Virgin Palouse Prairie serves as insect refuge

PULLMAN — A 30-plus-acre slope near here may be one of the last, best chances to understand the insect world of the pre-agriculture Palouse Prairie, according to Richard Zack, Washington State University entomology professor .

He and graduate student Jessica Thompson of Chico, Calif., are conducting research on the plot this summer to determine how the insect population — especially the moth population — there differs from the insect population in surrounding agricultural areas.

“The question is: Does it still maintain an insect fauna that probably would have been common throughout the area before we started farming here? The insects aren’t necessarily rare everywhere, but they are rare on the Palouse,” Zack said.



(Photo: Wild flowers found on slope hillside.)

The slope was donated to WSU years ago, he said. It is relatively steep and has never been farmed, and, as a result, features native plants such as wild roses and numerous wildflowers that are no longer prevalent on the Palouse. “It is large enough to support the plants and insects that would have been present throughout the area before farming.”

Once or twice a week, Thompson visits the slope to set up traps. The next day, she records the kind and number of bugs collected. Zack said the study already has produced some interesting results.

“As you would expect, the number of moths there is relatively high,” he said. “But the diversity of moths is much, much greater than what we find in our traps on the adjacent farm land.”

Zack said the research could lead to the preservation of similar areas on the Palouse. “These areas usually are not farmable, so one goal may be to at least map them with the idea of keeping them as natural as possible for the preservation of native plants and insects,” he said. “We’re trying to protect areas of the native Palouse with as little detrimental effect as possible on what else is going on here ­ primarily farming.”

There would be no economic loss to preserving the areas, Zack said, and there could be some very real economic benefits.

“As the use of biocontrols of pests increases, these areas could provide a refuge for the biocontrol agents over the winter or after their particular crop is harvested,” he said. For example, if a variety of wasp is introduced into a wheat field as a way to control aphids, the unfarmed refuges would give the wasps a place to live after the crop is gone.

“There are definitely economic reasons to preserve these relic areas.”