Gloucester County Nature: Lightning bugs add sparkle to the Summer sky

Gloucester County Times By Gloucester County Times Gloucester County Times
on July 21, 2009 at 3:00 AM, updated July 21, 2009 at 11:30 AM

By Erik Mollenhauer, The Gloucester County Nature Club

Special to the Gloucester County Times

What would a mid-summer evening be like in Gloucester County without the flash and sparkle of lightning bugs?

Taken for granted by people who have grown up here, visitors from other parts of the U.S. and world who do not have lightning bugs are enchanted to witness their presence at dusk. Over the years many children in Gloucester County have collected lightning bugs in jars to create a night light.

Lightning bugs belong to a family of beetles, the Lampyradie, best known for their ability to make light. Also known as fireflies, they overwinter as larvae buried in damp soil, emerging in spring and feeding in swampy areas. In early summer, the larvae pupate in a small earthen cell, emerging as adults after two and a half weeks. The adults fly about mid-summer skies at dusk, making light signals to attract a mate.

Most of the lightning bugs that you see are males, since the males signal when flying and the females signal from perches on or near the ground. Once the male and female mate, the female lays eggs on or just under the soil for the next several days. The eggs take up to four weeks to hatch. Then the larvae begin feeding in the soil, until fall, when they burrow underground and overwinter.

Different species are active at different times during the night, and different species have different signal patterns. The patterns may differ by: the duration of the flash, the interval between flashes, the number of flashes in a complete signal, the distance flown between signals, or the color of the flashes. Some species signal just before sunset and others just after sunset. Some species signal for only half an hour and others flash for several hours. Each species restricts its activity to certain habitats, such as swamps, woods or open meadows.

As the male flies over areas where there are likely to be females, he signals. If a female sees his flash from her perch, she responds with her own flash of light. When the male sees the female's flash, he moves closer. Through a series of signals and responses, the male finds the female and mates with her.

The female usually stops signaling after mating, although in one species the female will continue to signal to males of other species. When the males come near, the female captures and eats them!

Most lightning bugs are nocturnal but some species fly by day. Their total lifespan is a year or two, but the adults typically only live a few months.

Some other insects make light but only lightning bugs flash it on and off in distinct signals. Luciferin, the chemical substance in the tip of their abdomen that makes the light, without producing heat, is used in laboratory studies as an indicator of chemical reactions.

Even the larvae of lightning bugs have the ability to glow, though it is not understood why, since they do not use the light to attract a mate at that time. Both the larvae and the adults are carnivorous and eat other insects, as well as snails and small ground animals.

Some of the best places to find lightning bugs are over meadows and lawns, at the edges of woods, streams and marshes. Lightning bugs breed in moist environments, under leaves and debris, bark and decaying vegetation, in many different habitats, so a thoughtful gardener should maintain a corner of their yard with decaying leaves and native vegetation.

For information about the Gloucester County Nature Club, visit