Molecular comparison of Quebec and Newfoundland populations of the blackfly, Simulium vittatum, species complex

Specific haplotypes at five positions in the COI and COII mitochondrial genes allowed a partial differentiation of Simulium vittatum Zetterstedt (Diptera: Simuliidae) populations from Quebec-Ontario and Newfoundland, respectively. This geographical signature was superimposed on about 40 other polymorphic sites such that sequence divergence alone did not enable a clear-cut distinction between the two populations. Together with the sporadic occurrence of haplotypes intermediate to the Newfoundland and Quebec-Ontario consensus, this suggested that one peculiar sequence among many found in populations from the North American landmass predominates in Newfoundland as a result of a founder effect. The internal transcribed spacer (ITS1) sequence from the nuclear rDNA transcription unit was no more able to resolve populations along geographical lines than the COI/COII criteria.