School Calendar and Seasons

Why They Glow and Other Fun Facts About Fireflies

Growing up in Southern California, fireflies were viewed only in fake form as twinkle lights in the Pirates of the Caribbean ride at Disneyland. Now, having lived in Virginia for nearly a decade, they’re real life glory has become one of the iconic joys of summer for me and my daughter. We were able to share that joy during a visit from our West Coast family last week. A young cousin saw fireflies for the first time.

Watching their vibrant show and catching the glowing bugs to take a closer look are fun, but there’s a lot to know about fireflies, too. So, next time you’re in out with the kids at dusk (or riding Pirates of the Carribean, perhaps) consider taking the opportunity for a quick lightning bug lesson. Here are some interesting facts:

1. How and Why They Glow

According to National Geographic, fireflies have dedicated light organs that are located under their abdomens. The insects take in oxygen and, inside special cells, combine it with a substance called luciferin to produce light with almost no heat. Firefly light is usually intermittent, and flashes in patterns that are unique to each species. Each blinking pattern is an optical signal that helps fireflies find potential mates. Scientists are not sure how the insects regulate this process to turn their lights on and off. Firefly light may also serve as a defense mechanism that flashes a clear warning of the insect’s unappetizing taste. The fact that even larvae are luminescent lends support to this theory.

2. Some of Them Lack the “Lightning”

There are fireflies in the western United States, they just don’t light up. Of the more than 2,000 species of fireflies, only some come equipped with the ability to glow; the ones that are able to don’t generally live in the West.

3. They’re Not Flies

Despite their name, these insects are actually beetles, according to Mother Nature Network. They are nocturnal members of the family Lampyridae. Most fireflies are winged, which distinguishes them from other luminescent insects of the same family, commonly known as glowworms. There are about 2,000 firefly species.

4. Their Babies Live Underground

While it’s true that many an insect larvae lives underground, firefly babes have them beat in the “neat tricks” department; some species emit a subterranean glow. Among some species, even the eggs glow. Females deposit their eggs in the ground, which is where larvae develop to adulthood. Underground larvae feed on worms and slugs by injecting them with a numbing fluid.

5. Their Numbers are Declining

If you’re seeing fewer fireflies each summer, you’re not alone. Anecdotal evidence suggests that firefly populations may be on the decline, most likely due to a combination of light pollution, pesticide use and habitat destruction. For example, according to Smithsonian.com, if a field where fireflies live is paved over, the fireflies don’t migrate to another field, they just disappear forever.

6. You Can Attract Them to Your Yard

These insects live in a variety of warm environments, as well as in more temperate regions, and are a familiar sight on summer evenings. Fireflies love moisture and often live in humid regions of Asia and the Americas. In drier areas, they are found around wet or damp areas that retain moisture. Mother Nature Network offers several ideas for how to attract them to your own yard, such as skipping pesticide use, planting a firefly friendly garden and resisting the urge to put them in a jar.

7. Their Purpose is Pure Joy

Fireflies just bless you with their presence, light up, make love, and call it a life. Vincent Brady was inspired by the simple purpose of these insects and made this beautiful time-lapse video:

Image- YouTube/ Vincent Brady

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