FLASH…flash, flash…FLASH. Tiny lights are sending out a message in code: “Hey, I’m over here. I’m female, and I’m ready to mate.” The pattern of flashes also identifies the firefly’s species. And by the way, this insect isn’t a fly of any kind; it’s actually a beetle.
In the night sky, a male firefly of the same species spots the lights and flashes back: “Message received. I’m coming. I’m coming.” Both partners repeat their messages until the male reaches the female and they mate.
Not all species of fireflies—also called lightning bugs—twinkle, but many of them do. They change chemical energy into light energy, and they’re very efficient at it. Unlike the bulb in your desk lamp, fireflies make light that is almost heat-free. In many species, the light-making organ sits near the end of the abdomen—a taillight of sorts. Some fireflies also produce light in the middle section of their bodies.
Many female flashers are wingless and earthbound, but these glowworms—as they’re sometimes labeled—can twist their bodies around to send their coded messages in different directions. Some also deliver false signals, luring males of different species, then eating them!
Even firefly larvae—also called glowworms—can glow. Scientists think the larvae might use their “taillights” as a warning: “Yucky tasting. Do not eat.” Many larvae spend about two years living in soil, rotten wood, or leaf litter, where they gobble up food such as worms, snails, and slugs. Then each one builds a dirtball around itself and emerges a week or two later as an adult.
Most grown fireflies live less than three weeks. During that time, some of them feed, and some of them don’t, but they all try to mate. Then the species that twinkle put on quite a show. FLASH…flash, flash…FLASH.
Quick Firefly Facts
- A firefly larva can track down snails and slugs by following their trails of slime.
- Some tropical fireflies flash in huge masses. Even in thick jungles, mate-seeking fireflies can spot them.
- Fireflies inspired a grade three class to nominate the bugs as Pennsylvania’s state insect. The class circulated petitions and wrote letters until the “firefly bill” was signed.
- Depending on where they live, some folks believe fireflies are good or bad:
- In Europe, a firefly inside a house is thought to be a sign that someone will die soon.
- In Japan, fireflies are blessed as the spirits of soldiers who have died for their country.
- In some Mediterranean countries, the flashing of fireflies is feared. The light is thought to have come from graves.
- In North America, a glowworm on a path signals success.