Phylogeny and Dispersal in the Grass-Feeding Delphacid Planthoppers (Insecta: Hemiptera: Delphacidae)

飞蝇科，俗称飞虱，是一个相对较大且分布广泛的植食性昆虫类群。稻飞虱的经济重要性是有据可查的。该科包括至少55种以经济作物为食的物种，并包括世界十大粮食作物中的五种的主要害虫，如水稻、甘蔗、玉米、芋头和谷物。稻飞虱作为害虫的重要性，特别是在水稻上，推动了对其控制的研究。直接饲养和传播各种植物疾病都会造成植物损害，每年可给全世界的农业造成数百万美元的损失。一些稻飞虱类群往往是专门的草食动物(包括谷类作物草)，而另一些类群则以莎草、灯心草和双子叶为食。根据环境线索，草食性稻飞虱若虫发育成短翅型或长翅型。短翅型在有利的条件下繁殖更多的后代，而长翅型在条件不佳时能够分散到新的环境中。尽管飞虱在科学和经济上的重要性已经得到证实，但飞虱群体之间的进化关系基本上是未知的，这有效地限制了对这些昆虫的生物学研究。这项研究的目的是利用解剖学比较和DNA分析的组合证据，基于全球范围内的飞虱科昆虫样本重建这些昆虫科内的进化关系。通过在地理分布和寄主植物关联的背景下确定和解释稻飞虱的进化历史，研究人员将检验他们的假设，即寄主植物向草的转移是高级稻飞虱进化成功(即更大的多样性和范围)的原因。了解本研究产生的稻飞虱进化对于控制已知的稻飞虱作物害虫以及控制未来新的稻飞虱害虫的暴发具有特别重要的意义。这项工作还将为整合对个别稻飞虱物种进行的大量科学研究提供一个框架。研究人员还将开发可在互联网上访问的密钥，以帮助识别稻飞虱物种；这些密钥对研究这些昆虫的科学家以及受这些昆虫影响的农业环境中的工作人员都将具有相当大的价值。此外，通过这项研究进行的尖端进化分析将为其他动植物群体的类似研究提供模式。

The insect family Delphacidae, commonly called planthoppers, is a relatively large and widely distributed group of plant-feeding insects. The economic importance of planthoppers is well documented. The family includes at least 55 species that feed on economic plants and includes major pests of five of the top ten major world food crops, such as rice, sugarcane, maize, taro, and cereals. The importance of planthoppers as pests, particularly on rice, has driven research on their control. Plant damage results both from direct feeding and transmission of various plant diseases capable of causing millions of dollars of damage annually to the worldwide agricultural industry. Some planthopper groups tend to be specialist grass feeders (including cereal crop grasses), whereas other groups feed on sedges, rushes, and dicots. Based on environmental cues, nymphs of grass-feeding planthopper species develop into either short-winged or long-winged forms. Short-winged forms produce more offspring under favorable conditions, while long-winged forms are able to disperse into new environments when conditions are unfavorable. Despite the well-established scientific and economic importance of planthoppers, evolutionary relationships among planthopper groups are essentially unknown, effectively limiting biological studies on these insects. The purpose of this research is to reconstruct, using a combination of evidence taken from anatomical comparison and DNA analysis, the evolutionary relationships within the planthopper family Delphacidae based on a worldwide sample of these insects. By determining and interpreting planthopper evolutionary history in the contexts of geographic distribution and host plant association, the researchers will test their hypothesis that host plant shifts to grasses are responsible for the evolutionary success (i.e., greater diversity and range) of advanced planthoppers.The understanding of planthopper evolution generated by this research will be of particular importance to the control of known planthopper crop pests, as well as for the control of future outbreaks of novel planthopper pests. This work will also provide a framework for integrating the considerable number of scientific studies that have been conducted on individual planthopper species. The researchers will also develop Internet accessible keys to aid in the identification of planthopper species; these keys will be of considerable value to both scientists studying these insects, as well as workers in agriculture environments affected by these insects. Additionally, the cutting-edge evolutionary analyses carried out through this research will serve as a model for similar studies on other plant and animal groups.