Southern beetle species moving into Nebraska
Released on 06/17/2008, at 2:00 AM
Office of University Communications
University of Nebraska–Lincoln
As curator of insects at the University of Nebraska State Museum, one of Brett Ratcliffe's jobs is to keep an eye on the kinds of six-legged creatures that live in Nebraska, with a particular interest in his specialty, the scarab beetles.
And what he and his team of entomologists are finding is a changing population, with several southern species of scarabs moving into the state in the last several years. Ratcliffe and his colleague, Matt Paulsen, recently published an updated version of the NU State Museum monograph, "The Scarabaeoid Beetles of Nebraska," in which he and his team document 256 species of scarabs living in Nebraska. That's an increase of 57 species since 1991 when the previous edition of "Scarabaeoid Beetles of Nebraska" was published.
"That's quite a dramatic increase, partly because of a different sampling regimen, but also because we are noticing 10 to 12 species that we know were not here in 1991, but that are here now, and these are species that are typically more southern in their distribution," Ratcliffe said.
"We are attributing this to a northward movement of populations due to climate change -- in other words, global warming. These are species that are associated with warmer climates than what we had here in, say, 1990, and now they are here."
Ratcliffe said that while similar phenomena with plants and other types of insects have been noted in Europe and in many parts of the United States, it's the first instance he's aware of where the phenomena has been documented for scarab beetles in Nebraska.
"One of the largest scarab beetles in Nebraska now is one of these new animals," Ratcliffe said. "It's a dung beetle by the scientific name of Dichotomius carolinus. It's half again as big as your thumbnail and it's a generalist feeder. It feeds in all kinds of dung, primarily in pastures."
Another example, he said, is the common green June beetle, Cotinis nitida, which is very common in the southeast United States. In 1991, Ratcliffe said there were only three or four records of it in Nebraska. Now, the beetle can be found in abundance along the Missouri River to north of Omaha.
And then there's the elephant stag beetle, the largest stag beetle in the United States at about 2 1/2 inches long. After the 1991 book came out, a teacher in Beatrice found one. Since then, Ratcliffe's team has seen active populations in Indian Cave State Park near Auburn.
"They look ferocious, but they're harmless, as are all scarabs," Ratcliffe said. "They can't physically hurt you. They don't sting or bite and some are of economic importance. Dung beetles are extremely beneficial for removing animal waste from pasturelands. Having natural recyclers like dung beetles is really important to the ecosystem."
The purpose of the new book, Ratcliffe said, is to document all scarab beetles in Nebraska, provide keys for identification (including illustrations), distribution maps and locality records, and discuss the biology and ecology of each species. It will serve as an identification manual for a large user group in the state, including scientists, educators in extension and outreach, 4-H, students studying insects, museum collections managers and a large amateur community of nature watchers. Most of the 256 species are illustrated with photographs and nearly all have distribution maps showing the counties where they occur.
The first link below is to a color JPEG image of one of the southern scarab beetle immigrants, Lucanis elaphus, first found in Nebraska in 2002 and now with an active population in Indian Cave State Park. The second is to the cover of "The Scarabaeoid Beetles of Nebraska" in Adobe Acrobat PDF format.