Illinois Natural History Survey (INHS) scientist Ed DeWalt recently answered a few questions about his career as an aquatic entomologist.
Tell us a little bit about yourself and your research.
I am an aquatic entomologist studying the taxonomy, phylogeny, and conservation of stoneflies (Plecoptera). I have also published on mayflies (Ephemeroptera) and caddisflies (Trichoptera). Taken together, these are known as EPT species and are useful indicators of water quality the world over. I also host a website, Plecoptera Species File, that provides access to a global list of species, a single classification, literature, images, and specimen data.
What drew you to your particular area of study, particularly stoneflies?
When I began graduate work I used an identification key to stoneflies of North America to identify specimens from my ecological work. I was most fascinated by the stoneflies. I wrote the author (Kenneth W. Stewart at the University of North Texas) to see if he would take me on as a Ph.D. student and he said yes. He and his students instilled in me love of the insects themselves: their phylogeny, description of new species and revisions of groups, life histories of species and assemblages, all basic information that often is lost from ecological work but entirely necessary for constructing hypothesis-driven work.
What do you love about being an aquatic entomologist?
I love fieldwork! Discovering new species is great fun. I love to go to a river and be surprised by what lives there. An ultraviolet light trap along a large river that yields multiple species of stoneflies really is exciting for me. I also love museum work. Finding a large number of pinned stoneflies at a regional museum collected from the early part of the 20th century is very exciting since these specimens tell me what occurred in a river before we messed it up!
What has been one of the most exciting moments of your career?
I think it was the publication of a phylogeographic paper on the post-glacial dispersion and glacial refugia of a stonefly called Acroneuria frisoni. This species had been lost from much of the glaciated Midwest and there was interest in the reintroduction of it to some parts of Illinois where water quality had improved. However, I wanted to know a lot about the species because I did not want to reintroduce a population that did not represent the orginal genetic structure of the historical population.
My graduate students scoured the Midwest from Arkansas to Wisconsin and into southeast Pennsylvania to understand the genetic structure across the entire range of the species. We found the first populations in Wisconsin and discovered that there were two refugia (Ozark and W Appalachian Mts.). We also found that some Ozark haplotypes bled into Illinois along the western Shawnee Hills and that nearly all of the recolonization of the Midwest occurred from Tennessee and Kentucky, not from the Ozarks. The Wisconsin haplotypes matched the southern Indiana ones. Southern Indiana was our source for eastern Illinois reintroductions.
In the summer of 2009, we released over 11,000 eggs to the Middle Fork of the Vermilion River. This attempt to bring back the species to Illinois failed, maybe due to high water, but we will try again to regain some of the state's biological diversity.