DISSERTATION RESEARCH: Understanding the Evolutionary Patterns Contributing to Species-specific Male and Female Genitalia in a Group of Scarab Beetles

本论文改进拨款的重点是解决物种特异性雄性和雌性生殖器如何在一组圣甲虫中进化。这是一种多样化的大型棕色甲虫，由北美大约250种组成，在最初的外部形态检查中，它们看起来都非常相似。然而，每个物种都有独特的雄性和雌性生殖器，这是分类学家用来区分它们与近亲的。本研究将阐明美国东部地区圣甲虫群中一个物种复杂的关系。推断的关系将允许研究人员测试男性和女性生殖器特征的生殖器进化假设，并确定男性和女性生殖器是否沿着相似的轨迹进化。此外，将对同一物种内的受精成功率进行分析，以确定雄性和雌性生殖器形状的种内变异是否与父系成功相关。该项目的这两个方面将使研究人员能够确定物种之间发生的进化过程是否与物种内部发生的进化过程一致。本研究将为实证检验生殖进化在一夫多妻昆虫种群的物种形成和多样化中所起的作用提供必要的基础。这项研究将为研究生提供动物行为、分子系统学和形态计量学领域的经验，并包括与康奈尔大学、达特茅斯学院和阿默斯特学院的研究人员的跨大学合作。此外，通过这项研究收集的信息和数据将用于为这一特殊的圣甲虫群体建立一个可公开访问的物种数据库。此外，本研究的各个方面都有本科生助理，并为本科生提供了获得实地和实验室工作经验的机会，并学习如何跨多个学科整合数据。

The focus of this dissertation improvement grant is to address how species-specific male and female genitalia evolve in a group of scarab beetles. This is a diverse group of large, brown beetles comprised of approximately 250 species in North America which all look extremely similar upon initial examination of their external morphology. However, each species has unique male and female genitalia, which are used by taxonomists to distinguish them from close relatives. This research will elucide the relationships of a species complex within this group of scarab beetles from eastern regions of the United States. The inferred relationships will allow the investigators to test hypotheses of genitalic evolution of both male and female genital characters and determine whether male and female genitalia are evolving along similar trajectories. In addition, fertilization success analyses within one species will be conducted to determine whether intraspecific variation of male and female genitalic shapes is correlated with paternity success. These two aspects of the project will allow the investigators to determine whether evolutionary processes occurring among species are concordant with the evolutionary processes occurring within species. This research will provide the foundation necessary to empirically test the role genitalic evolution plays in the speciation and diversification of a polygamous insect group. This research will provide a graduate student with experience in the fields of animal behavior, molecular systematics, and morphometrics, and includes cross-university collaborations with researchers at Cornell, Dartmouth, and Amherst College. In addition, information and data compiled through this research will be used to develop a publicly accessible species database for this particular group of scarab beetles. In addition, all aspects of this research incorporate undergraduate assistants, and provides the opportunity for undergraduates to gain experience doing both field and lab work and to learn how to integrate data across multiple disciplines.