Earwigs get a bad rap—and it’s time to set the record straight.
First off, they don’t seek solace in human ear canals. That seems necessary to state right up front, since the idea is baked into their very name. As the Oxford English Dictionary notes, “the belief that the earwig has a habit of crawling into the human ear, although apparently unfounded, is a long-standing and widespread one.” This impression is recorded in sources beginning in the Middle Ages and is reflected in many languages. Its old French name, perce-oreille, for example, translates to “pierce-ear.”
The earwig’s scientific nomenclature is more instructive. The 2,000-plus species of earwig are part of the order dermaptera, meaning “skin wing.” That might not do much to assuage their gross-out factor, but it nods to the importance of their wings, which, when unfurled, are shimmering things of beauty.
Indeed, earwigs have some of the most incredible wings in the animal kingdom. Normally tucked away and completely hidden, they expand to 10 times or more their size during flight, when the insects are seeking out food or mates.
This is a handy trick, and one that has mesmerized generations of curious naturalists and engineers alike. Incredibly, the wings are able to unfold and lock into place—not to mention also unlocking and folding back up—without any direct muscle activation.
A group of researchers led by Andres Arrieta, assistant professor of mechanical engineering at Purdue University, recently published a paper in Science about how earwigs’ wings work. When the team tried to model the unfolding mechanism using a traditional understanding of origami-like folding, it did not compute. The wings simply do not fold like typical well-known materials (think paper) at a single crease.
Instead, Arrieta’s team found that the wings work by possessing spring-like folds, which have two stable configurations. He likens them to slap bracelets, which can stably switch between two different orientations.
Beauty in the beast
Julia Deiters, a researcher at Germany’s University of Duisburg-Essen who recently co-authored a study on the topic, says the wings are also stabilized by folds that are bended, as opposed to straight. These arrange mechanical forces in a way that enables the wings to “lock,” either when they are completely open or folded up.
Deiters says after seeing an earwig’s wing for the first time, she decided she had to study them. “They’re lovely,” she says.
Now, after working with earwigs for years, Deiters says she’s noticed that the creatures possess unique personalities. In some ways, she says “they behave like humans,” including the elaborate courtship displays with which males attempt to woo females.
Most species of earwigs possess very similar wings, but the majority of species don’t use them frequently. The exact purpose of earwig flight—and the conditions that prompt it—remain murky for entomologists.
Arrieta and others hope to use their insights into the wings’ mechanisms to create mimics in the future. “The wing gave us the recipe to make similar manmade materials,” he says. Such materials could be an invaluable tool with potential applications for making things like quick-assembly tents, portable solar panels, and compact electronics.
This tropical jewel moth, Acraga coa, is found mostly in Central America. Jewel moths undergo a spectacular transformation: from translucent larvae covered in protective goo to vibrant fuzzy fliers.