Life Stages of a Scorpion Fly

Reproduction

• The male scorpion fly exhibits complex courting behavior. He attracts the female with food, either a dead insect or a bit of brown salivary secretion, emits a pheromone from vesicles in his abdomen, vibrates his wings, or stridulates. The female arrives, and the male mates with her while she feeds. Sometimes copulation is forced. Later, the female will lay clusters of eggs in the soil.

Larvae

• Scorpion fly larvae that hatch resemble caterpillars. They have a hard head, mandibles, setae or hair projecting from their abdominal segments, and four to eight sets of prolegs. They live in underground burrows, and come up to eat decaying organic matter and soil insects like proturans. The larvae of the scorpion fly feed for about a month, and molt four times.

Pupation

• The scorpion fly larva makes a cavity in the soil to shelter it through a resting stage that lasts about five weeks. After this it pupates, which lasts two to three weeks. The pupa loses the mandibles of the larvae. Scorpion flies can pupate till late summer, when the adults of some species emerge, or over the winter if they are from a species that emerges in the spring.

Adult

• The scorpion fly is from 0.4 to 0.47 inches long, though the rare Florida scorpion fly is larger at 0.72 to 0.73 inches. Most scorpion flies are reddish brown, with wings that are transparent or a bit yellowish. They hold their wings swept back when at rest, which gives them a "V" profile. The wings are spotted, with larger spots near the edges of the wing and smaller spots near the base. The head has a beak. The female lacks the male's "stinger" and her abdomen tapers to a tip. Scorpion flies live in woodlands, in low shrubs near water or wet places, grasslands, cultivated fields and the borders of forests. The adults can be found on leaves in shaded areas less than 3 ft. from the ground. The adults are scavengers and eat dead or dying insects, vertebrate or snail carrion, live slugs, bird droppings, pollen nectar or fruit juices. Some scorpion flies live in spiderwebs and eat dead or trapped insects and, if they can, the resident spiders. Scorpion flies give off a foul odor if they're mishandled.