Mississippi State University researchers are shifting commonly held ideas about the diet of grey wolves in a newly published article gaining national attention.
Published in the scientific journal "Ecology," MSU assistant professor Brandon Barton's Sept. 18 article "Grasshopper consumption by grey wolves and implications for ecosystems" details the unexpected effects of wolf reintroduction into the western region of the U.S.
MSU entomologist and grasshopper expert JoVonn Hill, an assistant professor in the Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, and a scientist in the Mississippi Agricultural and Forestry Experiment Station, also assisted with the research project and article.
Other co-collaborators on the paper include Carter L. Wolff, an MSU biological sciences Ph.D. student from St. Joseph, Michigan, Thomas M. Newsome of the University of Sydney, Australia, and William J. Ripple of Oregon State University, as well as Marcus A. Lashley, a former MSU faculty member now at the University of Florida's Department of Wildlife, Ecology and Conservation.
"Ecosystems are complex and connected in ways that we can't always predict," said Barton, an MSU Department of Biological Sciences faculty member who studies how speciesí interactions with one another are affected by the environment.
While on a hiking trip in Hells Canyon Wilderness along the Oregon-Idaho border to study elk ecology, Barton and Lashley stumbled upon wolf excrement containing the remains of 181 grasshoppers.
Barton said the discovery that wolves, as known predators, can eat grasshoppers has implications sending ripple effects through the ecosystem. Hill pointed out that the findings demonstrate the importance of considering multi-organismal links when working with food webs.
"Wolves indeed do eat more than just vertebrate prey, and grasshoppers are more than just spider or bird food," Hill said.
The grasshopper taxonomist said he was "amazed" to identify the grasshopper species after they had been partially digested, which Hill said "adds a unique bit of information to the life history data for the Melanoplus payettei (short-winged grasshopper)," about which very little is known.
Barton said wolves once roamed the country from coast to coast.
"Government sanctioned programs of trapping, poisoning and hunting led to the extermination of wolves in the continental U.S. by the mid-1900s," Barton said.
However, nobody studied the ecological roles of wolves before killing them, Barton said. Wolves were reintroduced for the first time in central Idaho and Yellowstone National Park in the mid-1990s. While the wolves once covered more than two-thirds of the country, today they can be found in Alaska, northern Michigan, northern Wisconsin, western Montana, northern Idaho, northeast Oregon, and the Yellowstone area of Wyoming, according to the National Wildlife Federation.
"Emerging research has shown that they are monumental in restructuring the forests in which they live," Barton said. Without wolves, elk were overabundant, which led to overgrazing, damaging plant communities.
"The reintroduction of wolves has been linked to healthier forests and healthier streams—due to shade from plants which cools water for trout and other animals—and healthier beaver populations," he said.
This newest discovery of grasshoppers in wolf excrement takes Barton's research a step further.
"We now know that wolves interact with grasshoppers. Grasshoppers are extremely important herbivores that can alter plant communities, and in many places are a pest because they target the high-protein plants that livestock need," Barton said.
"Our discovery of a lone wolf foraging on grasshoppers gives us insight into how lone wolves keep from starving," he explained. "Alternative prey, like grasshoppers or river otters, may keep them going until they can meet up with a few other lone wolves. Together, those wolves can establish a pack and interbreed to maintain genetic diversity, and keep spreading back to their historic ranges across the country."
The reintroduction of wolves proves more each day about the "interconnectedness of these ecosystems," Barton said.
"Last year there was a documentation of a lone wolf on the Pacific Coast that is hunting river otters, and now we find evidence that they are gorging on grasshoppers. Nobody would have predicted such a thing," he said.
Part of the College of Arts and Sciences, the Department of Biological Sciences can be found online at www.biology.msstate.edu. MSU's Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology in the College of Agriculture and Life Sciences is online at www.biochemistry.msstate.edu.