物种的分布格局和遗传结构受第四纪冰期的深刻影响，亲缘地理研究已描绘了许多温带物种的第四纪冰期避难所位置及冰期后扩散路线，第四纪温度和(或)降水变化也驱动热带、亚热带物种大范围迁移，但相关研究很少。世代周期较长的多年生植物的叶绿体DNA变异积累较慢，不易追踪这些物种对第四纪气候波动的响应，世代周期较短的强制性寄生或共生的物种可作为代理材料提供精准的信息。本项目拟以强制性共生物种薜荔及其传粉小蜂以及传粉小蜂的内生菌Wolbachia为对象，利用微卫星标记、叶绿体DNA和(或)线粒体DNA标记分析薜荔和传粉小蜂的遗传结构，研究Wolbachia感染对传粉小蜂遗传分化的影响，通过亲缘地理格局比较和生态位模型模拟，确定薜荔-传粉小蜂体系第四纪冰期避难所及冰期后扩散路线，为阐明第四纪冰期对亚热带植物的影响，预测种间关系在气候变化情景下的适应性和变化趋势提供科学依据。

Distribution and genetic structure of species are deeply impacted by climate oscillations of the Quaternary. Glacial refugia and post-glacial colonization routes of many temperate species have been revealed by phylogeographical studies; however, we still know little about subtropical or tropical species, which, obviously, have also been influenced by climate oscillations. Perennial plants have a long life history and cpDNA variation was accumulated slowly. Thus it is not easy to obtain a clear phylogeographic pattern and correctly infer the glacial refugia and post-glacial colonization routes. The obligate parasites and mutualistic species, which have much shorter life histories, provide ideal proxies for these long-lived species. ..Figs (Ficus, Moraceae) and their pollinating fig wasps form one of the most specific obligate mutualisms. Fig wasps depend on figs to provide larval feeding sites (in galled ovules), while figs depend on fig wasps to transfer pollen between figs. However, fig wasps are frequently infected by the endosymbiont, Wolbachia, which can influence genetic diversity and differentiation of their hosts. ..In the proposed project, an obligate mutualism - Ficus pumila and its pollinating wasps - and Wolbachia of pollinating wasps will be used as the focal system. We will use molecular markers (nDNA microsatellites, and mtDNA, cpDNA, or nDNA sequences) to study genetic structure of F. pumila and its pollinating wasps. We will check infection rate of Wolbachia in pollinating wasps, and study the role of Wolbachia in genetic differentiation of the pollinating wasps. Combining comparative phylogeographic patterns and niche model of F. pumila, we will identify the glacial refugia for these species and their post-glacial colonization routes. The results of this study will provide evidence of impacts on subtropical plants by the Quaternary climate oscillations, and will be useful for predicting the adaptation and changes of specific interactions under prejected climate changes.