This proposal addresses one of the central problems in the study of coevolution: how interactions between species evolve during population differentiation and speciation. Much of the diversity of insect species has arisen through the differentiation of insect populations onto different plant species. This study focuses on one of the classically cited cases of coevolution between insects and plants in which pollinators of the plants have evolved as seed parasites. Specifically, the study will analyze the systematics of the Prodoxidae (Lepidoptera) and the phylogeny of host associations and interactions between these moths and their host plants. These moths incluce the yucca moths and related genera, and they have evolved species onto a wide variety of plants over time. The study will take advantage of recent findings on host associations and mutualism in Greya spp: some of these species are exclusively seed parasites, whereas other species appear to be the primary pollinators of their hosts. Many of the same behaviors seen in Greya also occur in the closely related genera that are pollinators of yuccas. The study has three specific objectives. In Objective 1 the evolutionary history of the Prodoxidae will be inferred using sequence analyses of mtDNA. Objective 2 is to study the systematic relationships within Greya, the pattern of association with plant taxa that has evolved within this genus, and the origins of the morphologies and behaviors important to the evolution of mutualism. Finally, Objective 3 is to study differentiation in the interactions between Greya politella and its host plants. Greya politella is the widespread species in the genus, and the outcomes of interactions between these moths and their host plants appear to vary among populations. Consequently, study of the systematics of Greya, its relationship to other prodoxid genera, and the distribution of behaviors involved in mutualism will provide an opportunity to study the evolutionary processes that shape the outcomes of coevolution. These results will provide a more solid empirical basis for evaluating current theories on the mechanisms of coevolutionary change.
