Fireflies: Bright Lights in June

Fireflies: Bright Lights in June

Every year I wait to see them. I saw my first one of 2011 on June 14, at dusk. It was just one lonely firefly, signaling its presence near a bunch of parked cars. For me it was an exciting moment. I am not even sure why. I just love the sight of these glowing insects; they mean summer is here. Their renewed presence means the species has survived yet another year and still exists to tell me it is June. But they are not really flies. So what are they?

Fireflies are actually winged beetles. The 2,000 species of fireflies that exist are found in temperate and tropical habitats around the world. They are also known as lightning bugs and even as glowworms (particularly in their larval phase) and they have these names because of their “conspicuous crepuscular use of bioluminescence to attract mates or prey” (per Wikipedia). In other words, they emit light at twilight to communicate with other insects. The light is produced by a chemical reaction that occurs within a special organ in their lower abdomen. Each species has its own pattern of light flashing to find mates.

Most firefly species are active at night, when their flashing light can be readily spotted. Some species of fireflies are active during the day, but they tend not to be luminescent. However, all firefly larvae glow, presumably as a way to warn would-be predators of their nasty chemical taste. As adults, the light usually signals a willingness to meet and mate. At least one species uses its flashing light for a different – and deceptive – purpose. The female of this type mimics the mating flashes of other fireflies; when a hopeful male responds, he ends up being dinner, not a mate. So much for a “light” dinner!

Of course, I am not the only person who loves watching these bugs. There is a magic to watching children run through a field trying to capture fireflies. Professional institutions are also dedicated to the study of fireflies. The Museum of Science in Boston teams up with university researchers to study firefly sightings each year. Volunteers around the country help them count fireflies as a way of tracking their numbers. It seems that their population has been decreasing, and this could be due to environmental influences. There is even the Kumejima Firefly Museum in Okinawa, Japan, that is dedicated to this amazing insect. The museum celebrates the fact that there are seven species of firefly thriving on Kumejima because of the island’s clean ecosystem.

So, the next time you see some bug flying near you, please don’t reach out to swat it. Just keep an eye on it and you may be rewarded by the glow of a bioluminescent love signal.

Carol