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.

生物体之间的生物相互作用可能是推动多样性和物种形成的关键因素。我们正在研究蚂蚁与植物的共生关系，将其作为互惠互动进化的一个模型系统。在苔藓植物中，蚂蚁受益于其宿主提供的食物和预制的巢穴，而宿主植物受益于对食草动物和藤本植物的保护。古热带地区最突出的蚂蚁-植物系统由Macaranga属及其与火化蚂蚁的多种群丛组成。我们之前的工作表明，桃金娘属物种之间的遗传距离很小，这表明最近发生了一次辐射。我们设想了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，导致种群分化，最终形成异地物种。或者，收购互惠互利的蚂蚁伙伴是一项关键的创新，它增强了植物伙伴在某些生境中的适合度，从而促进了生态分化。为了验证第一个假设，我们将启动对两对桃金娘和非桃金娘的比较研究，以分析(1)利用核微卫星标记的种群结构和基因流动的程度，以及(2)基于叶绿体单倍型的历史种群分化(系统地理)。