Fireflies (Lightning Bugs)

Media
image of Firefly crawling on a leaf
Scientific Name
Approx. 175 species in North America north of Mexico
Family
Lampyridae (fireflies) in the order Coleoptera (beetles)
Description

There are a number of firefly species in our state. The adults of most species are readily identified by their brown or black, soft bodies, somewhat leathery forewings, and a usually red or orange pronotum (a shieldlike plate) that covers the head from above. The last few segments of the abdomen are pale yellow and can glow yellow, green, or sometimes red, depending on the species. They are our only flying, bioluminescent insects.

The larvae, called glowworms, are wingless. They don’t blink, but they do glow continuously and can be seen on the ground, especially in moist areas near grass and brush.

Size
Length: to about ¾ inch.
Where To Find
image of Fireflies Lightning Bugs Distribution Map
Statewide.
These beetles are nocturnal and crepuscular (active at dawn and dusk) and are usually seen in spring and summer, when the winged adults fly, the bioluminescent tips of their abdomens winking on and off. They’re commonly seen in meadows, yards, edges of forests, and around streams. If you want to encourage fireflies in your area, avoid using broad-spectrum insecticides.
The larvae are voracious predators with jaws equipped with toxin to help them overpower snails, slugs, earthworms, and other prey. Adults eat a variety of foods, depending on the species.
Common throughout the state.
Life Cycle
These beetles overwinter as larvae and in spring they metamorphose into adults. The flashes and accompanying movements are used for courtship. The different species have their own precise rhythms, flashes, and movements; some species lack bioluminescence altogether. Some firefly species mimic the courtship signals of others, lure in prospective “mates,” and then eat them.

The larvae help control snails and slugs, banes to the gardener

The flashing adults are endlessly entertaining to children and adults. Their quiet presence adds to the magic of a Missouri summer night. It's one of the true wonders of nature to see thousands of fireflies winking all across a low fallow field, or, if you're lucky enough, to see an entire group of fireflies in a stream valley winking on and off in unison. In our area, try looking for this phenomenon starting in early June.

Many scientists use luciferase (the bioluminescent enzyme) in gene research, as a way to observe biological processes, and in forensic research.

Old-time Ozark tradition held that the appearance of fireflies meant that cold weather was over and it was safe to set out tomato plants.

The larvae help control populations of the various invertebrates they prey on; the adults are rarely preyed upon, as they contain chemicals that make them distasteful to predators.

Occasionally, an entire group of fireflies in a location (often in a low area like a creek bed) will blink in unison. It is a spectacular sight, and scientists aren't quite sure why or how it happens.

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About Land Invertebrates in Missouri
Invertebrates are animals without backbones, including earthworms, slugs, snails, and arthropods. Arthropods—invertebrates with “jointed legs” — are a group of invertebrates that includes crayfish, shrimp, millipedes, centipedes, mites, spiders, and insects. There may be as many as 10 million species of insects alive on earth today, and they probably constitute more than 90 percent all animal species.