Fireflies are more than meets the eye

Published 12:00 am Sunday, July 31, 2011

“You would not believe your eyes, if ten million fireflies lit up the world as I fell asleep.”

If you have not heard the song, you should. I love it! Lightning bugs are one of the happy things about summer and one of my favorites.

“Lightning bug” is the name that we used when I was growing up, but fireflies seems to be more common around here. (Okay, so we really called them lyte-nin’ bugs, but I have worked hard on my speech patterns.) In days past, kids would collect them by hand and put them in jars to fall asleep by. (Parents: Be sure to release them when the kids are asleep.)

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Today, I don’t think they make a video game with lightning bugs, but if they did I’m sure my daughter would have it. Outside, she’s not so interested.

“Cause I’d get a thousand hugs from ten thousand lightning bugs…” Lightning bugs emit light in a special pattern to attract mates.

They also can use light to defend their territory or warn predators. Sometimes only the female lights up, sometimes only the male, but in most both species glow. Females often flash from a tree or a shrub and entice the male to fly in.

Fireflies are beneficial insects. As larvae, they eat other insects, snails and worms. Some mimic other species: the females flash to attract and then eat the other species males. Since fireflies are very short lived (think: mate, lay eggs and die), they may not eat as adults. Larvae will live for about a year or one mating season to the next.

“Everything is never as it seems.” The bioluminescence from lightning bugs (and others) is the most efficient type of light.

All of the energy is emitted as light. Only 10 percent of an incandescent bulb is light (the remainder is heat) and even a fluorescent bulb is 90 percent light and 10 percent heat.

Bioluminescence is “cold light.” Two chemicals occur in the firefly tail: luciferase and luciferin. The luciferase enzyme tells the luciferin to light up using ATP for energy. (ATP is the chemical that stores and releases energy in all living animals.)

These two chemicals are found in adult and larval lightning bugs. Even the eggs can emit light. Sometimes they will flash when gently tapped.

In science and medicine, these chemicals are used to prove the presence of ATP. Diseased cells may have too little and cancer cells may have too much. The light or glow makes it easy to determine the amount. In space, the chemicals have been place on electronic detectors to detect alien life. It can also be useful to determine food spoilage or bacterial contamination.

“I’ll know where several are, if my dreams get too bizarre ‘cause I saved a few and I keep them in a jar…” Fireflies may be easy to catch, but don’t eat them, they are toxic. (Remember this Odie.) Pet reptiles have died from eating fireflies.

“I got misty eyes as they said farewell.” But fireflies may be becoming a thing of the past. Numbers of lightning bugs are falling. The complete reason is unknown, but open forest and fields are being used for human activities, which means less habitat for lightning bugs. Pollution and pesticides may also affect firefly populations.

And then light pollution probably plays a big factor. Some species synchronize their flashes across large groups of thousands of insects. The light from homes, work, cars and streetlights may make it hard for fireflies to signal each other. This means less successful mating and therefore less fireflies next year.

“I’d like to make myself believe that Planet Earth turns slowly.” This new popular song is the author’s attempt to translate fireflies into electronics. I hope that this is not the only way my grandchildren have to appreciate lighting bugs.

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MJ Wixsom practices veterinarian medicine at Guardian Animal Medical Center in Flatwoods, Ky. For questions, call 606-928-6566.