Insects welcome in one wild patch
PULLMAN – Across the Palouse, wheat and pea fields drape the landscape, a quilt of broad, uniform patches.
But hundreds of years ago, before the plow and the combine, the prairie was dense with plant varieties – native roses and geraniums, grasses and wildflowers, mint and juniper.
And moths. A big, wide world of moths.
“Most people misunderstand moths, because they’re so used to seeing these brown, ugly things flying in the porch light,” said Richard Zack, an entomology professor at Washington State University.
Zack and WSU graduate student Jessica Thompson are gathering hundreds of examples to the contrary: tiny “micro-moths” with delicate tan wings, large European moths with brown and orange wings, moths whose wings sport pink and pale yellow patterns. They’re finding the insects on a rare 30-acre patch of Palouse – an unfarmed island in a sea of agriculture.
“This is basically native Palouse,” Zack said Wednesday, standing in the brushy “remnant prairie” south of Pullman. “As far as we know, the land has not even been grazed. It certainly hasn’t been plowed.”
Thompson’s moth project will conclude this year, but Zack foresees a decade or more of further research at the plot, which was donated to the university years ago. The studies will help provide baseline information about insect populations and suggest possible ways of using “biological controls” for pests that damage crops.
“Instead of looking for a chemical to kill them, we’re looking for a wasp that attacks them,” Zack said.
It’s possible, Zack said, that small pieces of undisturbed land, such as the one being studied, could provide a safe haven for “good” bugs that could then venture out into the fields to feast on the bad ones.
The Palouse has world-class conditions for growing wheat and peas, among other crops. But the effect of replacing a diverse collection of plants with single-crop fields reduced the number of insects on the land and made it easier for some pests to take hold.
In the months that Thompson has been collecting moths, she has found thousands of insects from about 250 species. In the same time, a wheat field might produce dozens of moths, of two or three species.
In the virgin prairie, each moth feeds on a single plant, and four or five moths might each feed on a different part of a plant. “It starts to snowball until you’ve got several hundred moths out there dividing that up,” Zack said. “When you go to a wheat field, you’ve got one plant.”
Zack has been a professor studying insects and their environments at WSU for more than 20 years. He’s the director of the M.T. James Entomological Collection, a bug “library” that includes more than 1.25 million insect specimens. He is also known for his regular “bug fest,” where hundreds of people show up to munch on insects in a variety of forms.
The study on the Palouse is part of a larger study of moths in the region that Zack and other scientists are engaged in. It’s part of his interest in the way that insects interact with their environments.
“Probably no group of organisms tells you more about what’s going on in the world than insects do,” Zack said.