Lights out?

BAN LOMTUAN, THAILAND - Preecha Jiabyu used to take tourists on a rowboat to see the banks of the Mae Klong River aglow with thousands of fireflies.

These days, all he sees are the fluorescent lights of hotels, restaurants and highway overpasses. He now has to row a good 2 miles to see trees lit up with the magical creatures of his younger days.

"The firefly populations have dropped 70 percent, in the past three years," said Preecha, 58. "It's sad. They were a symbol of our city."

Yet another much-loved species imperiled by humankind? The evidence is entirely anecdotal, but there are anecdotes galore.

From backyards in Tennessee to riverbanks in Southeast Asia, researchers said they have seen fireflies -- also called glowworms or lightning bugs -- dwindling in number.

No single factor is blamed, but researchers in the United States and Europe mostly cite urban sprawl and industrial pollution that destroy insect habitat. The spread of artificial lights also could be a culprit, disrupting the intricate mating behavior that depends on a male winning over a female with its flashing backside.

"It is quite clear they are declining," said Stefan Ineichen, a researcher who studies fireflies in Switzerland.

Too many flood lights

There are about 2,000 species and researchers are constantly discovering new ones.

Fredric Vencl, a researcher at Stonybrook University, discovered a new species two years ago only to learn its mountain habitat in Panama was threatened by logging.

Lynn Faust spent a decade researching fireflies on her 40-acre farm in Tennessee, but gave up on one species because she stopped seeing them.

"I know of populations that have disappeared on my farm because of development and light pollution," Faust said. "It's these McMansions with their floodlights. One house has 32 lights. Why do you need so many lights?"

The fate of the insects drew more than 100 entomologists and biologists to Thailand's northern city of Chiang Mai last week for an international symposium. On Friday, they traveled to Ban Lomtuan, outside of Bangkok, to see the synchronous firefly Pteroptyx malaccae -- known for its pulsating flashing that looks like Christmas lights.

Many species have never been studied, leaving scientists in the dark about the potential threats and the meaning of their Morse code-like flashes that signal everything from love to danger.

The problem is, a nocturnal insect as small as a human fingertip can't be tagged and tracked like bears or even butterflies, and counting is difficult when some females spend most of their time on the ground or don't flash.

And the firefly's adult life span of just one to three weeks makes counting even harder.

But with little money and manpower to study the problem, experts are turning to volunteers. The Citizen Science Firefly Survey in Boston, which started this year, is encouraging enthusiasts to report changes in their neighborhood firefly populations.

Scientists acknowledge the urgency to assess fireflies may not match that of polar bears or Siberian tigers. But they insist fireflies are a "canary in a coal mine" in terms of understanding the health of an ecosystem.

Preecha couldn't agree more. He has seen the pristine river of his childhood become polluted and fish populations disappear. Now, he fears fireflies are next.