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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Bugging the Northwest: The bright side of this beetle is its stinky warning

A red net-winged beetle photographed near Tacoma uses its showy color to keep predators away.  (Christopher Brett Hamburger)
By Linda Weiford For The Spokesman-Review

If you lived in the woods and knew predators were flitting about that wanted to eat you, you’d probably do your darnedest not to stand out.

But the bright red insect recently photographed near Tacoma takes the opposite approach. Known as a red net-winged beetle, it uses its bright color to warn predators to stay away, according to entomologist Richard Zack of Washington State University.

“It’s a very beautiful beetle,” he said, adding that its striking appearance is an example of critters “using warning colors in nature – from the monarch butterfly to coral snakes to poison arrow frogs.”

There are some 2,800 species of net-winged beetles, and the one observed in Tacoma is most likely Dictyoptera simplicipes, Zack said, found in wooded areas of western North America.

“They’re not common in the Inland Northwest, but we do find them,” he explained.

Not only are these beetles highly visible, but they’re also soft-bodied and slow-moving. No problem, though, because their red color advertises the presence of chemicals that makes them foul tasting, according to Iowa State University’s BugGuide.

Because D. simplicipes feed mainly on dead and rotting trees and plants, they are not considered pests. They make little or no attempt to hide from predators or curious humans, using their vibrant red wing covers, called elytra, as if to blare, “Vile tasting – stay away!” This anti-predator strategy of coloration means they are aposematic, like the black and orange of a monarch butterfly or black and white pattern of a skunk.

The net-winged beetle’s neon warning sign isn’t a bluff. If snatched by an insect or bird, the beetle releases a chemical compound from the base of the elytra that smells and tastes bad.

Net-winged beetles get their name from the intricate network of ridges covering each wing covering, resembling a fine net, Zack said. Considering that there are nearly 3,000 species, it’s not surprising that they come in all kinds of colors and patterns. Some species are solid red, others are orange and one species found in New Guinea is teal. Many species’ wings sport black bands or other patterns on their brightly colored wings.

The net-winged beetle’s strategy of using showy colors to keep predators away is so effective that some moths and other beetle types actually mimic them, Zack said. The mimicking insects lack chemical toxins, so their warning colors are deceptive. In reality, they’d probably make a perfectly fine meal. “The mimics take advantage of the colors and predators avoid them,” Zack explained.