Abai, MR

6th International Congress of DipterologyKey Words: Simuliidae, Diptera predators∗∗∗∗∗∗∗∗∗∗Comparative phylogeography of the black flies (Diptera:Simuliidae) in Thailand based on mitochondrial DNAsequencesPramual, P. (1), C. Kuvangkadilok (1), C. Walton (2) & V. Baimai (1)(1) Department of Biology, Faculty of Science, Mahidol University, Bangkok, 10400Thailand(2) Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M139PT, UKPopulation genetic structures of three black fly species, namely, Simuliumtani, S. nakhonense and S. quinquestriatum, were determined using 720base pairs of the cytochrome oxidase I (COI) gene of mitochondrial DNA.All of these black flies had similar patterns of population genetic structureand diversity. Populations from the northern region have greater diversityand are highly structured within this region as well as being geneticallydifferentiated from populations in other regions. Both geographical (e.g.mountain ranges) and ecological conditions of the habitat seem to beimportant factors in limiting gene flow and allowing populations togenetically differentiate. The greater diversity and higher genetic structureof the northern populations is likely due to the longer history ofpopulations in this region. In contrast, populations from the south werecolonized recently from a subset of the haplotypes from the lower north orcentral regions approximately 100,000 to 200,000 years ago followed bypopulation expansion. The absence of genetic structure in the southernpopulations is most likely due to the recent history of populations in thisregion rather than a high level of gene flow between populations. Thesimilar pattern of genetic structure and diversity among geographically co-198