RUI: Generating the Entangled Bank: Biogeography and Host Use in a Hawaiian Herbivore Radiation

AbstractBrownDEB 0445086。生物学家长期以来一直在研究岛屿辐射，以了解适应和地理隔离如何相互作用以产生生态多样性。夏威夷群岛一直是进行这种物种形成研究的一个富有成效的地方，因为它与大陆移民来源的极端隔离，以及它高度多变的环境，刺激了为数不多的成功殖民它的谱系的惊人辐射。该项目研究了26种以上夏威夷麻蝇的多样化机制和速度，这些麻蝇可能是在不到300万年的时间里从一个单一的殖民祖先辐射出来的。这些昆虫以只在夏威夷发现的植物物种为食，包括夏威夷银剑联盟的大多数成员，这是适应性辐射的经典模型；许多以种子为食，因此对寄主植物的繁殖有直接影响，其中一些是联邦濒危物种。乔纳森·布朗博士将与才华横溢的本科生合作，进行实地和实验室研究：(1)调查整个群岛可能的植物寄主，以确定所有物种的地理范围和寄主使用模式；(2)基于多个基因序列的信息，确定所有物种之间的进化关系。这些进化关系将被用来研究地理隔离与不同寄主植物在物种形成过程中的适应性变化的作用。这些结果将为未来行为和形态特征的进化研究提供一个框架，例如，黑色素翅膀模式，这是一种用于识别伤寒蝇和其他一些类群的关键特征。了解这些特征的进化将有助于更好地了解这个多样化的昆虫家族，其中包括许多具有经济重要性的害虫物种。了解像夏威夷这样的群岛上的进化过程对于理解它们的保护价值很重要，尤其是考虑到它们独特的本土物种目前面临的威胁。该研究项目还将为几名本科生提供夏季研究经验，展示有机、分子和保护生物学跨学科研究的实力。格林内尔学院的学生将通过美国国家科学基金会支持的核心生物学课程为这些经历做好充分准备，该课程强调以研究为基础的学习和跨生物分支学科的整合。布朗博士致力于招募参加格林内尔新科学项目的研究生，这是一个旨在鼓励代表性不足的群体追求科学事业的创新项目。与他以前的工作一样，学生将成为收集、分析和传播研究结果的全面合作伙伴。通过在以探究技能为中心的生物学课程中提供独立的研究机会，该项目将延续布朗博士和格林内尔学院将科学研究融入广泛而有意义的文科教育的成熟传统。

AbstractBrownDEB 0445086. Biologists have long studied island radiations to understand how both adaptation and geographic isolation have interacted to generate ecological diversity. The Hawaiian archipelago has been a productive place to undertake such speciation studies, because its extreme isolation from continental sources of immigrants and its highly variable environments have spurred spectacular radiations of the few lineages to have successfully colonized it. This project investigates the mechanisms and tempo of diversification of the 26+ species of Hawaiian tephritid flies, which have likely radiated from a single colonizing ancestor in less than 3 million years. These insects feed on plant species found only in Hawaii, including most members of the Hawaiian silversword alliance, a classic model of adaptive radiation; many feed on the seeds and thus have a direct impact on reproduction of their host plants, some of which are federally endangered species. In collaboration with talented undergraduate research students, Dr. Jonathan Brown will undertake field and laboratory studies to (1) survey likely plant hosts from across the archipelago to determine the geographic range and mode of host use for all species; and (2) determine the evolutionary relationships among all the species, based on information from multiple gene sequences. These evolutionary relationships will then be used examine the role of geographic isolation vs. adaptive changes to different host-plants in the speciation process. The results will provide a framework for future studies of the evolution of behavioral and morphological traits, e.g., melanin wing patterns, a key trait used to identify tephritids and some other groups of flies. Understanding the evolution of these traits will contribute to a better understanding of this diverse family of insects, which includes many pest species of economic importance. Knowledge of the evolutionary processes that play out on island archipelagos like Hawaii is important for understanding their conservation value, especially given current threats to their unique native species. This research project will also provide several undergraduate students with summer research experiences that demonstrate the strength of interdisciplinary research in organismal, molecular, and conservation biology. Students will be well prepared for these experiences via an NSF-supported core biology curriculum at Grinnell College that emphasizes research-based learning and integration across biological subdisciplines. Dr. Brown is committed to recruiting research students who have participated in Grinnell's New Science Project, an innovative program designed to encourage under-represented groups to pursue scientific careers. As in his previous work, students will be full partners in the gathering, analysis and dissemination of the results of the study. By providing independent research opportunities within a biology curriculum centered on skills of inquiry, this project will continue both the Dr. Brown's and Grinnell College's proven tradition of integrating scientific research into a broad and meaningful liberal arts education.