Flower visitation on two wings: the impact of Diptera as pollinators

苍蝇（双翅目）是地球上最多样化的动物群体之一，有超过16万种被描述的物种。近年来，花蝇在传粉中的重要作用得到了广泛的认识。它们访问了全球50%以上的农作物，每年的经济价值估计为3000亿美元，它们还访问了欧洲70%以上的动物授粉的野花物种。食蚜科是一个大的蝇科，在世界范围内大约有6300种，而在北美大陆已知的只有800多种。由于最近的一些出版物，该群体的多样化在亚家族水平上得到了相对较好的理解，但重要的问题仍然存在-特别是关于亚家族Eristalinae，一个被广泛理解为不相关谱系的集合的群体。我的研究计划有三个长期目标：1)通过系统发育分析和分类修订来了解世界范围内花蝇的进化和多样性；2)通过发布用户友好的识别工具，方便其他研究人员获取花蝇物种概念；3)确定蝇类特别是花蝇对自然生态系统和农业生态系统传粉的影响。我的研究团队将在未来五年内通过关注北美花蝇的多样性、进化和生态学来实现这些目标。我们对北美花蝇的了解有几个主要的局限性，阻碍了我们在生态学研究中使用这些群体的能力。我们还迫切需要了解北美花蝇的多样性，以便绘制植物与传粉者的关系，这种关系是北极等脆弱和快速变化的栖息地的基础。为了满足这些迫切的需求，我的短期目标是：1)利用系统基因组学方法追踪花蝇部落Rhingiini的进化，然后利用这些知识来识别物种的单系群；2)以目的1所划分的单系类群为指导，对种类丰富的花蝇属Cheilosia进行分类研究，完善物种概念；3)通过花粉元条形码绘制加拿大北极地区花和苍蝇的植物传粉者网络，重点研究了Cheilosia的物种。目前对种类丰富的属（如Cheilosia）的分类缺乏明确，极大地限制了我们研究北美花蝇传粉动力学的能力。鉴于苍蝇是加拿大北极等寒冷气候环境中的主要传粉者，我们有必要揭示这些昆虫的分类和特定的生态服务。北极传粉网络的具体知识将提供对关键植物和昆虫物种的更好理解。有了这些知识的支持，我们将能够更好地预测这些生态系统将如何被日益变暖的气候改变或破坏。

Flies (Diptera) are among the most diverse groups of animals on the planet, with over 160,000 described species. In particular, flower flies (Syrphidae) have been recognized in recent years for their important role in pollination. Visiting over 50% of global crop plants, their economic value has been estimated at $300 billion USD per year, and they have also been recorded visiting over 70% of animal-pollinated wildflower species in Europe. Syrphidae is a large family of flies, with about 6,300 species described worldwide, and just over 800 species known to occur in continental North America. The group's diversification is relatively well understood at the sub-familial level, thanks to several recent publications, but important questions remain-especially concerning the subfamily Eristalinae, a group widely understood as a collection of unrelated lineages. My research program has three long-term goals: 1) To understand the evolution and diversity of flower flies worldwide through phylogenetic analyses and taxonomic revisions; 2) To facilitate access to flower fly species concepts for other researchers through the publication of user-friendly identification tools; 3) To determine the impact of fly, especially flower fly, pollination in natural and agricultural ecosystems. My research team will work toward these goals over the next five years through a focus on the diversity, evolution, and ecology of North American flower flies. Our understanding of North American flower flies has several major limitations, hindering our ability to use these groups in ecological studies. There is also a critical need to understand our North American flower fly diversity in order to map the plant-pollinator relationships that underpin vulnerable and rapidly changing habitats such as the Arctic. To meet these pressing needs, my short-term objectives are: 1) Trace the evolution of the flower fly tribe Rhingiini using phylogenomic methods, then use this knowledge to recognize monophyletic groups of species; 2) Guided by the monophyletic groups delimited by Objective 1, investigate the taxonomy of the species-rich flower fly genus Cheilosia to improve species concepts; and 3) Map plant-pollinator networks of flowers and flies in the Canadian Arctic through pollen metabarcoding, with a focus on species of Cheilosia. The current lack of taxonomic clarity regarding species-rich genera such as Cheilosia greatly limits our ability to study the pollination dynamics of flower flies in North America. Given that flies are the dominant pollinator in cold-weather environments such as the Canadian Arctic, it behooves us to uncover the taxonomy and specific ecological services contributed by these insects. Specific knowledge of Arctic pollination networks will provide a better understanding of keystone plant and insect species. Bolstered by this knowledge, we will be better able to predict how these ecosystems will be altered or disrupted by the increasingly warm climate.