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APSU's Hamilton publishes long-awaited paper on new insect species


          In the eastern highlands of Brazil, near the densely populated city of Rio de Janerio, there exists many streams and rivers where caddisfly larvae thrive and over which the adults swim and mate. The tiny, drab-colored insects are related to moths and butterflies, but rather than having scale-covered wings like their familiar cousins, the wings are covered by small hairs.

            But human expansion and development, in an effort to make room for the region’s millions of people, is threatening the habitats of these insects, and they are in danger of disappearing from the earth without anyone, even scientists, knowing of their existence.

            Twenty-five years ago, a young Ph.D. student at Clemson University named Steven Hamilton tried to remedy this problem.

            “No one had yet discovered them, but a lot of it is no one had ever looked in these places,” he said. “The species just hadn’t been discovered. When it comes to insects and a lot of invertebrate groups, we know of far less than half of the species. This is about the discovery of the biodiversity that’s around us.”

            Hamilton, now a full professor of biology and director of the Austin Peay State University Center of Excellence for Field Biology, identified nine new species of Polycentropus, a genus of caddisflies that formed the basis of his dissertation, a review of the 74 New World species of the genus. He intended to have his findings published in a scholarly journal, but soon after graduating in 1986, he took a job teaching at APSU.

            “It really stalled when I came here,” he said. “Duties and responsibilities here were different. It just laid there. I’d run into people who’d ask how it was going. It was like a nagging ache, almost. Here I was, the world authority for this group, and the product of my several years of work just sat there.

            “The fact is,” Hamilton said, “there was no great pressure to publish the work because there are too few scientists conducting this sort of research. There are more than enough organisms to go around. I didn’t need to worry about someone sniping ‘my’ species. In the caddisflies alone, a relatively small order of insects, there are more than 12,000 species known and new species being discovered and described every year.”

            Last month, Hamilton and his colleague from the University of Minnesota, Dr. Ralph Holzenthal, finally published the results of their two-plus decades of work, “Twenty-four new species of Polycentropus from Brazil,” in the peer-reviewed journal, ZooKeys.

            “It ended up being 24 new species, so the nine new species from my dissertation were like yeast,” Hamilton joked. “They grew.”

            Hamilton found his way into the field of entomology when he was a graduate student pursing a master’s degree from the University of Kansas. He took a graduate position with the Kansas Biological Survey at a time when the organization was conducting a statewide survey of freshwater invertebrates.

            “Nobody was working on the caddisflies, so I said, ‘I’ll work on them,’” Hamilton recalled. “That’s how I started. I developed my skills out there and then did my Ph.D. at Clemson, where I worked with John Morse, one of the world authorities on caddisflies.”

            It was at Clemson that he met Holzenthal. The two shared a workspace in the university’s insect museum, and they developed similar dissertation topics. But then life happened. Hamilton went to APSU and Holzenthal took a job in Minnesota as curator of that university’s entomological collection. The research they conducted was in danger of being forgotten.

            “Then in 2001, my stepdaughter Hannah started college. She chose the University of Minnesota because, as I joke, she wanted to go to a foreign country for college,” Hamilton said. “Because I’d be coming up there frequently, (Holzenthal) said, ‘why don’t we get to work on this again?’ We started back on it – a week here, a few days there.”

            Their paper, published last month, formally introduced the unknown insects to the world.

            “They’re new species, but some people prefer to say ‘new to science,’” Hamilton said, “since they’ve been there for millions of years and we are just discovering them. That’s the fascinating thing. They’ve been there all along. But this is a very threatened habitat. It’s right next to one of the most populated places in South America. There’s tremendous land development going on, taking down forest. All this alters the watershed and damages the quality and conditions of the streams in which these creatures have thrived for so long. Now, these caddisfly species, members of a group of aquatic insects noted for their sensitivity to poor water quality, may be driven to extinction by those changes to their world. While it does not matter to them, at least they now have a name.”

            For more information on Hamilton’s research, contact the APSU Center of Excellence for Field Biology at 221-7783.