Firefly Light Shows could become a Thing of the Past

Seeing fireflies appear all at once in your own backyard, as if a sparkling cloud hovering above the grass, is pretty cool—almost magical. It’s as if a Disney movie is coming to life right in front of you. 

Researchers know fireflies glow as part of the adult mating ritual. What’s not known, is how long fireflies will continue to light the night. Scientists all agree that fireflies are disappearing from forests, fields and marshes all over the country. In fact, fireflies may eventually fade forever, all over the world. 

Researchers blame two main factors: development and light pollution. 

Most species of fireflies live as larvae in rotting wood and a mix of leaves, branches and grasses that litter the forest floor. As they grow, fireflies pretty much stay where they are. However as more and more land is paved over, the fireflies’ habitat disappears. 

Scientists are also concerned that light pollution is harming fireflies. Both male and female fireflies use their flashing lights to communicate; they speak a language of light to attract mates, defend territory and warn of predators. 

But human light pollution is believed to interrupt firefly flash patterns. Researchers have observed that synchronous fireflies get out of synch for a few minutes after a car’s headlights pass. It’s believed that light from homes and streetlights could also make it difficult for fireflies to signal each other during mating. That would mean fewer firefly larvae are born next season. 

More research is needed, but observation reveals that the wonder of firefly magic could be growing increasingly rare.

—Frank Graff

Frank Graff is a producer/reporter with UNC-TV, focusing on North Carolina Science Now, a weekly science series that airs Wednesdays, beginning in August 2013, as part of North Carolina Now on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog! 

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