摘要
共生体系的长期维持引发了一系列进化问题,特别是共生双方的相互适应、协同进化成为进化理论的一大挑战。榕和传粉榕小蜂是目前所知的专性最强的共生体系之一,两者异常丰富的物种组成以及宿主多样的生活型为以上问题的研究提供了理想的体系。早期认为榕与其传粉小蜂间均为狭义协同进化,一对一原则在该体系中具有普适性。然而近年来发现越来越多的例外,特别是宿主转移现象在某些地区、某些榕属类群中的普遍存在,使榕及其传粉小蜂间严格的物种专一性及协同进化发生在物种水平的观点受到质疑,最近提出了一个新的协同进化模式来解释榕与其传粉小蜂的对应关系。榕与传粉小蜂间的进化模式说明两者间既有狭义的协同进化,也有发散协同进化关系,从而导致它们之间物种专一性不同。目前,两种协同进化模式在该系统中的相对重要性仍存在很大争议,不同地区、不同榕属类群中两者的物种专一性程度和产生原因可能有很大差异,榕与传粉榕小蜂系统的复杂性决定了不能将某些地区和某些类群的结论简单扩展,有关该体系协同进化主导模式的正确评判有待于对不同地区和不同榕属类群对应传粉小蜂的物种组成、来源方式,以及共生双方的系统发生关系进行更广泛、更深入的研究。
Mutualism is one of the most important ecological interactions,with strong influences on almost all levels of biological systems.Their long-term persistence raises many challenging evolutionary questions,especially those involving high-level coevolution and coadaptation.Figs and their pollinating wasps are among the most tightly integrated mutualisms known,and provide a model system for developing and testing theories of coevolution.Initial studies suggested specific coevolution between them,described as the famous rule of one fig one wasp.However,more and more exceptions have been revealed by recent studies,and cryptic species in pollinating wasps and host switching were found common in some regions and within some Ficus groups,inducing debates on the levels of species specificity and coevolution.A broad-sense coevolution model to describe the relationship of the related groups of figs and their pollinating wasps was proposed recently.The diverse relationships between figs and their pollinating wasps indicated coexistence of both specific and diffuse coevolution in this mutualism system,producing different species-specificity level.However,which model is the dominant one in this system is still keeping open.The species specificity could be tight or loose in different regions and fig groups involved.Consequently,the frequencies and mechanisms of breakdowns of the one-to-one rule within different fig groups as well as in different regions are essential for the understanding of the relative importance of the competing finer-scale cospeciation or broad-sense coevolution models.
出处
《生物多样性》
CAS
CSCD
北大核心
2010年第1期1-10,共10页
Biodiversity Science
基金
国家自然科学基金面上项目(30870361)
