The order Mecoptera is a truly ancient group of insects, with a fossil record dating back to the early Permian period. The name Mecoptera derives from the Greek mecos, meaning long, and pteron, meaning wing. Scorpionflies and hangingflies are uncommon, though you can find them if you know where and when to look.
The scorpionflies and hangingflies range from small to medium in size (species vary from 3-30mm long). The scorpionfly body is usually slender and cylindrical in shape, with a head that extends into a pronounced beak (or rostrum). Scorpionflies have prominent, round eyes, filiform antennae, and chewing mouthparts. Their legs are long and thin. As you probably guessed from the etymology of the word Mecoptera, scorpionflies do indeed have long wings, relative to their bodies. In this order, the front and hind wings are roughly equal in size, shape, and venation, and all are membranous.
Despite their common name, scorpionflies are entirely harmless. The nickname refers to the odd shape of the male genitalia in some species. Their genital segments, located at the end of the abdomen, curve upward like the sting of a scorpion does. Scorpionflies cannot sting, nor are they venomous.
Scorpionflies and hangingflies undergo complete metamorphosis, and are some of the most ancient insects known to do so. Scorpionfly eggs actually expand as the embryo develops, which is quite an unusual trait in an egg of any organism. The larvae are most often thought to be saprophagous, though some may be herbivorous. Scorpionfly larvae develop quickly, but have an extended prepupal stage of one month to several months long. They pupate in the soil.
Habitat and Distribution:
Scorpionflies and hangingflies generally prefer moist, wooded habitats, most often in temperate or subtropical climates. Adult scorpionflies are omnivorous, feeding both on decaying vegetation and dead or dying insects. Worldwide, the order Mecoptera numbers about 600 species, divided among 9 families. Just 85 species inhabit North America.
Families in the Order:
Note: Only the first five families in the list below are represented by extant North American species. The remaining four families are not found in North America.
- Panorpidae – common scorpionflies
- Bittacidae - hangingflies
- Panorpodidae – short-faced scorpionflies
- Meropeidae - earwigflies
- Boreidae – snow scorpionflies
Families and Genera of Interest:
- Just a single species is known from the family Apteropanorpidae. Apteropanorpa tasmanica inhabits mosses in Tasmania, an island state off the mainland of Australia.
- Hangingflies (family Bittacidae) resemble crane flies, but they are unable to stand upright on surfaces as crane flies can. Instead, the predaceous adults hang from stems or leaves by their front legs, and grab insect prey with their raptorial hind legs.
- Use a Malaise trap to catch specimens of Merope tuber, the only North American species of earwigfly.
- Don't handle snow scorpionflies (family Boreidae)! They're so well adapted to cold climates, the warmth of your hand can kill them.
- Borror and DeLong's Introduction to the Study of Insects, 7th edition, by Norman F. Johnson and Charles A. Triplehorn.
- Mecoptera, by Dr. John Meyer, North Carolina State University. Accessed December 26, 2012.
- Family Dinopanorpidae, Bugguide.net. Accessed December 26, 2012.
- Gordon's Mecoptera Page, Gordon Ramel. Accessed December 26, 2012.
- World Checklist of Extant Mecoptera Species, California Academy of Sciences. Accessed December 26, 2012.