WHITEHOUSE, Ohio -- First, she flinched. Then Caitlin Myers covered her face with her hands and squealed. The 2-year-old didn't know which way to turn.

Butterflies with blue, orange, yellow and white wings fluttered and swooped around her.

"She loves them," said her mom, Chris Myers. "They're fine as long as they don't come too close."

It's nearly impossible to avoid erratic movements of the monarchs, longwings and swallowtails skipping about the Butterfly House, an indoor garden filled with tropical plants and hundreds of butterflies.

"These guys travel around like drunken sailors on a 10-day binge," said Gilbert Martinez, who visits the exhibit in suburban Toledo at least twice a month. "That's part of their beauty."

Whether it's the butterflies' spectacular colors or their close interaction with visitors, these walk-through exhibits have become big crowd pleasers. There are at least 100 nationwide, with many at zoos and museums where visitors are sometimes charged an extra fee -- usually $2 to $3 -- to walk among the winged insects, according to the International Association of Butterfly Exhibitions.

"People love going to the zoo, but you can't get in the cage with the lions," said Mike Weissmann, a consultant who helps set up butterfly exhibits around the country.

Admissions at the Huntsville Botanical Garden in Alabama doubled last year after it opened a butterfly house and children's garden.

Some stand-alone

exhibits are open year-round in popular tourist spots:

The Butterfly Palace in Branson, Mo., offers an alternative to country music and shopping.

Florida is home to nearly a dozen butterfly exhibits, including the Key West Butterfly and Nature Conservancy.

The Niagara Parks Butterfly Conservatory in Canada is just 10 minutes from Niagara Falls and features more than 2,000 tropical butterflies.

There are even more outdoor butterfly gardens open in warm weather months. Zoos in Oakland, New York (Bronx Zoo), St. Paul, Minn., and Oklahoma City are among a growing number with butterfly gardens.

The Smithsonian's outdoor garden is just steps outside the National Museum of Natural History along the National Mall in Washington, D.C. The museum also is building an enclosed butterfly exhibit that will open in November. The American Museum of Natural History in New York has an annual indoor exhibit that opens each October.

Indoor butterfly houses got their start in Europe during the 1970s. The first one came to the United States in 1988 when Butterfly World opened in Coconut Creek, Fla., north of Miami.

It has grown to include a butterfly breeding center along with hummingbird and lorikeet exhibits where visitors can feed a cup of nectar to the colorful lorikeet parrots.

About 250,000 people visit each year, said founder Ron Boender.

As many as 10,000 butterflies are on display each day. "We have an entire farm that breeds exotic species of butterflies," Boender said.

Most butterflies on display at other exhibits come from farms in Costa Rica, Malaysia and the Philippines.

Boender doesn't think the expanding number of butterfly attractions has been entirely positive.

"Everybody sees it as a fast buck," he said. "I don't mind if they're first-class exhibits. There are some good ones. There are a lot of poor ones."

Weissmann, who is consulting on about a dozen new exhibits this year, said zoos are looking beyond the traditional crowd-pleasers -- such as elephants and polar bears -- to educate visitors about habitat and species conservation.

"A huge portion of animals are underrepresented in zoos," he said. "Butterflies are great ambassadors to teach about the rain forest."