By Ilene Dube

In its 17th year, the Butterfly Conservatory at the American Museum of Natural History joins such long-running family traditions as visits to the skating rink in Rockefeller Center and the model boat races in Central Park.

After passing the large dinosaur skeletons in the lobby, visitors go through a series of double doors to the Butterfly Conservatory, or vivarium, a 1,200 square foot freestanding transparent structure where they are surrounded by up to 500 fluttering, iridescent lepidopterans feeding on tropical nectars from flowers and lush green vegetation. There may be polar vortices outside, but here in the Butterfly Conservatory, it’s a tropical 80 degrees.

Powerful halide lamps shine from the ceiling, simulating the sunlight that streams through a rainforest. The tropical temperatures are maintained through the use of the double doors, which also ensure no errant butterflies make their way into the IMAX Theater or the squid and the whale diorama.

Every day, it seems, we read in the news about the ways in which butterflies are important harbingers of environmental change. So upon entering the Butterfly Conservatory the first question I ask Hazel Davies, Associate Director of Living Exhibits, is how the worldwide butterfly population can be sustained when they are shipped to New York in the dead of winter, destined for a life indoors.

“All of our butterflies are raised on farms,” explains Davies. “They’re not taken from the wild.” It’s like Christmas tree farming: As long as you farm butterflies, you’ll have a steady supply.

She leads me to a rack of pupae that have just arrived from Florida farms. They look like racks of iridescent green earrings, except as I look closer I see they are not perfect pairs; everyone is different. And they are alive! Each has spun silk from which it hangs.

A brief review of butterfly metamorphosis: The butterfly starts as an egg and hatches into a caterpillar. After eating a lot of leaves and gaining weight, the caterpillar sheds its skin and enters the pupal phase. The pupa, also known as the chrysalis, neither eats nor moves (like those “earrings”). Soon legs make their way through, then wings, and an adult butterfly emerges.

Below the pupae are what look to be papery rocks. These are Luna Moth cocoons—12 moth species have been shipped from Florida.

“The pupa is the best stage at which to ship them,” says Davies, who also works with spiders, lizards, snakes and frogs in other exhibits. In addition to the farms in Florida, the pupae at the Butterfly Conservatory are raised in Costa Rica, Ecuador, Kenya, Thailand, Malaysia and Australia. “The caterpillar is an eating machine and we’d never have enough food for them in the city,” says Davies. “When they pupate, the farms pack and ship them.” The pupae are packed in cotton wool and tissue paper for cushioning. They breathe through spiricles, or breathing holes, but don’t need air exchange, food or water.

“Caterpillars pee and poop,” I overhear a docent telling a group of visitors. So do butterflies, I learn.

Heat packs help to keep the pupae warm. If they were in the wild, the pupae would attach themselves to the underside of a leaf or a twig. The boxes are stamped “live” and “keep warm.” “FedEx knows not to leave them on the truck,” says Davies.

There’s a lot of paperwork for the pupae to get into the country legally. They must go through U.S. Customs and Fish and Wildlife and get a permit from the U.S. Department of Agriculture. “The USDA is concerned about the butterflies getting out and becoming a plant pest, releasing pheromones and mating, when there may be no host plants on which to lay their eggs,” says Davies. One can imagine the headlines: “Invasion of the Butterfly Pupae.”

Butterflies are host-specific, when it comes to laying their eggs. Monarchs, for example, can only lay eggs on milkweed. The main host plant for the Eastern Black Swallowtail is Queen Anne’s Lace.

Precautions need to be taken so the pupae don’t bring in a parasite. Wasps and flies can lay eggs in the chrysalis, and these need to be isolated and frozen so they don’t get released into the environment, says Davies.

She assures me that the farms do their best to protect the pupae so they arrive alive and disease free. “They have been practicing shipping to exhibits like this for 25 years,” she says. Still, three to five percent of the pupae will not make it into adult butterflies. Yet in the wild, only five to ten percent would become butterflies—the others might be eaten as eggs, or the caterpillars might become food for songbirds. They may catch a disease, suffer from drought or have a parasitic fly. Raised on a butterfly farm, they are protected from life’s harsh realities.

OK, so the pupae arrive, become butterflies and live out their lives here. Some may live a week to ten days, others may live six weeks to two months. Shipments come every week, and there are 130 different species at any time.

One of the farms raising the pupae is El Bosque Nuevo in Guanacaste, Costa Rica, where land is reforested and dedicated to conservation and protection of native species. Exporting farmed butterflies actually helps raise the funds needed to preserve the land. The operation also provides work for Costa Ricans.

