Evolution of Life Cycles and Host Associations and the Historical Biogeography of Aphids (Subfamily Aphidinae)

蚜虫是一种以植物汁液为唯一食物来源的昆虫。 由于它们的进食模式，蚜虫具有定居的生活方式，并且经常建立非常大的种群。 蚜虫亚科中的许多蚜虫专门以重要的农作物和园艺物种的植物宿主为食（例如，许多粮食作物和果树）。 因此，几种蚜虫是重要的农业害虫，有些是毁灭性的。 一些物种也进化出复杂的生命周期，在几个克隆世代中，在不相关的植物宿主之间（例如，在果树和谷物之间）进行专性的季节性迁移。 蚜虫亚科在北方半球的物种也异常丰富，2500种蚜虫中只有~1%原产于南半球。 几个引人注目的问题，生物多样性，地理学，和宿主植物的进化，在这组仍然没有答案，但是，因为组成物种之间的关系，这可以用来解决这些问题，没有得到很好的理解。 该项目旨在启动蚜虫亚科蚜虫之间关系的研究，以回答以下问题：尽管它们在北方半球具有高度生物多样性，但蚜虫亚科是否起源于南半球？ 随着时间的推移，寄主植物的关系是如何变化的，这些变化又是如何影响物种多样性的？ 复杂的生活史在蚜虫亚科的历史上有多次起源吗？ 我们将从外部形态特征和基因序列收集数据，以重建蚜虫亚科物种之间的关系。该项目将支持一名研究生一年，并将在美国，加拿大，新西兰，中国，阿根廷和欧洲的科学家之间建立国际合作。 对蚜虫形态学的深入了解可能有助于未来的分类方案。 对蚜虫关系的进一步了解也可能有助于未来的生物防治工作，为选择适当的生物防治剂提供信息。

Aphids are insects that tap plant sap as a sole food source. As a consequence of their feeding mode, aphids have sedentary life styles and often build up very large populations. Many aphids in the lineage Aphidinae have specialized in feeding on plant hosts that are important agricultural crops and horticultural species (e.g., many grain crops and fruit trees). Thus, several Aphidinae constitute significant agricultural pests, some quite devastating. Some species also have evolved complicated life cycles that incorporate obligate, seasonal migrations between unrelated plant hosts (for example, between a fruit tree and a grain) over several clonal generations. Aphidinae are also exceptionally species-rich in the northern hemisphere, with only ~1% of the 2500 species native to the southern hemisphere. Several compelling questions concerning the biodiversity, biogeography, and host-plant evolution in this group remain unanswered, however, because relationships among the component species-which could be used to address these questions-are not well understood. This project aims to initiate the study of relationships among Aphidinae aphids, in order to answer questions such as: despite their high biodiversity in the northern hemisphere, did Aphidinae originate in the southern hemisphere? How have host-plant relationships changed through time, and how have these shifts impacted species diversifications? Have complicated life cycles originated multiple times in Aphidinae history? We will collect data from external morphological features and from gene sequences to reconstruct relationships among Aphidinae species. This project will support a graduate student for one year, and will build international collaborations between scientists in the U.S, Canada, New Zealand, China, Argentina, and Europe. Increased insights into morphology of aphids may help in future classification schemes. An improved understanding of Aphidinae relationships may also assist with future biocontrol efforts, informing the selection of appropriate biocontrol agents.