Dobson Flies

Facts, Identification

Insect Name

Order Megaloptera


Found in North and Central America, the dobsonfly is an insect with a frightening appearance. Their long, thin bodies resemble those of the stick insect and can measure up to 12 cm from pincers to wingtips. Dobsonflies are found primarily outdoors near large bodies of water. Indoor infestations would not be possible, since they are incapable of reproducing indoors.

Although the pincers of the male dobsonfly appear threatening, they are harmless. Rather, female dobsonflies use their smaller jaws in self-defense and are capable of piercing the skin if handled. While these bites can prove mildly painful, dobsonflies are not known carriers of any diseases. Dobsonflies may emit unpleasant odors when threatened.

Behavior, Diet & Habits

Adults typically do not feed. They are attracted to lights and may been seen resting on walls near outdoor light fixtures. Larvae are aquatic and predators of other aquatic organisms. They possess strong mandibles which are capable of delivering a very painful bite if handled. Fisherman sometimes us them as bait for fish.


Females lay eggs in fast-moving streams and rivers. Dobsonfly larvae emerge and often hide under rocks and in crevices. They go through a series of molts until they pupate into adults.

Signs of a Dobsonfly Infestation

Since dobsonflies do not infest the indoors of a home, they don’t necessarily have any signs. The only indication homeowners have that dobsonflies are present would be the adults attracted to lights.

Dobson Fly Larvae Bites – Signs and Symptoms
Dobson flies become adults after an underwater larvae stage known as hellgrammites. Typically living under rocks in flowing rivers and streams, hellgrammite larvae feed on small, soft-bodied insects. Their heads are equipped with sharp pincers capable of delivering painful bites to humans. While hellgrammites are not aggressive, bites from these larvae often pierce the skin and cause very minor bleeding.

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