Constable: Rare dragonfly calls the suburbs home

With its dazzling, jewel-green eyes, exoskeletal-thin body and two sets of translucent wings, the Hine's emerald dragonfly looks almost too prehistoric to be at home in today's suburbs. Even with 300 million years of evolution behind it, the rare dragonfly remains dangerously close to extinction and might not be here at all without an extraordinary effort to keep the majestic creature alive in the suburbs.

“It was thought to be extinct in the early 1960s,” says Kris Lah, endangered species biologist with the U.S. Fish & Wildlife Service office in Barrington. Today, there are tiny populations of the Hine's emerald dragonfly at DuPage County's Waterfall Glen Forest Preserve near Argonne National Laboratory, the Lockport Prairie Nature Preserve, just west of the Des Plaines River in Will County and spots in southern Cook County. Lah says only 80 to 320 adult members of the species are thought to exist in Illinois. The world's largest Hine's emerald dragonfly population lives in Door County, Wis., with much smaller settlements in the Upper Peninsula of Michigan, Missouri and Ontario, Canada.

“The Hine's emerald is very complicated because it has a long life cycle,” says project director Daniel Soluk, a professor at the University of South Dakota who has championed the effort to save the insect in the 20 years since it landed on the federal endangered species list. A Hine's emerald dragonfly spends its first four or five years in the larval stage, requiring a very specific habitat of clean and cool spring- or seep-fed streamlets that are dry for part of each year and are underlaid by dolomitic, limestone-like rock.

“When I started working on this species, it was all farmland,” Soluk says of the suitable habitat found in the Des Plaines River valley. “It isn't anymore.”

Originally known colloquially as the Ohio emerald, the insect already had died out in Ohio, Indiana and Alabama when officials began the efforts to save it in Illinois. “It's taken a while,” says Soluk, who says the Illinois populations remain tiny, fragile and vulnerable.

As protection from birds, fish and other predators, the mobile dragonfly larvae seek refuge in crayfish burrows, where they survive winters and dry months. They feed on small aquatic organisms, including the larvae of midges and mosquitoes. In the wild, about 1 in 100 eggs survives long enough to produce an adult.

Last week, Soluk and his team released three adult dragonflies that were “captive-reared” in labs. Plans call for as many as 50 to be released in Illinois from now through next summer, Soluk says. Lah says the goal is to create a stable population of 1,500 dragonflies in the state.

“If we're going to have a population in Illinois, it's essential that we do this,” Lah says, noting the government has had success in similar conservation efforts with butterflies. “This is the first time an effort has been done for the dragonfly.”

Those efforts include cooperation from all three counties' forest preserve districts and the Illinois State Toll Highway Authority, which not only protected the dragonfly habitat as I-355 was extended but also funded surveys of the population and paid for a genetic analysis, Lah says.

“Conservation efforts are helping the species,” says Soluk, who says society will be richer for saving this dragonfly.

“Dragonflies were around a long time before the dinosaurs,” he says, explaining how fossils of dragonflies with 28-inch wingspans aren't all that different from the modern version one-tenth that size.

“They are supreme aerial predators. They've perfected it to an incredible degree,” Soluk says, explaining how flight experts study the way adult dragonflies zip through the air picking off mosquitoes, midges and even deer flies.

“There's more genetic diversity in Chicago. We think of the small Chicago population as being really, really important,” Soluk says, explaining how that diversity makes the insects less vulnerable to a catastrophic event. “They've been in Chicago probably since the glaciers retreated. We hope to bring the population up to a level where you don't have to worry about them not being there one year.”