Dissertation Research: The Evolution of Arboreal Carabid Beetles

[00:73 . 73]麦迪森等许多生物群体的多样性与新特征的进化有关，这些新特征有助于物种数量的爆炸性增长。在这种辐射中获得的适应具有特殊的功能和独特的进化史。一个物种日益多样化和逐渐专业化的例子可以在甲虫身上找到，通常被称为地甲虫，它们已经适应了树栖生活方式。研究生凯伦·奥伯在大卫·麦迪森博士的指导下，通过调查大类群Lebiomorpha的10个左右部落的代表性分类群，正在研究甲虫的树栖适应进化。来自马来西亚和马达加斯加的新藏品（后者由同事提供）将增加博物馆的馆藏，并为分子和形态学研究提供材料。形态学特征包括跗骨和爪的结构（与交配无关）、腿的长度和喙的形状，这可能涉及到对树栖生活的适应性变化。为了研究树栖carabids的起源和进化，我们将利用28S核糖体RNA基因和“无翼”核基因这两个基因的分子序列数据，重建lebiomorphs及其近亲的进化树。两者都显示出提供变异差异的希望，这将允许在lebiomorphs谱系之间进行区分。有了这些关系的进化史，人们可以研究生境从地栖到树栖的数量和方向，并探索与树栖生活有关的生态和形态特征的变化模式。

0073273Maddison and Ober The diversity of many groups of living organisms is related to the evolution of novel features that contribute to an explosive increase in the number of species. Adaptations acquired during such a radiation posses specialized functions and a unique evolutionary history. An example of increasing diversification of species and progressive specialization can be found in carabid beetles, commonly known as ground beetles, that have adapted an arboreal lifestyle. Graduate student Karen Ober, under the direction of Dr. David Maddison, is studying the evolution of arboreal adaptations in carabid beetles by surveying representative taxa across the 10 or so tribes of the large group Lebiomorpha. New collections from Malaysia and from Madagascar (the latter supplied by colleagues) will augment museum holdings and provide materials for molecular and morphological studies. Morphological features include tarsal and claw structures (independent of those associated with mating), leg length, and prorhorax shape, which may be involved in adaptive changes to arboreal life. To investigate the origin and evolution of arboreal carabids, an evolutionary tree of lebiomorphs and their relatives will be reconstructed using molecular sequence data from minimally two genes, the 28S ribosomal RNA gene and the nuclear gene 'wingless.' Both show promise of providing mutational differences that would allow discrimination among lineages of lebiomorphs. With the evolutionary history of relationships in hand, one can study the number and direction of habitat shifts from ground-dwelling to arboreality and explore patterns of changes in ecological and morphological features presumed to be associated with arboreal life.