榕树-传粉者共生体系的协同进化与系统学研究进展及展望

 榕树-传粉者共生体系是目前植物与昆虫协同进化研究中的典型模式之一。国内外已经开展了大量的相关研究，从不同方面探讨了其特殊的一一对应的共生关系。榕树-传粉者的专一性互惠共生关系中蕴含了与系统发育有关的多因子协同进化的机理，因此，进行系统发育研究将有助于更好地揭示榕树-传粉者的协同进化历史和理解二者的专一性互惠共生关系。本文简单地介绍了目前榕树及其传粉者共生体系的研究状况之后，论述了榕树-传粉者协同进化的系统发育分子生物学研究成果。同时针对国际上在榕属植物的传统的系统与分类研究中存在的一些分歧及榕树传粉者亚科分类不匹配等问题，回顾了榕属的分类研究进展及其与传粉者的关系。最后，结合我国榕树与传粉者共生体系的研究状况对我国榕属的重新分类和系统发育研究作了展望。

BRIEF REVIEW OF FIG-POLLINATOR COEVOLUTION AND FICUS CLASSIFICATION

Ficus is the keystone plant in tropical forests, and it also occurs in subtropical and even temperate areas. More than 700 species in the genus Ficus (Moraceae: Ficus ) and their species_specific pollinator, the fig wasp, (Chalcidoidae: Agaonidae) has been discovered. The interactions between them, which have become an obligate mutualist relationship, have a very long evolutionary history. Pollen dispersal in figs is completely dependent on fig wasps, which enter the syconium where viable seeds are produced. Fig pollinators are uniquely dependent on the fig for the completion of their life cycle. Each fig species attracts its own species of fig wasp by emitting specific volatile compounds during their receptive period and these wasps lay their eggs in the developing ovary of the host fig species. As ovipositing female wasps simultaneously carry pollen from other syconia and pollinate figs actively or passively, they show peculiar morphological and behavioral adaptations to figs and a life cycle highly synchronous with fig inflorescence. Such specialization and interactions make diversity in species, genetics, morphology and behavior in pollinators and their host plants an exciting example for studying interspecific coevolution. Although fig_pollinator symbiosis is now widely regarded as a model system of plant_insect coevolved mutualism, little is known about the history and process of their interactions. Current experiments and observations have suggested the fig/fig wasp obligate mutualism (this is not a complete sentence but I am not sure what the author is trying to say here). However, present fig and fig wasp classifications, which are based on morphological characteristics and their interactions, are still incomplete and controversial. This short review summarized the knowledge and questions on coevolved mutualism, the molecular phylogeny of fig/fig pollinator symbionts and the traditional classification of Ficus . Studies on the interactions between fig/fig pollinator and re_classification of Ficus in China based on molecular phylogeny were also discussed. Research on the phylogeny of about 100 species of fig trees, which mainly occur in tropical and subtropical areas in China, has just started and only a few reports on fig pollination biology and ecology exist. Much work should be done to make a thorough study of both symbiotic partners. Though systematic classification of Ficus is the basis of the coevolutionary study, application of molecular phylogeny is also necessary and feasible, which will promote further research and understanding of plant_insect coevolution in China.