E.R. Degginger/Color-Pic, Inc.
The Pennsylvania Firefly is one of many species of fireflies in our area. Fireflies are not flies, but beetles.
Pennsylvania Fireflies are about 1/2 inch long. Their bodies are long and flat. They have large eyes and long thread-like antennae.
Pennsylvania Fireflies have a dull yellowish head. Behind the head is a black spot with a red ring around it.
The wings of this firefly are brown or gray, with yellow bands along the sides and a pale stripe down the middle.
Pennsylvani Fireflies are found in meadows and open woods. They are usually first seen in early Summer.
Males and females attract each other with a flashing green light in their abdomens. The females are wingless and flash from the ground. Males fly about trying to locate them.
After mating, female fireflies lay eggs, one at a time, in rotting wood or dead leaves on the ground. Larvae hatch in the Spring.
After hatching, larvae spend a lot of time eating. They eat slugs, snails, earthworms, aphids, mites and soft-bodied insects. They also eat other species of fireflies. The larva bites its prey and injects it with saliva which turns all of its insides into liquid. Then the firefly larva sucks out the liquid.
The larvae will continue to eat and grow all summer. In the fall, they will dig below the soil surface and wait until the following Spring. At this time, the larvae will become pupae (resting stage). New adults will hatch in early Summer. Pennsylvania Fireflies die after mating.
Eggs and larvae also glow, and firefly larvae are sometimes called "glowworms."
Male fireflies flash every two to three seconds while in flight.
Larvae can detect the slime trail of a slug or snail and track it down.
Adult fireflies will sometimes drink flower nectar for extra energy.
Relationships in Nature:
Relationship to Humans:
Pennsylvania Fireflies are not pests, as some people believe. They do not eat plants other than occasional flower nectar. Instead, they are very helpful. Their main foods (slugs, snails, aphids) are well-known garden pests, and fireflies help control them.
Also, many children have experienced the fun of chasing and catching fireflies. If you catch them and keep them in a jar, remember to let them go after a little while so they can go back to eating slugs!