The Baltimore Checkerspot butterfly, named for the state's founding Calvert family, has dwindled to just a handful of places, mostly in Western Maryland. Experts worry that the butterfly, once fairly common, may disappear entirely from the state.
Pockets of dedicated butterfly lovers, though, are trying to slow or even reverse the decline by breeding the species in captivity. One such nursery is in a tent in back of an old maintenance shed at Black Hill Regional Park in Montgomery County.
"Here's where the larvae are," said Barbara Kreiley, pointing out tiny caterpillars clinging to the stem of a white turtlehead plant inside the tent. The crawlers are recently hatched and still green, not yet displaying their distinctive orange-and-black markings. "My little babies — see them?"
From a single caterpillar-infested plant collected from the wild last year, Kreiley, a retired nurse, and four other volunteers reared about 250 hatchlings to adulthood. About a month ago, they released them as butterflies, in spots primed to be suitable habitat for the seemingly picky creatures. Since then, patches the women recognize as butterfly eggs have been spied on the undersides of leaves at the release sites, and they have been waiting like expectant parents for them to hatch.
Meanwhile, behind the old maintenance shed, they're already working to step up production for next year, tending to nearly 20 white turtlehead plants inside the tent on which butterflies have laid eggs. Many of the plants have the beginnings of silky "tents" in their tops, spun by newly hatched caterpillars as they feed on the leaves.
Kreiley said it's "awesome, just awesome" how well the group's initial effort has gone, but acknowledges that the real test is yet to come — can the butterflies they released flourish in the wild?
On that score, the record is not encouraging. Others, including the Maryland Zoo in Baltimore, have tried captive breeding and given up after failing to see their "colonies" take hold and sustain themselves year after year. Ruth Eisenhour, a teacher at the Harford Glen Environmental Education Center in Bel Air, said she's had some success raising and releasing the butterflies in Harford County, but she's only been doing it for three years.
The Baltimore Checkerspot is still seen across much of eastern North America, more commonly in northern states and Canada. But it's increasingly rare in the southern portion of its range, and in Maryland experts say the colorful little butterfly — long on the watch list — is increasingly in peril of vanishing altogether. It's among 37 species of butterflies now considered rare, threatened or endangered in the state. Five are officially listed as extirpated — no longer seen.
"We're definitely losing the butterfly in the state," said Pat Durkin, a retired journalist who's dedicated the past 15 years of her life to protecting and restoring the species known to entomologists as Euphydryas phaeton. Once seen in 15 counties, the butterfly is now found in perhaps five.
The butterfly has a special meaning for this state, as it's reputedly named for the first Lord Baltimore, George Calvert, who sponsored the first English colony in Southern Maryland and whose family crest also displays orange and black.
Because of that connection, the state's entomology society persuaded the General Assembly in 1973 to name the Baltimore Checkerspot Maryland's official state insect. It was still seen across much of the state at the time, but by the early 1990s had begun a rapid decline.
Experts aren't entirely sure why the butterfly is fading out, but say the most likely factor is the loss of the wet meadows it frequents, and in particular the decline of white turtleheads, a wetland plant that only grows in such settings. The Checkerspot seeks out turtleheads as "host" plants for laying its eggs.
"Some of the sites it had been found on historically were on private lands, and the properties were just developed," said Jennifer Fry, an ecologist with the Maryland Department of Natural Resources' natural heritage program. "The wetland wasn't there anymore — there were now housing developments."
Climate change also could be playing a role in the butterfly's westward shift in Maryland, Fry suggested. The most known populations are in relatively sparsely developed — and cooler — Garrett County.
But the white turtleheads that are the key to its survival are in short supply these days.
The plants, a member of the snapdragon family with white, sometimes pinkish flowers, are bitter to taste. Baltimore Checkerspot caterpillars pick up that unpleasant flavor as they feed on the leaves, according to M. Deane Bowers, an entomologist at the University of Colorado. That evidently prompts predators to leave them alone.
Unfortunately, deer like the taste of turtleheads as well, and have consumed whole stands of the plants, possibly wiping out Checkerspot caterpillars in the process.
The caterpillars themselves, though, may be to blame for some population crashes. Bowers said they have voracious appetites and if numerous enough can chew their way through their food supply — especially if it's limited.