Tackling the species problem: theory and application in plant -feeding insects

生物多样性和进化成功通常以物种数量来衡量，但对于许多生物体群体来说，很难确定一个物种在哪里结束，另一个物种从哪里开始。这种不确定性源于最初创造这些物种的进化过程。该研究计划将解决“物种问题”的理论和实践方面的问题，研究创造物种的过程并开发限制和描述它们的方法。******昆虫占地球上所有已描述生命的一半以上。与其他昆虫一样，以汁液为食，寄生专门的蚜虫，随着被子植物的辐射而多样化。然而，最多样化的蚜虫群体之一是个例外，它已从被子植物转向针叶树寄主。虽然该组的大多数物种以其寄主的木质部分为食，但其他四个组的物种仅以松针为食。这些针食谱系共享相同的生态位，代表了宿主和生态位专业化和多样化的进化复制。这些独立的谱系是否以类似的方式多样化？每个群体所经历的相似的环境压力是否导致了进化趋同，或者每个谱系都以自己的方式进化？回答这些问题将揭示导致昆虫令人难以置信的多样化的过程。该研究的第一个目标是利用 DNA 序列和生态数据来比较植物宿主、细菌共生体和地理因素对这些蚜虫物种形成的相对重要性。******在蚜虫中，寄主植物关联通常用于发现新物种和识别它们，这是一个有问题的循环，因为已知寄主植物会影响蚜虫的发育及其外观。研究的第二个目标是利用现代遗传学方法彻底划定物种之间的概念界限。将对不同的群体进行检查和比较，看看是否可以将相同的方法应用于所有蚜虫。********对于第三个目标，该项目将确保我们检查的物种在网上得到正确、完整的描述和编目。新颖的计算机方法将加快描述过程，包括出版三维数字成像的博物馆标本。它们将形成一个虚拟参考资料库，为研究人员和昆虫鉴定人员提供前所未有的研究工具。****** 蚜虫是对农业最具经济破坏性的害虫之一。人们花费了大量资源试图了解不同物种的生物学并区分害虫和非害虫物种。拟议的项目将极大地提高我们了解蚜虫物种的能力，并为一般物种，特别是昆虫物种的性质带来新的认识。

Biological diversity and evolutionary success are often measured in terms of species numbers, but for many groups of organisms, it is difficult to determine where one species ends and another begins. This uncertainty has its origins in the evolutionary processes that create those species in the first place. The research programme will address both theoretical and practical aspects of the “species problem”, examining the processes that create species and developing methods to circumscribe and describe them.******Insects account for more than half of all described life on Earth. As with other insects, sap-feeding, host specialist aphids, diversified with the radiation of angiosperm plants. One of the most diverse aphid groups is an exception, however, having switched from angiosperm onto conifer hosts. Whereas most species of this group feed on woody parts of their hosts, those of four other groups feed exclusively on pine needles. Sharing the same ecological niche, these needle-feeding lineages represent evolutionary replicates of host- and niche-specialization and diversification. Did these independent lineages diversify in similar ways? Did the similar environmental pressures experienced by each group lead to evolutionary convergence, or did each lineage evolve in its own way? Answering these questions will shed light on the processes that led to the incredible diversification of the insects. The first objective of the research is to use DNA sequence and ecological data to compare the relative importance of plant host, bacterial symbiont, and geographic factors to the speciation of these aphids.******In aphids, host plant association is often used both to discover new species and to identify them, a problematic circularity because host plants are known to affect aphid development and what they look like. The second objective of the research is to use modern genetic methods to thoroughly delimit the conceptual boundaries between species. Different groups will be examined and compared to see if the same methods can be applied across all aphids.******For the third objective, the project will make sure the species we examine are properly and fully described and catalogued online. Novel computer methods will speed up the descriptive process, including the publication of museum specimens digitally imaged in three dimensions. They will form a virtual reference collection, providing researchers and insect identifiers an unprecedented research tool.******Aphids are among the most economically devastating pests of agriculture. Considerable resources are expended trying to understand the biology of different species and to discriminate pest and non-pest species. The proposed project will dramatically accelerate our capacity to understand aphid species and bring new understanding to the nature of species in general and insect species in particular.