VOA慢速英语:同时发光的萤火虫

Crowds will gather in two forests in the United States in coming weeks to see light shows created by a rare species of firefly.

These fireflies have the ability to light up with others at the same time. The insects stay lit for 10 seconds, go dark for about a minute, then shine bright again.

"You're standing in a dark forest and suddenly there is a brilliance of little lights everywhere," said Tara Cornelisse. She spoke to the Reuters news agency. Cornelisse is a scientist with the Center for Biological Diversity in Portland, Oregon.

Scientists are not sure why some fireflies light up at the exact same time. But they believe that it helps attract reproductive partners during the weeks-long mating season.

Three years ago, Cornelisse traveled to the Pennsylvania Firefly Festival in the Allegheny National Forest to see the light show.

Cornelisse said of the experience, "It's like the Milky Way flashes on and then off. You hear people gasp ‘Ohhhh!'"

Synchronous fireflies are found only in a handful of places in the United States. In addition to the Allegheny National Forest, they light up the night sky in Tennessee at the Great Smoky Mountains National Park and Oak Ridge Wildlife Management Area. Others are found in South Carolina's Congaree National Park, and around Cajon Bonito Creek in Arizona.

This list of places comes from the website Firefly.org.

Other synchronous firefly species are found in Southeast Asia.

Starting life underground

Fireflies live for two years under Earth's surface as larvae. They feed on worms and snails, creatures that live mainly underground, notes Sara Lewis. She wrote a book called "Silent Sparks: The Wondrous World of Fireflies." She is a professor at Tufts University in Massachusetts.

Once the fireflies are adults, they rise up above the ground to spend a few weeks finding a partner, mating and making eggs before they die, said Lewis.

She added that researchers "know very little about why ... (the fireflies) developed this behavior that makes them an eco-tourist attraction."

Loss of fireflies

The Great Smoky Mountains National Park is making final preparations for the crowds of people coming to see its light show.

Park service officials found a way to limit the number of vehicles entering the park. They set up a lottery for the 1,800 parking spaces on the grounds. More than 28,000 people entered the competition. People from over 40 states and as far away as Taiwan won the chance to leave their car near the park's entrance in Townsend, Tennessee.

Tickets sold out in 12 hours for a 2019 light show in the Allegheny forest on June 22, said Peggy Butler, the event's organizer. The park is a short drive from the small town of Tionesta, home to fewer than 500 people. This year, officials are trying to limit the crowd to 800.

Organizers said many visitors who come to the firefly events are from Asia.

Butler said, "They want to see the fireflies they remember but don't see any more in places like China and Japan, where human impact and human encroachment on the environment has led to the loss of the firefly."

There are 2,000 different kinds of fireflies worldwide, lighting up the night sky in yellow, green or blue. In Asia, synchronous males remain in mangrove trees, timing their flashes to interest flying females.

The situation is generally the opposite in North America, where it is the males who are flying around flashing and the females are sitting on the ground, Lewis said.

The downside to firefly light shows is the likelihood that without crowd controls and limits, humans will destroy the very thing that drew them there in the first place.

"There is a danger in just the presence of those people," Lewis said. "You could actually wipe out the population that is so attractive."

I'm Bryan Lynn.

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