Grant: Discovery Grants Program - Individual

Butterflies and moths form one of the great groups of herbivores that comprise the diversity of life on our planet. They are important not only because they compete with us for food and fiber, but also because their beauty captures our imagination. Caterpillars of spruce budworm moths are major defoliators of conifer forests in North America, influencing forest structure by their regular outbreaks and causing substantial 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 turn into two species? And can new species sometimes form by hybridization between previously distinct species? We will investigate the origin and evolution of species of spruce budworm moths and their relatives to understand how they have interacted with their environment over time to diversify across the Northern Hemisphere and into the Old World. The classification and delimitation of these moths is important in allowing us to efficiently focus our management of the forests that they affect. We will also study the extent to which local landscape structure influences mating and gene flow between the species of swallowtail butterflies across North America. We are well positioned to take advantage of rapidly advancing technologies that allow us to more efficiently survey genetic variation within and between populations. We are at the brink of being able to determine what kinds of genes, and how many, are essential for divergences or merging of populations. Our previous work has shown that the genes associated with species differences are mostly found on sex chromosomes that, in the case of butterflies and moths, make up only about 3% of their total genome. If this is true, then looking first at the genes on these chromosomes will allow us to more effectively diagnose and understand the diversity of moths, butterflies, and life around us.