芙新姬小蜂孤雌产雌品系和两性品系的同域时空共存与分化及其机制

Neochrysocharis formosa (Westwood) (Hymenoptera: Eulophidae) is an importmant bio-control agent for vegetable agromyzid leafminers all over the world. In China, We first discovered the thelytokous strain of N. formosa in Beijing in May, 2015. And then, it was confirmed that there are occurrence of thelytokous strain and arrhenotokous strain (two reproductive modes) of N. formosa and two strains are widely sympatric spatial-temporal coexistence in the field in China. We implement this research project focus on the scientific question, coexistence and differentiation of spatial and temporal niche of two trains and these mechanisms. Basing on early study, 1) the first, coexistent and differentiated patterns of spatial and temporal niche of two trains and relationships between differentiated pattern and environmental ecology factors, such as climate, temperature and habitat are confirmed through systematic field investigation of occurrence of N. formosa at different eco-climatic zones in China. 2) the second, at lab biological ecology level, we compares the differences of adaption and physiological mechanism between thelytoukous and arrhennotokous strains on the environment conditions (temperature and nutrition) and their competition substitution effect to analyze the bio-ecological basis of coexistence and differentiation of spatial and temporal niche of two trains. 3 the third, in the genetics level, we analyses genetic diversity of two strains and classify the origin of thelytokous parasitoids by exploiting multiple molecular markers (mitochondrial gene. nuclear gene and microsatellite) and interspecific hybridization experiments in parallel to demonstrate their distribution in the field. The research results and conclusions make a good supplement to the hypothesis that symbiotic bacterium could promote parasitoids speciation in theory and provide guidance for the field application of N. formosa in practice.

芙新姬小蜂是蔬菜潜叶蝇的最重要天敌，我们发现该蜂在我国存在孤雌产雌品系和两性品系（两种繁殖模式），且在田间同域共同发生。项目围绕“两种品系的时空生态位共存和分化及其机理”这一科学问题，在前期研究工作基础上，1）通过芙新姬小蜂在我国不同气候生态区发生的田间系统调查，明确2种品系的时空生态位共存与分化格局，确定分布格局与气候/温度、生境等环境生态因子的关系；2）从室内生物生态学层面，比较研究2种品系对环境条件（温度和营养等）的适应性及其生理机制差异，以及品系间的竞争替代效应，解析2种品系时空生态位分布格局的生物生态学基础；3）采用线粒体基因、核基因及微卫星标记方法以及品系间杂交实验等相结合的方法，比较2种品系的遗传多样性，确定孤雌品系的起源，从遗传学层面解析2种品系的时空生态位分布格局。研究结果/结论在理论上将丰富内生菌促进寄生蜂物种形成假说，在实践上为芙新姬小蜂的应用实践提供指导。

芙新姬小蜂是我国蔬菜潜叶蝇类害虫的田间优势寄生性天敌，我们发现该寄生蜂蜂在我国同时存在孤雌产雌品系和两性品系，即同时存在孤雌产雌和两性繁殖的两种繁殖模式，且在田间常常同域共同发生。基于前期的工作基础和初步发现，项目核心围绕“芙新姬小蜂两种品系的时空生态位共存和分化及其机理”这一科学问题，研究芙新姬小蜂在我国田间时空发生动态格局与生态位分化，确证品系间的竞争演替效应，阐明品系间和品系内的遗传分化与进化，解析物种形成与分化的遗传学基础以及生态位分化与演替的生物生态学基础等。主要的研究结果/结论/新发现及其意义有：1）在芙新姬小蜂田间调查的同时，明确了我国潜叶蝇类害虫的种类以及6种优势潜叶蝇发生与危害的时空分布格局；2）通过形态和分子鉴定基本明确了我国潜叶蝇类害虫的寄生蜂的种类，以及系统明确了芙新姬小蜂等田间优势种的时空分布格局与动态及自然控害效应；3）确认了中国芙新姬小蜂为隐存种或复合种，至少存在7种隐存种；其中只有隐存种3同时存在孤雌产雌和两性繁殖2种繁殖模式，且隐3的两性繁殖寄生蜂中存在3个品系；4）解析了芙新姬小蜂隐存种/复合种（包括隐3的孤雌产雌品系和两性品系）的遗传分化以及与生态地理气候区域分布格局的关系；5）解析了孤雌产雌的孤雌产雌形成及其细胞学机制，证实孤雌产雌品系起源于或分化自隐3的两性品系；6）明确了寄生蜂孤雌品系和两性品系的田间竞争性共存与分化效应，阐明了其控害潜力和适应性及竞争演替的生物生态学基础。研究结果/结论和新发现不仅为寄生蜂物种形成与分化的深入研究提供了基础，在理论上丰富物种形成与进化理论，在应用实践上增强芙新姬小蜂为什么成为田间优势种和分布广、控害潜力大的理解，也为利用寄生蜂防控潜叶蝇的应用提供了指导。