Phylogenomics, Classification, and Revisionary Studies of Meniscus Midges (Diptera: Dixidae)

水生昆虫是营养物加工和水净化的贡献者，是生态研究和环境监测评价的模式生物，也是脊椎动物捕食者的猎物。后者的结果是，许多鱼在休闲钓鱼中被视为诱饵或人工诱饵（即“苍蝇”）的模型。双翅目，或“真蝇”，构成了水生昆虫多样性的很大一部分。Dixidae，一个这样的家庭通常被称为“半月板蠓”，是本研究的重点。这些像蚊子一样的苍蝇以其独特的幼虫而闻名，这些幼虫适应生活在岩石或植被周围的空气-水界面（因此得名）。它们经常在水面上横向游动或以典型的u形姿势休息。与其他类群相比，Dixidae受到科学家的关注要少得多。这在一定程度上是由于缺乏医学重要性和缺乏家庭分类学专家。此外，对dididae的研究历史上主要集中在区域动物群上，而不是全球的，更全面的治疗，导致我们的知识存在很大差距。因此，Dixidae的分类学是混乱的，而且解决得很差，而且对大多数物种的自然历史知之甚少。如果不加以纠正，这一困境将严重阻碍今后对家庭的研究。解决方案是基于综合形态学和分子系统发育研究的结果，对目前世界二甲科的分类进行全面检查。更深入地了解双翅虫的进化不仅本身就很重要，而且还很有价值，因为它有助于深入了解它们吸血的致病近亲：蚊子、黑蝇和叮咬的蠓的进化。广泛的培训学生和早期职业科学家与一般和分子生物学，生物信息学和系统发育相关的当前和新兴技术将纳入本研究，使他们能够应对21世纪生物学家面临的快速发展的挑战。一个健全的系统发育假说将有助于稳定didididae的分类和颁布未来的研究。本研究所需的标本将通过博物馆借阅和必要的实地考察获得。目前的分类困境和公众对这个科的认识极其有限，将通过完成以下研究和推广目标来纠正：(1)完成整个科（第1层：超特异群）和目标亚支（第2层：超特异群）的彻底系统修订；新北极Dixa属（Dixella， gondwana属Nothodixa）采用形态学和系统基因组学相结合的方法，前者收集了卵后所有生命阶段的DNA序列，后者代表了核基因组中数百个基因的DNA序列；这些研究将产生基于形态学（二分类和多访问键、高分辨率摄影图像、详细插图、交互式3d模型）和基于分子（原始数据、序列比对、系统发育推断）的输出；(2)开发线粒体和细胞核dna指纹图谱资源，以便快速、可靠地鉴定世界物种；(3)完善和完成一种新的方法，利用参考作图方法以及相应的绘制前后生物信息学管道，从短读基因组文库中挖掘系统发育信息标记，所有这些都打算在用户友好的图形用户界面（GUI）设置中进行；(4)通过面对面和基于互联网的外展计划，培养对科学方法、批判性思维和以水生昆虫为模式生物的自然科学的欣赏，吸引那些可能很少接触科学的缺乏服务的年轻人。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Aquatic insects are contributors to nutrient processing and water purification, serve as model organisms in ecological research and environmental monitoring and assessment, and are prey items for vertebrate predators. As a consequence of the latter, many are valued as bait or models for artificial lures (i.e., “flies”) in recreational fishing. Order Diptera, or “true flies”, comprises a substantial portion of aquatic insect diversity. Dixidae, one such family commonly known as “meniscus midges”, are the focus of this study. These mosquito-like flies are best known for their unique larvae, which are adapted to live at the air-water interface (hence the common name) surrounding emergent rocks or vegetation. They are often seen swimming laterally on the water’s surface or resting in a characteristic U-shaped posture. Dixidae, when compared to related groups, have received far less attention from scientists. This is due in part to the lack of medical importance and a paucity of taxonomic experts for the family. Furthermore, studies of Dixidae have historically focused on regional faunas, rather than global, more comprehensive treatments, leading to large gaps in our knowledge. As a result, the taxonomy of Dixidae is confusing and poorly resolved, and relatively little is known about the natural history of most species. If left uncorrected, this quagmire represents a serious impediment to future research on the family. The solution is a complete overhaul of the current classification of world Dixidae based upon results of an integrative morphological and molecular phylogenetic study. A greater understanding of dixid evolution is not only important in its own right, but also valuable because it lends insight into the evolution of their blood feeding, pestiferous relatives: mosquitoes, black flies, and biting midges. Extensive training of students and early career scientists in current and emerging technologies with relevance to general and molecular biology, bioinformatics, and phylogenetics will be incorporated throughout this study so they will be poised to meet rapidly developing challenges facing 21st century biologists. A robust phylogenetic hypothesis will significantly aid in stabilizing the classification of Dixidae and promulgating future research. Specimens needed for this study will be acquired through museum loans and necessary fieldwork. The current taxonomic quandary and the extremely limited public awareness of this family will be remedied by completing the following research and outreach objectives: (1) complete thorough systematic revisions of the entire family (Tier 1: supraspecific groups) and targeted subclades (Tier 2: Nearctic genera Dixa & Dixella, Gondwanan genus Nothodixa) using a combined morphological and phylogenomic approach, the former gleaned from all life stages after the egg and the latter DNA sequences representing hundreds of genes from the nuclear genome; these studies will yield morphology-based (dichotomous and multi-access keys, high-resolution photographic images, detailed illustrations, interactive 3-D models) and molecular-based (raw data, sequence alignments, phylogenetic inferences) outputs; (2) develop DNA-fingerprinting resources, both mitochondrial and nuclear, to allow for rapid, reliable identification of world species; (3) refinement and completion of a novel approach to mine phylogenetically informative markers from short-read genomic libraries using a reference mapping approach as well as accompanying pre- and post-mapping bioinformatics pipelines, all of which are intended to be carried out within a user-friendly graphical user interface (GUI) setting; and (4) through in-person and internet-based outreach programs, foster an appreciation for the scientific method, critical thinking, and natural sciences using aquatic insects as model organisms, engaging predominantly underserved youths who may otherwise receive little exposure to science.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.