"There is an overwhelming abundance of lightning bugs this year! Walked down Spring Grove Road last night and the trees were just sparkling. Thousands! I am 52 years old and have never seen anything like it."

Celia Fauth, who lives in the Hamilton Park neighborhood of Lancaster, dispatched that e-mail to me a week ago.

I went outside that very night in the Bridgeport area and she was right. Fireflies — or lightning bugs or glowworms, if you prefer — were setting the night on fire. Way up in the treetops even. I don't think you could have walked to the church yard across the way without intercepting one.

The girls soon had an insect box glowing like a Lite-Brite set.

Others have noticed it, too. "My backyard looks like LA from the air," chimed in a mesmerized co-worker.

"Yes, yes, yes, there's a lot more this year than the last few years," says 73-year-old Lititz naturalist Al Spoo. "There's not quite as many as when I was a kid, but there's a lot this year."

Not only are lightning bugs exploding earlier than usual. Their breakout in hefty numbers comes on the heels of several years of stories warning that the beloved bugs of summer are disappearing from the landscape.

What gives?

Greg Hoover, Extension entomologist in the Penn State Department of Entomology, thinks the most likely reason for the swarms of fireflies this year in eastern Pennsylvania is a combination of ample moisture in the soil and unusually warm temperatures.

Moist soil means lots of immature insects, slugs, snails, worms and the like, the main diet of firefly larva. The larva live in the ground and under leaves for up to two years before taking to the air as adults with their beacons to multiply.

And die. Those adult lightning bugs you're watching only live two to three weeks before dying.

Hoover says it's been much drier in most of the rest of the state and firefly numbers aren't as high as here.

Also, the warm weather experienced in April has terrestrial and aquatic insects in general in Pennsylvania emerging two weeks ahead of schedule.

Sven Spichiger, entomology program manager for the state Department of Agriculture, agrees spurts of warmth in April seem to have intensified hatches of many insects this year.

"Normally, lightning bug populations trickle out and build over time," he notes.

Elevated firefly populations are occurring in Florida as well, reports Marc Branham, an assistant professor at the University of Florida and one of the country's few firefly researchers.

But Branham says he's slightly puzzled because eastern Pennsylvania had a harsh winter and Florida has had a dry spring, two factors that normally repress firefly populations.

Fireflies are one of the most beloved insects. It's the Pennsylvania state insect and who among us doesn't have a fond memory of filling jars with the sparkling bugs and falling asleep to their twinkling?

But we know surprisingly little about them.

That's because they're not insect pests. Research dollars go toward bugs that harm the stuff we eat, notes Hoover.

We do know that fireflies are actually not flies but beetles. There are about 35 species of fireflies in Pennsylvania. There are fireflies that are active at dusk and others after it's really dark.

Each species has a different flash pattern. For example, the males of hotinus marginellus, a common species in these parts, have a hopping flight pattern close to the ground and give off a flash every 3.5 seconds.

The purpose of that flashing, called bioluminescence, is mostly to attract mates, though it is also used as a scare tactic for defense.

Females watch the males emit their light, recognize their own species and select a mate, flashing back to come hither.

Often it's the males that can flash the longest that are selected. Duration matters.

Depending on species, fireflies emit light that is orange, green, yellow and even blue. Even firefly eggs glow.

Fireflies are found as far west as the middle of Kansas.

Because they are stuidied so little, when scientists and people like you and me started noticing that fireflies seemed to be getting less numerous each summer, no one could tell for sure.

"While everybody agrees there seemed to be many more fireflies back when they were a kid, there aren't any hard and fast numbers," says Branham.

One result of this was the launch of Firefly Watch in 2007, an effort by the Museum of Science in Boston and scientists to get everyday people to volunteer in scientific research.

What you do is watch your backyard or favorite field for about 10 minutes one evening a week during the summer and report online what you see.

If interested, go to www.mos.org/fireflywatch . So far, citizen scientists from 38 states have participated.

The recent fireworks notwithstanding, it does appear fireflies are having a tougher time of it these days.

Pesticides and herbicides applied to lawns and fields, mowing, habitat fragmentation, outside lighting — fireflies have to be able to see flashes of potential mates — all may be bringing down numbers.

Branham says he's certain some species of fireflies in North America have already vanished. On the other hand, over the last 10 years, he's discovered new, unnamed species on campuses in Gainesville, Fla., and at Ohio State University in Columbus, Ohio.

"I would just hate to see a time where fireflies weren't part of our culture and part of our childhood," he says.

So go outside, urges Lisa Sanchez, a naturalist at Lancaster County Central Park.

"It just seemed to happen all of a sudden one night — boom there they were, everywhere. And it was beautiful.

"Go outside and look. It's right there. Just open your door and take a look at it."

acrable@lnpnews.com