Dissertation Research: Phylogenetics and Resource Specialization in the Seed Beetle Genus Stator (Coleoptera: Chrysomelidae: Bruchinae)

[00:73 . 33]大多数食草昆虫只以一种或极少几种寄主植物为食，尽管当食物植物在空间或时间上稀缺时，它们能够利用多种寄主的明显优势。生态学研究已经对这种专业化的产生和维持产生了相当深刻的见解，但对饮食广度变化的长期持久性和后果却知之甚少。例如，专门化是一条死胡同吗？关于通才物种种群内的特化过程如何或是否与物种形成和专才物种有关的证据较少。在Brian Farrell博士的指导下，研究生Geoffrey Morse的研究将利用DNA序列数据：(1)重建种子甲虫属定子（Bruchidae科）的系统发育；(2)研究姐妹物种S. limbatus Horn（通才种子捕食者）和S. beali Johnson（专业喂食者）种群的遗传关系。第一个方面将检验有关资源专业化变化的进化后果的假设。第二个方面将测试关于食植物昆虫物种形成的本质的假设，以及饮食宽度差异的种群遗传相关性。深入了解昆虫如何成为专家或通才，以及这些不同习性的进化结果，对进化生物学、保护生物学和农业昆虫学等领域都有影响。通过对定子寄主利用的进化生态学提供一个明确的历史视角，本研究将有助于将多样性和资源利用的生态和进化解释结合起来。

0073330Farrell and Morse Most herbivorous insects feed on only one or very few kinds of hostplants, despite the apparent advantages of being able to use multiple hosts when foodplants are scarce in space or time. Ecological research has generatedconsiderable insight into the generation and maintenance of this specialization, but the long term persistence and consequences of variation in diet breadth are poorly understood. For example, is specialization a dead end? There is less evidence on how or even whether the process of specialization within populations of generalist species is connected to speciation and specialist species. Research by graduate student Geoffrey Morse, under the direction of Dr. Brian Farrell, will use DNA sequence data to: (1) reconstruct the phylogenyof the seed beetle genus Stator (family Bruchidae); and (2) examine the genetic relationships of populations of the sister species S. limbatus Horn (a generalist seed predator) and S. beali Johnson (a specialist feeder). The first aspect will test hypotheses concerning the evolutionary consequences of changes in resource specialization. The second aspect will test hypotheses concerning both the nature of speciation in phytophagous insects, and the population geneticcorrelates of divergence in diet breadth. Insights into how insects become specialists or generalists, as well as into the evolutionary consequences of these different habits, have implications for fields as diverse as evolutionary biology, conservation biology, and agricultural entomology. By providing an explicit historical perspective on the evolutionary ecology of host use in Stator, this research will contribute to the synthesis between ecological and evolutionary explanations of diversity and resource use.