西花蓟马温室品系和羽扇豆品系的空间分布格局及遗传分化机制

According to the competitive exclusion principle, two species cannot occupy the same niche or cannot share the same niche for a long time. The greenhouse strain and lupine strain of Frankliniella occidentalis invaded China simultaneously. Field investigations indicated that the population ratios of the greenhouse strain to lupine strain differ in different geographic regions. Consequently, the damages caused by this thrips are different. However, the spatial distribution pattern, habitat type and host plant species are still keeping unclear. In the present study, double gene markers, mtDNA COI and rDNA 28S, techniques of reproductive biology and population ecology, population genetics and ecological adaptability simulations will be used. Subsequently, taxonomic status of the greenhouse and lupine strain of this thrips will be clarified, i.e., are they two strains of one species that can mate each other freely or are different cryptic species. The technical systems of SS-PCR for specific detection of the greenhouse strain or lupine strain will be established. The dynamics of competition and succession between both strains will be determined under the conditions of different combinations of temperature and relative humidity as well as under different population ratios of greenhouse strain to lupine strain, and the dominant strain will be defined. A labeling technique based on double genes will be established and the synergic relationships between the genetic diversity and differentiation of both strains and adaptability to ecological environment will be investigated. The differentiations of host plant species, climatic ecological niche and gradient of environmental adaptation of both strains will be analyzed. The results should be significant in clarifying the mechanisms of spatial distribution pattern and population succession of the two strains as well as in development of regional target management measures of the thrips. Furthermore, the results should be useful in revealing the mechanism of ecological adaptation and population formation of this thrips species and in rich the theory of ecological niche differentiation.

竞争排斥原理认为，两个物种/亚种及以下的分类阶元不能同时或长时间共享同一生态位。针对西花蓟马的温室品系和羽扇豆品系同时侵入我国，空间分布格局、生境类型和寄主谱不清楚的问题，本项目采用mtDNA COI和rDNA 28S双基因标记技术以及生殖生物学、种群生态学、种群遗传学和生态适应性模拟的技术与方法，首先研究确定西花蓟马的温室品系和羽扇豆品系是否具有生殖隔离现象，建立品系特异性检测技术；同时通过室内生境模拟实验，阐明两个品系在不同温湿度组合和不同种群比例的演替规律和优势入侵品系；然后分析探讨两个品系不同地理种群双基因遗传多样性和遗传分化，及其与主要生态因子的相关性；进而，明确两个品系的寄主谱、气候生态位分化和环境适应梯度。研究结果对明确西花蓟马两个品系的空间分布格局及其种群演替机制，制定区域性靶向防控措施具有重要意义，并将有助于深入揭示西花蓟马的生态适应性和种群形成机制，丰富生态位分化理论。

西花蓟马原产于美国西北部，可危害60多科500多种植物，除直接危害外，还是多种农作物病毒的传播媒介；近30年来随国际贸易的发展迅速蔓延，在五大洲69个国家和地区普遍发生，并已造成严重经济损失，是一种全球最具经济重要性的农业蓟马类害虫。针对西花蓟马温室品系和羽扇豆品系同时入侵我国，空间分布格局、生境类型和寄主谱不清楚，难以有效防控的问题，在前期工作已明晰西花蓟马主要入侵区域和可能入侵来源地的基础上，采用双基因标记技术以及生殖生物学、种群遗传学等技术方法，首先研究确定西花蓟马的温室品系和羽扇豆品系分类地位，建立品系特异性快速检测技术体系；同时，通过室内不同温湿度组合的生境模拟实验，明确不同气候生态环境下两个品系的空间分布格局及共存的演替规律和优势入侵品系；然后采用双基因标记技术，通过Shannon信息指数、Nei指数以及基因流、固定指数、遗传距离分析等，研究揭示各品系群体遗传多样性和品系间遗传分化以及与主要气候生态因子的相关性；在此基础上，通过实地系统调查与数据采集和生态适应性模拟，明确两个品系的寄主植物种类、生态位分化及环境适应梯度。结果显示，西花蓟马的羽扇豆品和温室品系可自由交配，并能产生具有繁殖能力的后代，应为同一物种的不同品系或生态型；建立的一步双重PCR快速检测技术体系，可同时鉴定温室品系和羽扇豆品系；不同温湿度组合条件下共存竞争显示，羽扇豆品系优于温室品系，但其具体的种群竞争机制/机理尚需进一步研究；多基因标记分析结果显示，区域间种群遗传差异不明显，且种群遗传结构未形成明显的地理分布格局；进一步的系统调查结果表明，耕作地寄主植物上仅有西花蓟马的温室品系发生，而非耕作地寄主植物上温室品系和羽扇豆品系均有发生。研究结果将有助于深入揭示西花蓟马两个品系的种群分布格局形成机制，丰富生态位分化理论，并从实际上指导西花蓟马区域性靶向防控策略的制定。同时，本研究体系可为类似研究提供参考和借鉴。