Evolution of Host Plant Use by Hawaiian Planthoppers

当生物在新的栖息地定居或入侵时，它们的生物学会以戏剧性的方式发生变化。这个过程被称为适应，在面对新的环境时，这往往是生物有机体成功的关键。当以植物为食的昆虫进入新的栖息地时，可以改变的一种方式是转向以新的和不同类型的植物为食。这种变化的一个明显的例子是在Delphacidae科中一群被称为灰飞虱的以汁液为食的昆虫中。世界上大多数飞燕草都专门以草和莎草(都是单子叶植物)为食。这一组中的飞虱种类包括水稻和玉米等著名害虫。在太平洋的岛屿上定居后，这些昆虫进化成以各种令人惊叹的寄主植物为食，那里的本土草和莎草相对较少。事实上，现在仅在夏威夷，不同种类的稻飞虱就以28个植物科的植物为食，其中大部分是双子叶植物。在其他太平洋群岛上也发现了类似的模式，包括社会群岛和法属波利尼西亚的马克萨斯群岛。这个项目将使用DNA序列中的信息来了解这些昆虫必须改变宿主的模式。此外，这一结果将揭示所谓的昆虫适应性辐射，这些昆虫现在已经与夏威夷和太平洋岛屿上的这些宿主一起多样化。该项目利用了夏威夷等太平洋群岛的地质史提供的历史时间“快照”。作为研究的一部分，一名研究生和一名博士后研究员将接受这类昆虫的生物学和系统学方面的培训，特别是Delphacini部落，这是一个具有重要经济和科学意义的分类学群体。

9981513RoderickWhen organisms colonize or invade new habitats, their biology can change in dramatic ways. This process, called adaptation, is often critical to the success of biological organisms when faced with new environments. One way that plant-feeding insects can change when entering new habitats is to switch to feeding on new and different types of plants. A striking example of this type of change is seen in a group of sap-feeding insects called planthoppers in the family Delphacidae. Most delphacids world-wide are specialized to feed solely on grasses and sedges (both monocots). Planthopper species in this group include notable pests of rice and maize. After colonizing the islands of the Pacific, where there are relatively few native grasses and sedges, these insects have evolved to feed on an amazing variety of host plants. In fact, different species of planthoppers now feed on plants in a total of 28 plant families, mostly dicots, in Hawaii alone. Similar patterns are found on other Pacific archipelagos, including the Society Islands and the Marquesas in French Polynesia.This project will use information from DNA sequences to understand the pattern of changes that must have taken place for these insects to switch hosts. In addition, the results will shed light on the so-called adaptive radiation of insects which have now diversified in concert with these hosts within Hawaii and the insular Pacific. The project takes advantage of the historical temporal "snapshots" provided by the geological history of Pacific archipelagos such as Hawaii. The research also focuses on the diverse, yet little studied, endemic terrestrial fauna of this region.As part of this research, a graduate student and a postdoctoral fellow will be trained in the biology and systematics of this group of insects (the Delphacidae) and in particular, the tribe Delphacini, a taxonomic group of both great economic and scientific importance.