Mechanisms of speciation in Southeast Asian ant-plants of the genus Macaranga (Euphorbiaceae) associated with Crematogaster ants

与火腹蚁相关的东南亚大戟属蚂蚁植物的物种形成机制

• 批准号: 5362765
• 负责人: Dr. Frank R. Blattner
• 金额: --
• 依托单位: Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2002
• 资助国家: 德国
• 起止时间: 2001-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5362765?language=en
• 关键词: Mechanisms; speciation; Southeast; Asian; ant

Biotic interactions between organisms can be a crucial factor driving diversification and speciation. We are investigating myrmecophytic ant-plant associations as a model system for the evolution of mutualistic interactions in general. In myrmecophytes, the ants benefit from food and preformed nest sites supplied by their host whereas the host plants benefit from protection against herbivores and vines. The most prominent ant-plant system of the palaeotropics consists of the pioneer tree genus Macaranga and its manifold associations with Crematogaster-ants. Our previous work has shown that genetic distances between myrmecophytic Macaranga species are small, suggesting a recent radiation. We envisage two hypotheses that may account for this observation. First, the obligatory symbiosis with ants reduces gene flow among plant populations, resulting in population differentiation, and eventually allopatric speciation. Alternatively, the acquisition of mutualistic ant partners served as a key innovation which enhanced the fitness of the plant partners in certain habitats, thereby promoting ecological differentiation. To test the first of these hypotheses, we will initiate a comparative study on two pairs of myrmecophytic vs. non-myrmecophytic Macaranga species to analyse (1) population structure and the extent of gene flow using nuclear microsatellite markers, and (2) historic population divergence (phylogeography) based on chloroplast haplotypes.

生物之间的生物相互作用可能是驱动多样化和物种形成的关键因素。我们正在研究肉豆蔻型蚂蚁植物的关联，作为一般相互作用进化的模型系统。在Myrmepophytes中，蚂蚁受益于寄主提供的食物和预先形成的巢穴，而寄主植物则受益于对草食动物和葡萄藤的保护。古植物学中最突出的蚂蚁植物系统由先锋树属Macaranga及其与Crematogaster-ant的歧管关联组成。我们以前的工作表明，肉豆蔻麦卡兰加物种之间的遗传距离很小，这表明最近的辐射。我们设想两个可能解释这一观察结果的假设。首先，与蚂蚁的强制性共生减少了植物种群之间的基因流动，从而导致种群分化，并最终导致异植物形成。另外，对共同抗体伙伴的获取是一种关键创新，从而增强了植物伴侣在某些栖息地的适应性，从而促进了生态分化。为了检验这些假设的第一个假设，我们将通过两对肉豆蔻菌与非杂菌性麦卡兰加物种进行比较研究，以分析（1）种群结构和基于核微卫星标记的基因流量，以及（2）基于叶绿素的历史种群差异（2）历史种群人群差异（Phylogeography）。