DISSERTATION RESEARCH: The species versus subspecies conundrum: quantitative assessment from integrating multiple data types under a single Bayesian framework in Hercules beetles

在不同的生物群体中，种和亚种的命名方式是否存在差异？如果是这样的话，生物多样性调查可能会有偏见，可能低估或高估物种多样性的水平。研究人员将使用来自两组大力士甲虫（Dynastes属）的遗传和形态数据来解决这个问题，北美和南美之间的多样性模式不同，这可能是因为物种与亚种名称的不同应用。通过对观察到的分类群之间的差异进行定量评估，研究人员将测试物种之间的遗传和形态差异是否比亚种之间的差异更明显。通过这项研究获得的知识将展示如何在不同的生物群体和地理区域之间一致，客观和定量地评估分类学。这种标准化方法对于避免物种多样性生物多样性调查和确定需要养护的分类群方面的潜在偏见至关重要。一名研究生将接受各种系统方法的培训，并将建立一个网站，广泛传播研究人员开发的物种划界方法，虽然最近相当多的研究集中在客观划界物种的定量方法上，但一个被忽视但同样重要的问题是被划界的分类实体的性质。一个基于模型的方法将被应用到测试是否大力士甲虫的物种和亚种是统计上等效的。研究人员还将测试目前公认的分类群是否代表物种形成连续体的不同点，以及分化水平是否符合基于分类群分化时间的预期。由于表型和遗传数据都将在贝叶斯框架中进行分析，因此研究将能够确定数据类型之间物种边界的差异是否反映了（i）与谱系分裂的实际历史不一致，或（ii）不同数据类型中分类群之间分化所需时间的差异。（具体而言，遗传与形态数据的进化变化率不同）。这项工作推进了生物多样性研究，使其有可能的理论观点的物种形成作为一个连续的过程，以定量的方式应用于实践中，生物多样性的分类等效单位可以确定在不同的地理区域和不同群体的生物物种多样性的比较。

Are there differences in how species and subspecies are designated among different groups of organisms? If so, surveys of biodiversity could be biased, potentially either under- or over-estimating levels of species diversity. Researchers will address this issue using genetic and morphological data from two groups of Hercules beetles (genus Dynastes), where diversity patterns differ between North and South America, perhaps because of differing applications of species versus subspecies designations. Through quantitative assessments of the observed differences among taxa, researchers will test if genetic and morphological differences between species are more pronounced than those found among subspecies. Knowledge gained by this research will demonstrate how taxonomy can be assessed consistently, objectively, and quantitatively across distinct groups of organisms and between geographic regions. Such a standardized approach is critical to avoiding potential biases in biodiversity surveys of species diversity and the identification of taxa in need of conservation. One graduate student will be trained in diverse systematic methods and a website will be established to broadly disseminate the species delimitation methods developed by the researchers.While considerable recent research has focused on quantitative methods for objectively delimiting species, an overlooked, but equally important, issue regards the nature of the taxonomic entities being delimited. A model-based approach will be applied to test whether species and subspecies of Hercules beetles are statistically equivalent. Researchers will also test if currently recognized taxa represent different points along the speciation continuum and whether levels of differentiation fit with expectations based on the time taxa have been diverging. Because both phenotypic and genetic data will be analyzed in a Bayesian framework, the research will be able to determine whether disagreements in species boundaries among data types reflect (i) discordance with the actual history of lineage splitting, or (ii) differences in the amount of time required for differentiation to become apparent among the taxa in different data types (specifically, different rates of evolutionary change in genetic versus morphological data). This work advances biodiversity studies by making it possible for the theoretical view of speciation as a continuous process to be applied in practice in a quantitative manner such that the taxonomic equivalent units of biodiversity can be determined for comparisons of species diversity in different geographic regions and across different groups of organisms.