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Life on the Wing

Children are so sensitive to the natural world, sometimes all it takes is a single moment to alter the course of their lives.

Lincoln Brower is now 83 years old.  But he still remembers with perfect clarity a time one day when he was six and growing up in Northwest New Jersey.  He was lying on his stomach in the grass, near where his parents were playing tennis.

“In those days, the lawns were full of an array of weeds and wild plants and caterpillars galore,” Brower recalls at his home in the Blue Ridge Mountains of Virginia.  “And this little copper butterfly appeared on a clover blossom, sipping nectar.  And I got really interested in that butterfly, probably because I was lying down really close to it. And I could see this gorgeous pattern on the wings.”

On each of the fire-colored wings, there were four or five black marks arrayed almost like a code, or a secret language.

“It just struck me like a bolt of lightning, and I still remember it,” Brower said.  “And actually my first scientific paper was on that butterfly.”

During a distinguished academic career that took him from Princeton to Yale to Oxford and beyond, Brower cracked the code of the butterflies. He discovered not only what genes controlled the patterns on those coppery wings, but also the connection between the diets of Monarch butterflies and their ability to survive predators by making themselves toxic to birds.

Brower, now a professor of biology at Sweet Briar College in Virginia, is one of the world’s leading experts on monarchs.  It is a remarkable species that evolved a beautiful poison.  Monarch caterpillars eat only milkweed plants, whose white sap makes the butterflies toxic to birds.  Brower’s research helped to confirm that bluejays, for example, that are attracted to the colorful orange, black, and white butterflies, and eat them, vomit because of the toxins from the milkweed. So birds quickly associate the beauty of monarchs with sickness, and so avoid them.

Over a half-century of study, Brower wrestled with the puzzle of the insect’s genetic memory.  Monarchs are the only insect that migrate every year thousands of miles from farmland in the Upper Midwest to a single forest of fir trees in the mountains of Mexico.

“They are flying back, to Mexico, to the same areas – and in many cases, the very same trees – that their ancestors were on a generation previously,” Brower said.  “So how do they find their way back there, never having been back there before?  There has to be a genetic memory.”

Thirteen years ago, Brower correctly predicted in an Orion magazine article that a then-new agricultural herbicide, Round-Up, used in combination with genetically modified corn, would contribute to a catastrophic collapse of the monarch population.  Since then, Brower and other scientists argue, the herbicide has starved to death more than 90 percent of the monarchs by killing the milkweed plants that monarchs depend on. RoundUp allows genetically modified crops to live, but kills all the other plants and wildflowers in and around the farm fields.  This loss imperils variety of insects and animals that depend on wildflowers, and impoverishes biodiversity.

“So basically you are converting this rich ecosystem and you are converting it into a monoculture,” Brower said. “I will show you some pictures where Roundup is used, and it’s like a desert – it’s a sterile environment. There’s not a weed, there is not a blade of grass, there is not a thing growing in those fields or around the edges of those fields, when they used to be chock full of nectar sources and milkweeds.”

In his final years, Lincoln Brower is on a mission to save the butterfly that inspired his career. He is working with environmental groups, including the Center for Biological Diversity, that have petitioned the U.S. Fish and Wildlife Service to classify the monarch as a threatened species.

He wants his butterflies protected, so that – even when he is gone -- future generations of children can gaze in wonder at the secrets written on their wings.

Tom Pelton, a national award-winning environmental journalist, has hosted "The Environment in Focus" since 2007. He also works as director of communications for the Environmental Integrity Project, a non-profit organization dedicated to holding polluters and governments accountable to protect public health. From 1997 until 2008, he was a journalist for The Baltimore Sun, where he was twice named one of the best environmental reporters in America by the Society of Environmental Journalists.