one hand, based on nutrient physiology level, the nutrient content dynamics of egg-laying related (i.e., lipid, hormone, sterol, vitellin, etc) and lifetime related (i.e., various sugar) is determinated, respectively. On the other hand, based on molecular level of nutrient absorption and utilization, transcriptional changes associated with lack of lipid synthesis and sugar metabolism is identified in short- and long-term treatment. On this basis, the behaviour decision and life history traits of the two species are compared, and the relationship between behaviour decision with life history traits diversation (i.e., synovigenic differentiation/ovigey index, resource allocation strategies of capital vs. income nutrient and nutrient utilization efficiency) is established. The results and conclusions will eventually enrich the evolutionary significance of host-feeding behaviour in the behaviour ecology of parasitoids, clarify the strategies of life history differentiation through the resource allocation and utilization in pest control when several parasitoids coexist, and provide practical guidance (i.e., storage, release, coexistence control, etc) for pest biological control with host-feeding parasitoids.

鉴于寄主取食型雌蜂以寄主为食的营养利用方式及生防应用潜力，项目以入侵斑潜蝇的寄生蜂－潜蝇姬小蜂和芙新姬小蜂为对象，围绕"雌蜂面临寄主时"取食vs产卵"的行为权衡及其生理机制"这一科学问题，在前期基础上，采用昆虫生理学、行为学、分子生物学等方法，1）首先探明影响雌蜂"取食vs产卵"行为权衡的外在因子（寄主可获得性等）和内在因子（抱卵量等）；2）并进一步从雌蜂产卵物质（如脂类、激素、固醇、卵黄蛋白等）和存活物质（能量物质－糖类）发生的生理水平，以及产卵物质（脂类）和能量物质（糖类）的吸收代谢相关基因转录组变化的分子水平，明确雌蜂的营养物质吸收利用能力，解析行为决策的内在生理机制。3）继续种间比较，解析雌蜂的行为权衡策略和营养分配策略与生活史分化（卵育型程度）的关系。最终在理论上丰富寄主取食型寄生蜂的行为进化理论，增强对雌蜂应对可变资源环境的适应和调控能力的理解，并在实践上为其田间应用提供指导。

潜蝇姬小蜂和芙新姬小蜂为我国蔬菜潜叶蝇的最优势天敌，并且在田间常常同域共存发生。鉴于寄生蜂取食寄主幼虫的控害行为和营养利用方式以及生防应用潜力，项目核心围绕“雌蜂面临寄主时“取食vs.产卵”的行为权衡及其生理机制”这一科学问题，系统比较研究2种寄生蜂的田间发生与分布、生物生态学特性、控害潜力、控害行为及其生理机制等。主要的研究结果/结论及其意义有：1）发现2种寄生蜂均为典型的寄主取食型寄生蜂和寄主杀死型寄生蜂，即雌蜂具有繁殖型产卵寄生行为和非繁殖型寄主取食行为与寄主叮蛰行为的3种对寄主幼虫的控害行为；并阐析了其控害行为特征与图式。2）证实了2种寄生蜂均为强卵育型寄生蜂；明确了雌蜂成虫需要通过寄主取食才能进一步促进其卵子发生和卵子成熟；揭示了寄生蜂的寄主取食行为特性的生理机制是由于寄生蜂成虫缺乏卵子发生所需要的脂类物质原位合成能力，糖类物质不具备转化促进卵子发生和成熟的营养物质利用能力；发现潜蝇姬小蜂对营养物质的积累和利用能力要强于芙新姬小蜂。3）明确了2种寄生蜂在我国田间发生与分布及时空动态；阐明了2种寄生蜂在温度、食物源以及寄主密度等环境因子影响下的控害潜力；发现雌蜂的非繁殖型寄主致死行为显著增强了寄生蜂的控害潜力，寄生蜂的寄主取食能力正向相关性地影响了寄生蜂的控害潜力。4）阐明了食物源、寄主密度和温度等对雌蜂的控害行为权衡的影响，发现雌蜂的非繁殖型寄主致死行为具有显著性地正向相关的寄主密度效应，补充非寄主食物将使雌蜂的"取食vs寄生"的行为权衡向寄生偏移，高温显著增加雌蜂的非繁殖型寄主致死行为尤其是寄主取食能力。5）明确了两种寄生蜂生态适应性和控害潜力的种间差异以及种间竞争共存效应，发现2种寄生蜂的联合释放并不降低其控害潜力，提出了2种寄生蜂的释放应用策略。项目研究结果/结论在理论上丰富寄主取食型寄生蜂的行为进化理论，增强对雌蜂应对可变资源环境的适应和调控能力的理解，并在实践上为其田间应用提供指导。