Using DNA Sequences to Determine the Geographic Origins of Agriculturally Important Invasive Leafmining Flies

The increased global movement of people and goods has resulted in introduction of agricultural pests into new areas. Understanding the patterns and processes of colonization by introduced species is crucial in planning interventions and management strategies. However, determining the origin and colonization patterns of invasive species can be difficult. Molecular markers such as DNA sequence data can help determine the history of movement by an invasive species. Liriomyza huidobrensis is a leafmining fly that feeds within leaf tissue of crops, including potatoes and beans. Although native to South America, it has spread throughout the world and is of great concern. Understanding the origin and pathways of dispersion can determine the means of spread, possibly leading to the development of interception and control programs. We analyzed 2125 base pairs of mitochondrial cytochrome oxidase genes (COI & COII) in a phylogeographic approach to uncover distribution of genetic variation of L. huidobrensis. Our phylogeographic analysis of mitochondrial COI and COII found substantial geographic structure within L. huidobrensis in its native range, but almost none within and between invasive populations around the world.The data suggest that the invasive populations trace to the Peru/Ecuador region. We are collecting additional data to test this hypothesis.