Collaborative Research: Molecular Systematics of Drosophila Repleta Group Species

9527950 DeSalle昆虫群体使用的寄主植物的范围可以很宽也可以很窄，包括寄主植物对单一寄主的专一性或限制。由于占所有动物物种绝大多数的大多数昆虫在其生命周期的某一部分利用植物作为食物或繁殖的场所，了解昆虫成为宿主专家或多面手的原因是很重要的。寄主的使用模式可能对解释昆虫种群的多样性很重要。寄主植物的特定方面可能会限制或增加昆虫物种可以使用的寄主数量。在很长的时间间隔内，这可能会产生具有共同寄主亲缘关系的相关昆虫物种群。该奖项支持的研究项目将利用DNA序列数据相似性模式来研究毛果蝇物种复合体(昆虫纲：双翅目：果蝇科)中40多个物种之间的遗传关联程度。确定的物种关系模式将与这些物种在自然界中的宿主使用情况进行比较。这个复合体中的两个物种簇，每个有三个物种，将被更详细地研究，以寻找DNA序列数据中种群水平变化的证据。这组研究中的果蝇以仙人掌为食，其幼虫以仙人掌为寄主。一些以仙人掌属为食的物种发生了明显的寄主转移，仙人掌属的成员很容易通过桨状部分被识别出来，而其他仙人掌的生长形式是柱状或桶状的。了解果蝇物种之间的关系将有助于确定仙人掌类型之间发生这种转变的次数。该奖项将提供一组专门饲养苍蝇的仙人掌的生物多样性和寄主植物协会的信息。这项研究为了解寄主转移和害虫起源提供了重要的模式系统，对开发L防治害虫的非化学手段具有一定的参考价值。***

9527950 DeSalle The range of host plants used by groups of insects can be broad or very narrow, including host plant specificity or restriction to a single host. Since most insects, which constitute the vast majority of all animal species, use plants during some part of their life cycles for food or as a place to reproduce, it is important to understand the causes for insects to be host specialists or generalists. Patterns of host use may be important in explaining the diversification of insect groups. Particular aspects of host plants may either limit or increase the number of hosts an insect species can use. Over long time intervals, this may give rise to related groups of insect species that share host affinities. The research project supported by this award will use patterns of DNA sequence data similarities to study the degree of genetic relatedness among a group of over 40 species in the Drosophila mulleri species complex (Insecta: Diptera: Drosophilidae). The pattern of species relationships determined will be compared to the host use of these species in nature. Two clusters of species in this complex, each with three species, will be studied in greater detail for evidence of population level variation in DNA sequence data. The fruit flies in this study group breed on cacti and their larvae feed on cactus host plants. There has been an apparent host shift with some species feeding on the cactus genus Opuntia, whose members are easily recognized by paddle shaped parts, to other cacti whose growth form is columnar or barrel shaped. Knowledge of relationships among the Drosophila species will allow determination of the number of times that this shift between cactus types has occurred. %%% This award will provide information on the biodiversity and host plant associations in a group of specialized cactus feeding flies. This research represents an important model system for understanding host shifts and the origin of insect pests that may be of value in developing non-chemica l means of controlling pests. ***