Funk, D.H., and B.W. Sweeney. 1990. Transactions of the American Entomological Society 116(3):727–751.
The systematic relationships and genetic variation among five species of taeniopterygid stoneflies (Taeniopteryx maura, T. burksi, T. nivalis, T. parvula and Strophopteryx fasciata) were studied electrophoretically. All study specimens were reared imagos collected as larvae from streams and rivers in Pennsylvania, USA. Activity was detected for 30 of 46 enzyme systems screened, but only 23 of the 30 (representing 28 presumptive gene loci) could be reliably scored. Polymorphic loci ranged from 16 to 42% of the total, with expected heterozygosities ranging from 8 to 16% depending on the species. Three loci appear to be sex-linked: malate dehydrogenase-1 for S. fasciata, and phosphogluconate dehydrogenase and pyruvate kinase for the Taeniopteryx species. Phylogenetic relationships derived from electrophoretic data were generally similar to accepted morphologically based hypotheses. Taeniopteryx burksi, T. maura, and T. nivalis form a closely related species group, with T. parvula representing a distinct lineage within Taeniopteryx. Strophopteryx fasciata appears to be distantly related to Taeniopteryx. The most closely related species pair, T. maura and T. burksi, exibited distinct differences in allele frequencies at eight loci, six of which were diagnostic. No evidence of hybridization was found, even though both species coexist and emerge synchronously at all sampling localities. Eight males which had very small femoral spurs (thereby “keying” morphologically to T. burksi) were determined biochemically to be T. maura. This suggests that, at least in our study area, males with any trace of a femoral spur are T. maura and only males without spurs should be considered T. burksi. Slight differences in allele frequencies were detected between adults representing two larval color morphs of T. nivalis, but these were not considered to be taxonomically important. Enzyme electrophoresis was found to be a very sensitive method for determining species boundaries in taeniopterygids.