Mitochondrial Phylogeography of the Vegetable Pest Liriomyza trifolii (Diptera: Agromyzidae): Diverged Clades and Invasive Populations

The leafmining ßyLiriomyza trifolii (Burgess) (Diptera: Agromyzidae) is an important pest of vegetable and cut-ßower crops. In recent decades, this species has become invasive, spreading from the Americas to the rest of the world. Despite substantial losses caused by Liriomyza leafminers, the systematics of these ßies has remained poorly understood because of their small size and morphological homogeneity. Previous molecular research on other polyphagous Liriomyza pests has suggested that cryptic species may be present. Here, we use mitochondrial cytochrome oxidase I sequence variation to investigate phylogeographic structurewithinL. trifolii. Our results indicate that L. trifolii harbors distinct phylogenetic clades, suggesting the presence of cryptic species. There is also evidence of a recently derived, highly specialized pepper (Capsicum spp., Solanaceae)-feeding population within L. trifolii that may represent a host race or even a distinct species. Introduced populations from various locations contained a highly restricted subset of the mitochondrial variation present within L. trifolii, suggesting one or more bottlenecks during colonization.