Summer 2004

Restoring the Butterfly Tapestry

Many rare butterflies could thrive again in
restored habitats — they just need help finding them

By Doug Taron

On a beautiful summer afternoon in July of 2002, I was driving back to Chicago after visiting a couple of beautiful fen remnants in east-central Wisconsin with a colleague. The fruits of our labor — six egg-filled female swamp metalmark butterflies — now rested in a beer cooler sitting beside me, on their way, we hoped, to become the nucleus of a restored population at Bluff Spring Fen near Elgin, Illinois.

The swamp metalmark hadn't been recorded at Bluff Spring Fen since 1939, and the species disappeared from Illinois entirely in the mid-1980s. As I crossed the state line into Illinois, I suddenly had the sobering and exhilarating realization that the state's entire population was sitting on my passenger seat.

That summer and the next, our team of scientists from the Peggy Notebaert Nature Museum collected fertile eggs from the female metalmarks, raised them, and transferred more than 100 larvae to Bluff Spring Fen. It's a little like sending your kids off to college for the first time.

Using a small brush, Doug Taron releases larvae into restored habitat (in this case, Aphrodite fritillary larvae at Glacial Park). Inset, a larva is shown on the brush tip. Photos by Marla Garrison.

Such assisted reintroductions, or translocations, are an important part of butterfly conservation. Studies by researchers such as Ron Panzer at Northeastern Illinois University show that some butterflies, termed remnant-reliant species, require intact habitats like prairies and wetlands. But data from the Illinois Butterfly Monitoring Network suggest that remnant-reliant species do not spontaneously reappear, even after careful management improves a site's conditions to the point that it again becomes suitable habitat.

While it seems that rare butterflies won't automatically flock to a restored site as though to a dinner bell, translocations, closely integrated with a well-executed land management plan, physically place them in the few places they can still survive. As ecological restoration brings back more of these places in Chicago Wilderness, butterfly restoration can be expected to thrive as well.

Front and side views of the swamp metalmark butterfly (top); metalmark larva (below). Photos by Susan Borkin.

In northwest Indiana, Paul Labus of The Nature Conservancy has been reestablishing populations of the Karner blue at the Ivanhoe Dune and Swale Preserve near Hammond. This tiny blue butterfly, which is on the federal endangered species list, requires open oak woodlands with sandy soil where wild lupine grows, the only plant its caterpillars can eat.

In 1996, the butterfly disappeared from the site as a result of two separate wildfires. In both 2001 and 2002, wild-caught females from the Indiana Dunes National Lakeshore were induced to lay eggs in the laboratory. Over 1,000 adults have been released on the site. The butterfly appears to be thriving and even spreading, possibly benefiting from reduced shade and healthier host plant populations that follow a fire. Some have even turned up on a second site a half-mile away.

Karner blue butterflies (top, male; bottom, female). Photo of male by Thomas A. Meyer; photo of female by Paul Labus.

The Peggy Notebaert Nature Museum's butterfly restoration program began in 2001, when we received a BP Leader Award of $100,000 to support the project. Since then, we have bred three species for restoration purposes. In addition to the metalmark, the Nature Museum placed about 50 silver-bordered fritillary caterpillars on violets at the Fermi National Accelerator Laboratory in late summer 2002. Though they do not appear to have survived the unfavorable winter that followed, we gained valuable experience in rearing this species in the laboratory, producing over 500 chrysalides in three successive generations. In October 2003, we placed 75 Aphrodite fritillary larvae at Glacial Park in McHenry County. By July of 2004, we should know if they have established the beginnings of a population.

Regal fritillary. Photo by Patricia Armstrong.

As for the swamp metalmarks, in July of 2003, we spotted the first adults. Numbers remain precariously small — we have seen but two adults to date. But we remain hopeful that they represent the beginnings of a long-term presence of this butterfly at the fen. Already in early spring of 2004, I am finding larvae in the rosettes of the swamp thistle that they feed on. It's a small sign that this ornate butterfly could again sail over fens across Chicago Wilderness.

Doug Taron is curator of biology at the Peggy Notebaert Nature Museum in Chicago and one of the founders of the Butterfly Monitoring Network in northeastern Illinois. He is a steward at Bluff Spring Fen Nature Preserve in Elgin.

Related Articles:

Swamp Metalmark Returns to Bluff Spring Fen

Aphrodite Fritilllary: Goddess of Butterflies

Gems of the Bug World

Making Friends with Butterflies