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

大多数食草性昆虫只以一种或几种寄主植物为食，尽管当食物植物在空间或时间上稀缺时，能够使用多个寄主植物具有明显的优势。生态学研究已经对这种特化的产生和维持产生了相当大的洞察力，但人们对饮食广度变化的长期持久性和后果知之甚少。例如，专业化是一条死胡同吗？关于通才物种种群内的专门化过程如何，甚至是否与物种形成和专门化物种有关的证据较少。研究生Geoffrey Morse在Brian Farrell博士的指导下，将使用DNA序列数据来：(1)重建种子甲属Stor(Bruchidae)的系统发育；(2)研究姊妹物种S.limbatus Horn(一种多面手种子捕食者)和S.Beali Johnson(一种专业取食者)种群的遗传关系。第一个方面将检验关于资源专业化变化的进化后果的假设。第二个方面将检验有关植食性昆虫物种形成性质的假设，以及与饮食广度差异的种群遗传相关的假设。洞察昆虫如何成为专家或多面手，以及这些不同习性的进化后果，对进化生物学、保护生物学和农业昆虫学等领域都有影响。通过为定子寄主利用的进化生态学提供一个明确的历史视角，本研究将有助于综合生态和进化对多样性和资源利用的解释。

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.