Texas Parks & Wildlife Magazine   




Flashes in the Dark

Whether you call them fireflies or lightning bugs, these flying beetles are evening enchanters.

The approaching darkness is illuminated by faint, intermittent glimmers, like landing lights for tiny airplanes. With a glass jar in hand, you stumble through the gloom toward the firefly’s last blink, hoping to capture one. Another gleam, it’s over there!

Every flash of light reveals more details — a hard exoskeleton, six jointed legs, two antennae, compound eyes and a body.

Just a flying beetle, but this one’s got a taillight flashing.

Interestingly, people call them fireflies in the West, where there are many wildfires, and lightning bugs in the South and Midwest, where the most lightning strikes are recorded. Everywhere else, usage is pretty evenly split.

Fireflies are members of the Lampyridae family. The name comes from the Greek lampein, which means “to shine.” The United States is home to approximately 175 firefly species; 36 of those species are found in Texas. While there are about 2,000 species of fireflies across the world, only some have the ability to glow.

As air rushes into a firefly’s abdomen (in an area called the lantern), it mixes with a chemical called luciferin and creates a spectacular bioluminescence. The firefly can control the air intake, pulsing the light on and off.

The firefly chemical reaction is so unique that medical scientists use this glow-producing chemical reaction to reveal bacterial and viral infections, search for life in outer space and destroy cancer cells.

Firefly light is usually intermittent, and flashes occur in patterns unique to each species to signal mates. The male will send a flash pattern to the female, then she will respond with her own flash pattern. Some species will even synchronize their flashes, creating a beautiful light show. But beware, some female fireflies lure males of smaller species and eat them.

Fireflies also flash to deter predators. A firefly’s blood contains lucibufagins, toxic defensive steroids that taste bad. After one nasty bite, the bad taste is associated with the firefly’s light and predators learn not to eat them.

Fireflies are in decline, and scientists want to know if you see them. See fireflies’ glimmering starting as early as late May, especially on warm, humid evenings. If you catch one, make sure to release it soon. Share your photos on your favorite citizen science platform.

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