Submitted to: Annals of the Entomological Society of America
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/7/2004
Publication Date: 2/12/2005
Citation: Scheffer, S.J., Lewis, M.L. 2004. Phylogeography of the liriomyza trifolii - l. sativae leafminer complex (diptera: agromyzidae): cryptic species, host races, and invasive populations. Annals of the Entomological Society of America 98:181-186 Interpretive Summary: Leafmining flies are important pests of many vegetable and flower crops including peas, beans, melons, onions, tomatoes, potatoes, celery, garlic, lettuce, chrysanthemums, and carnations. During outbreaks, these insects can cause severe damage to these crops, resulting in substantial economic losses. Originally known only from the Americas, these flies have been introduced into many locations around the world. This research investigated the evolutionary relationships of these vegetable leafminers sampled from around the world using DNA sequence data. Results indicate that both leafminer species are complexes comprised of cryptic species. This may explain some of the differences that have been observed in pest status and levels of insecticide resistance between populations from different locations. This work also has implication for quarantine regulations. This research is of interest to researchers, pest management specialists, and quarantine officials working with leafminers.
Technical Abstract: The leafmining flies Liriomyza sativae and L. trifolii are important pests of vegetable and cut-flower crops. In recent decades, these flies have become invasive and have been spread from the Americas to the rest of the world. Despite substantial losses caused by these flies, the systematics of these flies has remained poorly understood due to their small size and morphological homogeneity. Phylogeographic analysis of mitochondrial cytochrome oxidase I sequence variation indicates that both L. sativae and L. trifolii harbor multiple distinct phylogenetic lineages indicative of the presence of cryptic species. There is also evidence of a recently derived, highly specialized pepper host race within L. trifolii. Only some phylogenetic lineages were present in introduced populations, suggesting that lineages differ in their probability of invasion into new areas. Total mitochondrial variation exhibited by introduced populations was therefore considerably reduced compared to that observed within native ranges. When diversity comparisons were limited to invasive lineages in native ranges versus invasive lineages in introduced populations, no dramatic differences were found. This suggests that the reduced variation observed in introduced populations is not due to bottlenecks associated with invasion, but predates invasions and possibly reflects bottlenecks associated with colonization of the agricultural environment or selective events within pest populations. The pattern of reduced mitochondrial variation was most pronounced in the invasive L. trifolii, which has a history of recent and rapid evolution of insecticide resistance.