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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

Dashing through the snow: Snow scorpionflies, Boreus sp.


On a wintry day, moss makes a fine meal for a snow scorpionfly.


With the return of cold winter weather to our region, is it time to bid farewell to the outdoor insects we have visited in many previous episodes of Bug of the Week? Not at all! Even on chilly days in January and February, many cold hardy insects enjoy their day in the winter sun. Recently we met the strange cankerworm moths (see  A moth in winter - the fall cankerworm, Alsophila pometaria) basking in the January sun on the bark of trees, and several years ago we were introduced to the tiny snow fleas (see Small Olympians - Snow fleas, Collembola) cavorting on freshly fallen powder. Today you will meet one of the rarest insects we will feature in Bug of the Week: snow scorpionflies. 

Neither snow nor ice can cool the romance between male and female snow scorpionflies.

Discovered near the banks of an icy stream recently by one of my colleagues, snow scorpionflies are not scorpions, nor are they flies. They belong to a small order of insects known as Mecoptera. The “snow” part of their common name comes from the habit adults have of dispersing between breeding areas by running across open snow. The "scorpion" moniker derives from the fact that males in this group have unusually large and upward curving genitalia that resemble the stinger of a scorpion. However, in spite of its impressive looking “stinger” and a long rostrum (snout), this insect does not sting or bite. The "fly" part of the name comes from the fact that many species of Mecoptera have wings and can….well, fly. However, the tiny snow scorpionflies featured in this Bug of the Week lack functional wings and cannot fly. Go figure! Most species of snow scorpionflies are boreal and live in chilly places such as Alaska and Canada or occupy high elevations in mountains. They are active during the colder months of the year and can be seen with some regularity hopping about in the snow. 

In Maryland, snow scorpionflies can sometimes be found in the dead of winter on snow, ice, or on the mosses and liverworts that serve as food for both adults and their larvae. In one of the more curious mating rituals in the insect world, the male scorpionfly grasps the female and places her on his back for a nuptial ride. If you hope to glimpse these fascinating creatures, dress warmly and bring along your magnifying glass. Snow scorpionflies are tiny insects, usually five or less millimeters long. Snow scorpionflies are believed to be the ancient relatives of one of our more well-known and itchy insect acquaintances, fleas.


Many thanks to Jeff Shultz for sharing his snow scorpionflies for this Bug of the Week.

To learn more about these interesting insects, please visit the following web sites: