Fireworks & Fireflys

Have you ever noticed the evening fireworks show in your yard that starts around the 4th of July every year? Summer means fireworks and fireflies. It turns out that fireflies, also known as lightning bugs, are really neither flies nor bugs; they’re soft-bellied beetles – members of the family Lampyridae, which means “shining fire.” Many of us spent our childhood evenings catching fireflies in a jar.  Fireflies, also known as lighting bugs, are really a type of beetle with a fantastic ability to make their posterior glow. There are many species of fireflies in the world and the light the adults produce can be yellow to red. In fact, one species of fireflies has eleven pair of green lights on its thorax and a pair of red ones on its head; now that is a light show! Edison must have been envious of fireflies. When you watch a firefly you are witnessing a chemical reaction. A substance called luciferin is stored in the beetles light organ. The light organ has many air tubes in it along with reflectors. When oxygen and luciferin combine in the presence of enzymes, light is produced. The reflectors help to disperse the light. Fireflies control the light by how much and how often they let oxygen into their light organs. Now you may ask, “why do fireflies go to so much trouble?” Finding a mate and finding food make the world go ‘round so that’s always a good guess. Fireflies flash to attract a mate. And not just any mate but a mate of their same firefly species. The flash code is very specific to the species. They’re quite common in the United States, but only east of the Rocky Mountains. They need a warm humid landscape and thrive in woodlands, fields, and grassy areas near lakes and streams. The light they produce is created by a brief chemical reaction in a dedicated light organ, yellowish in color, located under the abdomen. The light is called “cold light” because virtually all of the energy consumed goes into light, not heat. The light communicates with other fireflies, mostly to attract mates. The show generally begins in early June, before the June 21 summer solstice which marks the beginning of summer. It runs for about 30 minutes each night, starting around sunset Typically after sunset the male firefly patrols grassy areas while he flashes his code. The females hang out on low vegetation and if she is interested she flashes back the same signal. After exchanging signals about five to ten times the male finds the female and then it’s “lights out.” Adult fireflies eat small insects if they feed at all and they don’t bite people. The young fireflies live underground and don’t look anything like their parents. Their spindle shaped bodies glow continuously and are often called glowworms. Your landscape and garden contain creatures more fascinating than any science fiction story. Take a moment to get away from the city lights to enjoy a real light show. If you share a fascination for fireflies consider joining a network of citizen scientists involved in Firefly Watch. You can track and report on your own fireflies. The website also has a ton of great info on the biology of fireflies.

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