Abstract
Rhyacophila lobifera Betten, 1934 has been previously documented in the upper Midwest states of Ohio, Indiana, and Illinois, and the province of Ontario. Here we report on the diversity of this species in the Rouge and Huron River watersheds using DNA barcode-verified identifications to confirm the first known Michigan record of this species, with collection from the lower Rouge River in 2003 and again in 2008. Since first detection, we document that the range of R. lobifera in the Rouge River watershed has expanded to include at least one additional site on the Lower Branch and five sites on the Middle Branch (Johnson Creek), as well three sites in the neighboring Huron River watershed. Our sequence analysis of the mitochondrial COI barcode gene region suggests a fine scale population structure in these watersheds, with haplotype partitioning congruent with proposed dispersal patterns based on first records at each site. Ranking as a 4 on the Hilsenhoff's biotic index—an intermediate level of water quality tolerance, discovery of R. lobifera in an urbanized southeast Michigan watershed is not unexpected, but population genetic patterns lend insight into its recent range expansion.