Systematics, diversity & speciation of Lepidoptera

云杉小球蛾是北美针叶林的主要食叶害虫，尽管几十年来一直在努力控制它们的种群数量，但它们的定期暴发影响着森林结构，并造成了很大的经济损失。东半球燕尾种类的蝴蝶也受到了很大的关注，尽管主要是因为它们很大，对博物学家来说在视觉上很有吸引力。尽管进行了多年的研究，但这两类鳞翅目昆虫都有一个共同的事实，即我们仍然不知道它们包含多少物种，也不知道如何区分它们。这可能是因为这些物种在一些地区正在分化，在另一些地区则在融合。我们想知道为什么会发生这种情况，因为这将使我们深入了解物种形成是如何发生的。换句话说，一个物种如何以及为什么可以变成两个物种？新物种有时会由以前不同物种之间的杂交而形成吗？我的研究生将追踪云杉芽孢虫蛾及其近亲在Choristoneura属的起源和进化，背景是它们与它们赖以生存的树木的联系，它们用于交配的引诱剂，以及它们用来在北半球和非洲传播的大陆扩散路线。他们还将研究当地景观结构在多大程度上影响北美燕尾蝴蝶物种之间的交配和基因流动。在许多样本中有效地测量大量基因的新技术使现在成为开展这类研究的令人兴奋的时机。我们终于可以问，在种群的分化或合并中涉及到哪些类型的基因，以及多少基因。更早的研究表明，与物种差异相关的基因不成比例地存在于性染色体上，就蝴蝶和飞蛾而言，性染色体仅占其总基因组的3%左右。如果这是真的，那么如果我们想要有效地诊断和了解我们周围的飞蛾、蝴蝶和生命的多样性，也许我们应该首先看看这些染色体上的基因。

Spruce budworm moths are major defoliators of conifer forests in North America, influencing forest structure by their regular outbreaks and causing much economic damage despite many decades of effort to manage their population numbers. Butterflies of the Old World Swallowtail species group have received much attention as well, although mainly because they are large and visually attractive to naturalists. Both groups of Lepidoptera share the fact that we still don't know how many species they contain and how to tell them apart, in spite of years of study. This may be because these species are in the process of diverging in some areas but merging in others. We would like to know why this might be happening, since this would give us insight into how speciation occurs. In other words how and why can one species can turn into two species? And can new species sometimes form from hybridization between previously distinct species? My graduate students will trace the origin and evolution of spruce budworm moths and their relatives in the genus Choristoneura in the context of their associations with the trees they feed on, the attractants they use for mating, and the continental dispersal routes that they have used to spread across the Northern Hemisphere and through Africa. They will also study the extent to which local landscape structure influences mating and gene flow between the species of swallowtail butterflies across North America. New technologies for efficiently surveying large numbers of genes in many specimens have made this an exciting time to carry out this kind of study. We can finally ask what kinds of genes, and how many, are implicated in divergences or merging of populations. Older work has suggested that the genes associated with species differences are disproportionately found on the sex chromosomes which, in the case of butterflies and moths, make up only about 3% of their total genome. If that is true, then perhaps we should be looking first at the genes on these chromosomes if we want to effectively diagnose and understand the diversity of moths, butterflies, and life around us.