2007 EPT Blitz and Barcoding for GSMNP
2007 EPT Blitz and Barcoding for GSMNP
Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies), or “EPT”, are commonly encountered aquatic insects and are widely used in freshwater biomonitoring. However, the difficulties in species-level identification, especially of immature stages, have hindered their implementation. DNA barcoding can improve resolution on taxonomic identification, enable confident association of larval and adult stages, and discriminate cryptic species. A COI barcode reference library established from expertly identified specimens is a prerequisite for applying DNA barcoding to the identification of aquatic insects. The GSMNP has highly diversified EPT fauna and is an ideal region for a model study of DNA barcoding of EPTs. A new EPT blitz is proposed to survey a broader area of the Park (especially central, southern, and eastern portions) with an emphasis on authoritatively identified adults. This survey will discover new Park species, discover new species for science, and establish a COI barcode reference library for all EPT species collected during the survey.
A bio-blitz survey of the Ephemeroptera, Plecoptera, and Trichoptera (EPTs) of the Great Smoky Mountains National Park, was conducted in the spring of 2007, with an emphasis on establishing a DNA barcode reference library for the three orders. Fourty six Ephemeroptera, fourty three Plecoptera, and eighty four Trichoptera species were collected during the three-day survey, representing 38.3%, 38.7%, and 36.4%, respectively, of the species known to occur in the Park. Four or five new park records were added in this short bio-blitz: Eurylophella bicolor, Rhithrogena anomala, Isoperla namata, I. signata (uncertain), and Homoplectra flinti. Additionally, 30 species showed deep genetic divergence within species boundaries defined by morphology. Some of these distinct genetic clusters are expected to represent cryptic species, many of which are likely to be new to science. While the routine barcoding primer sets were effective in amplifying COI in the EPTs, sequencing success rates were biased in certain taxon groups, which was likely the result of nucleotide variations in the primer regions. In general, COI sequences were effective in tracing species boundaries in EPTs. The observed overlapping species boundaries and deep intraspecific divergence in COI in certain taxa suggested the need for reconsideration of the current species concepts in a number of EPT species. Finally, our result showed that DNA barcoding provided a finer resolution in specimen identification in these groups than morphology alone.
