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The magical world of fireflies


Photo by Moran Brenn licensed CC BY 2.0

After sundown, summer nights become magical when the fireflies flash their brilliant behinds in a spectacular display of lights. With approximately 2,000 firefly species around the world, these night-loving insects can be found near wet and wooded areas.

Because “firebeetle” doesn’t do it justice

firefly photo

Photo by terry priest licensed CC BY-SA 2.0

Call it a lightning bug, a glow bug, or a firefly. Just as long as you remember it’s a winged beetle, not a fly! Fireflies are from the Lampyridae (say “LAM-puh-rid-eye”) family, which sets them apart from all of the other beetles. To be a member of this special family, a beetle must be able to glow.

How they glow

little girl looking at a jar with fireflies in it

Photo by Jim Miles licensed CC BY-NC 2.0

Fireflies have a special light-making organ, called a photic organ, located just below their abdomen. To make light, the fireflies take in oxygen, which mixes with a natural substance called luciferin (say “loo-SIF-er-in”) found in the cells of these organs. A recently discovered  oxygen electron called the superoxide anion causes a chemical reaction to occur and the fireflies light up. This whole process is called bioluminescence.

Flashing lights mean “I like you”

firefly sitting on a flower and flashing

Photo by Mike Lewinski licensed CC BY 2.0

Fireflies use bioluminescence to communicate and find potential mates. Remember, these bugs have one thing on their mind: babies! Each firefly species has their own unique light pattern so they can attract mates of the same species. It works like a flashing fingerprint, which is helpful when they need to find each other in the dark.

More efficient than the most energy efficient light bulb

a blinking firefly on a man's hand

Photo by Marty Gabel licensed CC BY-NC-ND 2.0

When a firefly lights up, it produces almost no heat. Unlike a light bulb, nearly all of the energy source emitted from the firefly is light. This is a win for the firefly because otherwise the poor bug would literally go down in flames.

Double trouble

a firefly in the air showing its double set of wings

Photo by terry priest licensed CC BY-SA 2.0

Fireflies have two pairs of wings! The forewings, called elytra (say “EL-i-truh”), are hard and act as a shield to protect the abdomen. When in flight, the firefly holds out the elytra for balance—picture the wings of an airplane—while the soft and leathery hindwings beat and help control the beetle’s movement.

Some fireflies EAT other fireflies by tricking them

the Photuris firefly

Photo by Ian Marsman licensed CC BY-NC-ND 2.0

It’s true, female Photuris fireflies dine on other species of fireflies! In order to lure in her prey, she uses a technique called aggressive mimicry. The female waits for a Photinus or Pyractonema to flash. She then imitates his pattern. By doing this, she tricks the male firefly into thinking that she is from his species and she is willing to mate. As soon as he is close enough, the unsuspecting male is surprised to find out that *GULP* he’s become her next meal!

Altogether now

a field full of lit fireflies

Photo by Zach Ho licensed CC BY-NC-ND 2.0

Simultaneous bioluminescence is an incredible phenomenon where fireflies flash at the SAME TIME! This only happens in two places (TWO!) in the ENTIRE WORLD: the Great Smoky Mountains National Park in Tennessee, USA, and southeast Asia.