It's a Very Good Summer for Lightning Bugs in the Washington Area

Fireflies, a.k.a. lightning bugs, are neither flies nor bugs. They are beetles.
Fireflies, a.k.a. lightning bugs, are neither flies nor bugs. They are beetles. (By Don Salvatore -- Associated Press)
By David A. Fahrenthold
Washington Post Staff Writer
Saturday, July 11, 2009

This is that strange, sweet part of summer when life stops for a beetle's behind.

On a June night in Bethesda, a woman blast-e-mailed her neighborhood: "Go outside RIGHT NOW. Look into the dark." At a park in Arlington, a man clicked one flash from a penlight and waited for an insect to signal back.

This is firefly season in Washington, the best and brightest in several years. Scientists say a wet spring has made a lightning-bug-friendly region even more so, and hordes of the insects are now spending the last days of their lives floating over lawns and blinking in treetops.

In the daytime, most fireflies -- there are about 2,000 species of them worldwide, 200 in the United States -- look like a second cousin to the junebug. But at night, chemical reactions produce a glowstick light from their abdomens, each tiny bug worth about 1/40th of a candle.

This spectacle holds even more magic if you know what they're saying.

"Then the whole world of fireflies opens up to you," said Sara M. Lewis, a professor who studies the family Lampyridae ("shining ones") at Tufts University outside Boston. There is seduction and rejection, codes and code-breaking, mating and eating alive. "You can watch the dialogue," she said.

Across the country, scientists worry that firefly numbers have been driven down by lawn pesticides and sprawling concrete. Also, chemical companies have paid a per-bug bounty to get the chemicals in their tails, which are used in scientific research.

Washington has always been a good place to see fireflies. The numbers, which had seemed down, have rebounded this year -- possibly because wetter soil is more friendly to both firefly larvae and the things they eat.

"We were a little worried," said Michael J. Raupp, a professor of entomology at the University of Maryland, "but they seem to be back in force."

They provided such a show of strength in the Bannockburn neighborhood of Bethesda that a departing dinner guest pulled Jillaine Smith out of her house, to see a scene that looked like Christmas.

"They were everywhere," Smith said. "We just stood there and stared for a long while, because what is there to say?"

Then she went inside and e-mailed the neighborhood listserv: "MILLIONS of lightning bugs. The meadow is swarming with them. Go. Now."

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