It’s not easy to see the orange and black spotted regal fritillary butterfly if you live in the Eastern U.S. It used to be common across much of the country, and is still found in the Midwest. But it’s all but disappeared in the East, its once vast habitat developed, divided and degraded.
A 2007 federal report found that this now rare butterfly’s “decline in the East was so rapid that in many states the regal fritillary had disappeared before it could be listed” as endangered.
But the species has survived at one unusual refuge, and for a few days every summer hundreds of people join guided tours to get a glimpse.
On a recent July morning, a tour group gathers at Fort Indiantown Gap, a National Guard training center in central Pennsylvania. They pile into their cars and caravan out to a grassy field. Wildlife biologist Mark Swartz leads them as police direct traffic.
“It takes a lot of coordination,” he says. “It occasionally breaks down, and that’s when we have problems.”
On this day, in fact, Swartz is a bit rattled because the Air Force apparently didn’t get the memo. Suddenly he’s interrupted by loud noises. “There—they’re shooting,” he says. “That’s a .50 caliber machine gun.”
Swartz scrambles to have the training flights re-routed. Once the planes are safely out of the way, he hops out of his car and leads the tour through a field.
A military base may seem a surprising haven for wildlife. It makes sense when you consider that the base has largely kept away people and development. But Swartz says the activities that do take place here actually help create the kind of meadows where the regal fritillary thrives.
“Tanks and other military vehicles… go in and tear up the ground,” he says. “They tear up what would have been trees and turn it back into a grassland.”
That landscape supports the plants the butterflies feed on to grow.
As the tour group of some 200 strolls around it doesn’t take long to spot a butterfly flapping by. A line of people quickly grab cameras and snap away.
This is Michael Bean’s second time on the tour. He drove up from Washington D.C. for the day, just to see the regals.
“It’s heart-warming to see as many people as there are here today,” says Bean. “That’s quite remarkable to see a rare insect.”
About 100 miles from the base, in Philadelphia, the Academy of Natural Sciences of Drexel University houses one of the oldest insect collections in North America. It includes many specimens and notes from the prominent 19th century naturalist Titian Peale, who was able to find the regal fritillary in the city.
The butterfly’s decline in recent decades fits into a broader pattern of biodiversity loss, driven by factors like habitat destruction, invasive species, and climate change. A stark United Nations report earlier this year found that about a million animal and plant species are threatened with extinction.
The Academy’s Entomology Curator Jon Gelhaus says that pollinators like bees and butterflies are especially important to humans, because they play a critical role in food production.
“We’re not just protecting nature for some kind of ideal intrinsic value,” he says. “These things actually do things for us.”
Researchers in Pennsylvania are working to introduce the regal fritillary to new habitats, hoping they can expand its range beyond the military base.