DISSERTATION RESEARCH: The Lost Herbivores: Phylogeny and Floral Host Preferences of Callandrena Bees (Hymenoptera: Andrenidae: Andrena)

9902301 Simpson and Larkin Callandrena是新大陆的一个亚属。Andrena是蜜蜂中最大的属，有80种，全世界有1200多种。对DNA序列数据的初步分析对目前对该亚属的理解提出了质疑;种间关系与以前基于形态学所认为的不同，其他亚属的成员显然嵌套在Callandrena本身的系统发育中。在德克萨斯大学Beryl Simpson博士的指导下，研究生Leah Larkin将研究这群蜜蜂的生殖发育，强调线粒体和核基因序列是数据的主要来源，从墨西哥和美国的野外工作中收集的尽可能多的物种中取样。（遗传学），其结果将提供一个更好地了解一大群北美蜜蜂，并将有助于遗传学，目前缺乏，作为一个整体的安德雷纳。 从蜂群发生学，人们可以推断出哪些形态特征对于分类目的来说过于多变，这些信息可能适用于其他蜂群的研究。 此外，巢发生学将允许进一步研究行为和适应，包括季节活动，巢建筑和巢寄生虫。 的亚属Callandrena也作为一个模型系统的蜜蜂的饮食选择在花粉觅食的进化研究，但在这些行为的进化变化一直不服从分析没有一个强大的同源性，以指导解释主机的变化和方向的变化。蜜蜂从花中收集花粉来提供它们的巢，并且在这样做的过程中表现出一系列的寄主特异性，从通才（许多不同的植物物种，称为多选择性）到专家（少数物种，通常在一个植物家族中，称为寡选择性）到罕见的单种情况（使用单一植物物种）。虽然这种行为类似于一般食草昆虫的寄主选择，但其进化却知之甚少。将在墨西哥和美国的野外研究Callandrena众多物种的花粉选择，并且将从主要收藏中保存的蜜蜂的博物馆标本中的花粉载量的分析中推断。这项研究将是第一个彻底评估花粉寄主选择在蜜蜂的进化背景下。这项研究将提高对蜜蜂行为进化和草食动物进化的理解。

9902301Simpson and Larkin Callandrena is a New World subgenus of ca. 80 species in Andrena, the largest genus of bees, with over 1200 described species worldwide. Preliminary analysis of DNA sequence data casts doubt on the current understanding of the subgenus; species relationships are different from what was previously thought based on morphology, and members of other subgenera are apparently nested within the phylogeny of Callandrena itself. Graduate student Leah Larkin, under the direction of Dr. Beryl Simpson at the University of Texas, will be studying the phylogeny of this group of bees, emphasizing mitochondrial and nuclear gene sequences as primary sources of data, sampled from as many species as can be collected from field work in Mexico and the U.S. The estimate of evolutionary relationships (phylogeny) which results will provide a better understanding of a large group of North American bees, and will contribute to a phylogeny, currently lacking, of Andrena as a whole. From the phylogeny, one can infer which morphological characters are too variable for classification purposes, information which may be applicable to the study of other bee groups. Additionally, the phylogeny will permit further studies of behavior and adaptation, including seasonal activity, nest architecture, and nest parasites. The subgenus Callandrena has also served as a model system for the study of the evolution of bee diet choice in pollen foraging, but the evolutionary changes in these behaviors have not been amenable to analysis without a robust phylogeny to guide interpretation of host shifts and direction of change. Bees collect pollen from flowers to provision their nests, and in so doing exhibit a range of hostplant specificity from generalist (numerous and different plant species, called polylectic) to specialist (few species, usually within a single plant family, called oligolectic) to rare cases of monolecty (use of a single plant species). While this behavior is analogous to hostplant choice in herbivorous insects in general, its evolution is poorly understood. Pollen choice in numerous species of Callandrena will be studied in the field in Mexico and the U.S., and will be inferred from analysis of pollen loads in museum specimens of bees maintained in major collections. This study will be the first to evaluate thoroughly pollen host choice in an evolutionary context in bees. The study will improve understanding of the evolution of bee behavior and the evolution of herbivory in general.