The Monarch’s Uncertain Future

Monarch butterfly, courtesy of Didier Descouens, Wikimedia Commons

The first monarch of the season arrived Saturday at the Butterfly House, at the Paul Smith’s College VIC.

Monarch Watch, a network of students, teachers, volunteers and researchers who study Danaus plexippus, reports that the migratory butterfly’s population has declined since 1996. That’s when Midwestern farmers began using herbicide-resistant seed to grow corn, soybeans and canola.

The genetically modified crops are unharmed as aerial spraying kills weeds and other plants along the edges, including milkweed, the monarch caterpillar’s only food.

A 1999 study published in the journal Nature indicates that crops spliced with genes from Bt (Bacillus thuringiensis—the same stuff some Adirondack towns pour into streams to kill blackfly larvae) may also be hurting monarch caterpillars. In a Cornell University laboratory test, caterpillars that ate milkweed covered in Bt-modified pollen died while those that ingested pollen from unmodified corn were unharmed.

Although 77 percent of the Adirondack Park is wooded, it plays a role as a haven for the butterfly. A handful of midsize dairy, potato and apple farms are as close as the region comes to big agriculture, and patches of milkweed grow alongside roadsides, hayfields and small farms. Since monarchs follow several different paths to and from their wintering ground in Mexico, natural landscapes like this will be key to the species’s longterm viability.

Still, we who live in the Adirondacks are not disconnected from the problem. It has become almost impossible in the United States to go a day without using genetically modified crops, either as government-mandated ethanol in our gas tanks, or as oil and sweeteners in processed foods, or as the feed that fattens the cows that become our hamburgers.

In the Midwest, volunteers plant milkweed in backyards in an attempt to restore egg-laying way stations along the monarch’s migratory routes. The Adirondacks has more forest than field, but we too can help the species by judicious mowing of roadsides. This area has never been a milkweed stronghold, so it’s not imperative that we go out and plant new stands. In fact, I regret cultivating milkweed in my small yard. In an attempt to create my own monarch nursery (for my viewing pleasure more than for the benefit of the butterflies) I planted milkweed a few years back. It quickly took over and I am still pulling shoots.

There are thick stands of milkweed just down the street, where neighborhood kids collect caterpillars to take home to watch the metamorphosis into chrysalis, then butterfly. Rearing caterpillars in an artificial habitat requires close attention to moisture, light, food and other variables. If you do have a lot of yard space, you could set part of it aside for milkweed and watch the transformation unfold outdoors.

According to Monarch Watch founder Chip Taylor, all of North America, from Mexico to Canada, would benefit from a plan to manage the in-between spaces created by development and agriculture. These edges support pollinators and other wildlife that are sustained by the seeds, fruits and foliage that result. “In effect,” Taylor says, “we need a new conservation ethic, one dealing with edges and marginal areas that addresses the changes of the recent past and anticipates those of the future.”

For daily updates on what’s going on in the world of butterflies and moths, check out Butterfly List Digest. To sign up for Monarch Watch’s daily e-mail discussion on monarch activity, click here.

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