Genetic Variation in North American Black Flies in the Subgenus \u3ci\u3ePsilopelmia\u3c/i\u3e (\u3ci\u3eSimulium\u3c/i\u3e: Diptera: Simuliidae)

Resolution of the genetic heterogeneity of closely related insect species depends on the selection of reliable genetic markers derived from representative specimens. We report the results of a survey of genetic variability in nine species of black flies in the subgenus Psilopelmia Enderlein. Three regions of the mitochondrial genome and an amplicon including the internal transcribed spacer 1 of the nuclear ribosomal RNA gene cluster (ITS1) were amplified using the polymerase chain reaction (PCR), and the amplicons were examined for intraspecific and interspecific polymorphisms. Six of the seven Psilopelmia species that yielded PCR products in the ITS1 PCR reaction were found to generate products that were indistinguishable on the basis of size. Similarly, little interspecific variation was noted in the 16S rRNA amplicon among nine species of Psilopelmia assayed by heteroduplex analysis. In contrast, the remaining regions of the mitochondrial genome exhibited both intra- and inter-specific variation when analyzed by heteroduplex analysis. Information collected from the five amplicons could be employed to develop a classification scheme capable of distinguishing the nine species of Psilopelmia examined