Butterflies flapping their wings overhead cast fluttering shadows on all below. One is perched on a dracaena—it is pure black with pink spots, and it suddenly takes flight. The most important sense for butterflies is smell. Sensors on their antennae are highly attuned to odors. They can also taste—taste buds are at the end of the tongue, and the female can also taste with sensory structures on her feet.

They communicate through chemical cues, and a few species communicate with sound. Remember, in the insect world it’s all about reproduction, so their communication is love talk.

Yes, butterflies do mate while in the conservatory, but since there are no host plants for them to lay eggs on, they do not reproduce. So how do they do it? If you see two adult butterflies with abdomens linked tail to tail, they’re doing it. The male grasps the female and deposits a sperm packet, which fertilizes the female’s eggs. Butterflies can and do fly while mating, but prefer to avoid moving unless disturbed.

The Order Lepidoptera includes butterflies and moths, and here in the conservatory we see Cecropia, Polyphemus moths from Florida and Atlas moths—the largest moths in the world from Southeast Asia.

Although there are exceptions to the distinctions that separate moths from butterflies, in general the butterfly has straight antenna with a club at the end, whereas the moth’s antenna has filaments that come to a point. Moths have chunkier fuzzier bodies and rest with their wings open, while butterflies bring their wings together overhead while taking a break.

It’s a myth that butterflies are beautifully colored and moths are a dull brown. The Madagascar Sunset Moth is beautifully iridescent, and there are dull brown butterflies. The biggest difference is that moths produce a cocoon like a sleeping bag around the chrysalis. Eric Carle’s The Very Hungry Caterpillar is wrong! I overhear a docent announce this. In Carle’s beloved children’s classic, the hungry caterpillar spins a cocoon but only moths do this.

Visitors are discouraged from touching butterflies, both in the conservatory and outside. Butterfly wings are covered with tiny scales that look like powder—these are what give the butterfly its coloration and pattern. When the butterfly loses scales it can lose its ability to fly. If a butterfly gets stuck on, say, the ceiling, Davies will use a feather to coax it down for a drink.

Bright colors and distinctive wing patterns can, however, be advantageous. The caterpillars of many species feed on toxic plants, and throughout their lives their tissue is poisonous to predators. As adults, these butterflies make no attempt to hide themselves; instead, their bright, warning coloration is like a neon sign. A bird that eats one of these toxic butterflies remembers the experience and avoids repeating it. Other butterflies mimic the colors of toxic butterflies to defend themselves from predators.

From the exhibition, a visitor learns that butterfly fossils, such as the 40 million-year-old Prodryas persephone, are remarkably similar to modern day forms. Butterflies developed during the Cretaceous Period—the “Age of Flowering Plants”—65 to 135 million years ago, when dinosaurs roamed the Earth.

Because butterflies are sensitive to environmental change, scientists look to them as indicators of the health of the environment. Human activities, from logging and agriculture to urban expansion and industry, are the biggest causes of habitat loss. Pesticides and herbicides don’t discriminate against butterflies and their food plants. Climate change is altering the distribution of plants, including plants that feed butterflies.

Butterfly caterpillars are voracious plant-eaters, yet they contribute to plant survival. Arthropods consume 20 percent of the earth’s vegetation each year. By chewing and digesting leaves, caterpillars excrete frass (take that, Scrabble players) and cycle waste into nutrition available for other plants and living organisms.

Adult butterflies consume flower nectar for carbs, proteins, salts and enzymes through a tube resembling a drinking straw called a proboscis.

In turn, butterflies and caterpillars are food for insects, songbirds, mice, lizards, turtles and spiders. Mice feed on Monarchs at their overwintering sites in Mexico. Vladimir Nabokov was a serious lepidopterist. He volunteered at AMNH and conducted research, publishing a paper on American butterflies. In 1951 he hiked 10,000 feet in the Colorado Rockies and captured the first female Lycaeides argyrognomon sublivens—his notes found their way into Lolita.

The butterflies in the conservatory are welcoming—they check out visitors, landing on a shoulder or a head. They do not bite, but they may get stuck in your clothes, which is why you go through another set of double doors on leaving, where mirrors help you see if one has hitched a ride in the folds of your clothing.

After the tropical heat, it is refreshing to get outside for a walk in the cold air. More than 150 butterfly species are found in the New York-New Jersey-Connecticut region and maybe, if you time your visit right, you’ll spot a Summer Azure, Zabulon Skipper, American Lady, Common Sootywing or Eastern Comma fluttering through Central Park.

The Butterfly Conservatory at the American Museum of Natural History, Eighth Avenue at 81st Street, is open daily, 10AM to 5:45PM through May 25. Suggested admission is $22 adults, $17 students/seniors, $12.50 children. www.amnh.org