Doctoral Dissertation Research: Phylogeny, Classification and Biodiversity of Robber Flies (Diptera: Asilidae) with Special Reference to Leptogastrinae

生物多样性研究具有巨大的科学和社会价值，特别是在生物多样性受到严重威胁的今天。本论文研究的是一类昆虫，全世界约有7000种被描述的昆虫，是种类最丰富的真蝇家族之一。盗蝇(Asilidae)很容易被识别，并作为昆虫捕食者发挥着重要作用。尽管许多科学出版物都涉及到这些苍蝇，但这些物种的进化关系仍然不清楚。本研究的重点是细腹亚科的种类，目前已知有462种。这一组是独特的，因为与狭窄的身体相关的特殊形态特征，很可能是适应草中的生活。许多其他种类的盗蝇也生活在草原和草原上，但缺乏一套如此独特的相似形态特征。该项目通过(1)提出关于蝗虫物种进化关系的充分证实的假设，(2)提供细腹蝇亚科物种的种类描述和识别检索表，以及(3)根据国际生物多样性保护热点分析细腹蝇亚科物种的分布和物种丰富度，从而加强对蝗虫的认识。这些发现将允许讨论与所有强盗苍蝇的栖息地偏好有关的特征进化，重点是草栖物种，并利用成年苍蝇的形态特征和DNA序列将它们与细腹蝇亚科物种进行比较。在东南亚进行了实地工作，以收集各种盗蝇进行分析，因为该地区拥有最不为人所知和采样的动物。参观了两个主要的自然历史博物馆，收藏着来自东南亚的Asilidae标本-英国伦敦和荷兰阿姆斯特丹-检查对鉴定新收集的材料具有特殊重要性的历史标本。在许多用于研究生物多样性危机的目标群体中，昆虫的代表总是不足。本论文项目将物种最丰富的苍蝇种群之一纳入生物多样性分析。向世界各地传播科学知识具有极其重要的意义。在该项目中汇编的物种描述和识别检索表正在以规定的印刷格式在科学期刊上以及万维网上作为综合生物多样性数据库发表，从而使世界各地的受众，包括昆虫学家和保护生物学家，都能获得这方面的知识。一名本科生在NSF资助的本科生研究体验计划下的暑期实习期间接受修订分类学方面的培训，以教育未来的科学家识别、描述和说明物种的方法并发表结果。由美国国家科学基金会资助的组装真蝇生命树的广泛研究项目将直接受益于拟议中的阿西里科进化关系研究。

The study of biological diversity has immense scientific and social value, especially today as biodiversity is under serious threat. This dissertation project deals with the investigation of a group of insects that, with approximately 7,000 described species world-wide, is one of the most species-rich families of true flies. Robber flies (Asilidae) are easily recognized and play an important role as insect predators. Although many scientific publications deal with these flies, evolutionary relationships of the species remain obscure. This study focuses on species of the subfamily Leptogastrinae, currently known from 462 species. This group is distinct due to peculiar morphological characteristics associated with a narrow body that are most probably adaptations to a life among grasses. Many other robber-fly species inhabit prairies and grasslands as well, but lack such a distinctive suite of similar morphological features. This project enhances the knowledge about robber flies by (1) presenting well-corroborated hypotheses of the evolutionary relationships of species of robber flies, (2) providing species descriptions and identification keys for species of the subfamily Leptogastrinae, and (3) analyzing the distribution and species richness of species of Leptogastrinae with respect to biodiversity hotspots sensu Conservation International. The findings will allow a discussion of character evolution with respect to habitat preferences of all robber flies, emphasizing grass-inhabiting species and comparing them to species of Leptogastrinae using both morphological characters of the adult flies and DNA sequences. Fieldwork is conducted in South east Asia in order to collect species of robber flies for the analyses, as this region hosts the least-known and sampled fauna. Two major natural history museums housing specimens of Asilidae from South east Asia - London, UK, and Amsterdam, The Netherlands - are visited to examine historical specimens of outstanding importance for identification of freshly collected material.Among many target groups used for studies addressing the biodiversity crisis, insects are always under represented. This dissertation project incorporates one of the most species-rich fly groups into analyses of biological diversity. The dissemination of scientific knowledge to all parts of the world is of immense importance. The species descriptions and identification keys assembled in this project are being published in required printed format in scientific journals as well as on the world wide web as integrative biodiversity databases, therefore making this knowledge available for world-wide audiences including entomologists and conservation biologists. An undergraduate student is trained in revisionary taxonomy during a summer internship under the NSF-funded Research Experience for Undergraduates program in order to educate a future scientist in methods of identifying, describing, and illustrating species and publishing the results. The extensive NSF-funded research project Assembling the Tree of Life - True Flies will directly benefit from the proposed study of the evolutionary relationships of Asilidae.