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Where Did They Go? Environmental Threats Shrink the Numbers of Illinois' Beloved State Insect

Monarch Butterfly
Adele Hodde
Illinois Department of Natural Resources

Urbana resident Alex Wild kept an eye out for monarch butterflies last year. He was alarmed by what he saw. Or rather, what he didn’t see.

“I saw two the entire season,” says Wild, a biologist and photographer who specializes in taking close-up pictures of insects. “That was it — and I was looking for them.”

In Tuscola, about 35 miles south of Champaign, butterfly enthusiasts Kirby and Cindy Pringle also had trouble finding monarchs. “We saw only a handful,” Kirby says. “We could probably count them on our fingers and toes.”

And Decatur resident Susan Martin says she doesn’t see nearly as many monarchs as she did when she was growing up. “When I see one, I’m like, ‘Ooh! There’s a monarch!’ — because it’s rare,” she says.

In 1974-75, when Martin was a third-grader at Dennis School in Decatur, her class led a drive to designate the monarch butterfly as the official state insect of Illinois. Martin (whose name at the time was McReynolds) and her classmates went to the state Capitol and persuaded lawmakers to crown the monarch with this special designation.

“We didn’t have a state insect,” she recalls. “So it was like, ‘Hey, let’s vote on something!’ And we picked the monarch butterfly. All the kids, we loved butterflies, and the monarch was so pretty.”

Bright orange with black and white markings, the monarch is one of the most popular insects. “The monarch really catches people’s imaginations in a way that no other species of butterfly seems to — in part, because it’s big and pretty,” says Doug Taron, curator of biology and vice president of conservation and research at the Peggy Notebaert Nature Museum in Chicago.

But scientists are worried about the fate of the species. In the last few years, the number of monarchs has plummeted in Illinois and other parts of North America.

Taron runs the Illinois Butterfly Monitoring Network, which sends about 100 trained volunteers walking on assigned routes through places, such as forest preserves, each summer. They identify and count every butterfly they see within 20 feet of themselves.

Numbers aren’t available yet for 2013, but the volunteers spotted only 2.05 monarch butterflies per hour during their walks in 2012. In most previous years, they saw at least twice as many. The peak year was 1996, when monitors counted 14 monarchs an hour.

The monarch population has gone up and down over the years, but scientists say the current decline is more severe. “They’re a population that is really prone to boom-and-bust cycles,” Wild says, “which makes it really hard to figure out if they’re having any kind of long-term problems. But this current decline is really scary. It is much more severe than anything we’ve previously seen.”

  Scientists say several factors may be causing the population drop, but one of the key problems is a scarcity of milkweed in the Midwest. The number of milkweeds in the region fell 58 percent from 1999 to 2010, at the same time that the monarch population dropped 81 percent, according to a study in the journal Insect Conservation and Diversity.

Milkweeds are essential to the monarch because they’re the only plants where female monarchs will lay their eggs. A caterpillar emerges a few days later, feeding on the milkweed for about two weeks until it is ready to form its chrysalis.

Most milkweeds — various wildflowers in the genus Asclepias, including 19 species in Illinois — contain toxic chemicals called cardenolides. When most animals ingest these chemicals, the toxins can cause vomiting and irregular heartbeats. But monarch caterpillars eat it up, incorporating it into their bodies and using it as a defense. Those milkweed toxins stay in their systems as they go through metamorphosis inside the chrysalis. After 10 days to two weeks, an adult butterfly emerges — a creature that’s beautiful, but poisonous to many potential predators.

Over the course of a summer, monarchs go through several generations. Each generation lives a few weeks and then dies off after reproducing — except for the last generation of the year. Those monarchs live as long as eight months. This is the brood that flies south for the winter, escaping the freezing temperatures that would kill it.

Back when monarchs were more common, big clouds fluttered through Illinois each September.

“I’d go out my door and there would be thousands of them,” says the Nature Conservancy’s Karl Gnaedinger, recalling his childhood in the 1960s and ’70s in Lake County.

In the 1990s, Kirby Pringle and his wife, Cindy, lived in a rural part of southern Champaign County, with half an acre of restored prairie on their land. “We would just see hundreds come in and land on our trees,” Kirby says. “You would just see clumps of them on the trees. They come in the late afternoon and early evening, and then they just settle in. Once they land, they’re very still and their wings are folded up.”

“It’s like watching a butterfly ballet, just the sheer beauty of them,” his wife says.

But until 1975, scientists didn’t know where the monarchs were going when they flew south.

The man who solved the mystery was Kenneth Brugger, a textile consultant from Kenosha, Wisconsin. On January 2, 1975, Brugger and his wife, Catalina, went hiking through a forest of Oyamel firs in the mountains 80 miles southwest of Mexico City. Suddenly, they noticed the trees were covered with monarchs.

The area’s indigenous people, the Purepecha, called the butterflies the “souls of the departed” because they usually arrived during the Day of the Dead celebration from October 31 to November 2. “They were part of the landscape of the Day of the Dead, when you could see them flitting around the graveyards,” Gloria Tavera, director of the Monarch Butterfly Biosphere Reserve, recently told the Associated Press. 

Scientists still don’t know how the monarchs know to fly to that specific spot in Mexico where previous generations have gone.

Monarch Butterfly
Credit Adele Hodde / Illinois Department of Natural Resources
Illinois Department of Natural Resources
Monarch Butterfly

  “These butterflies have never been there before,” says Michael Toliver, a biology professor at Eureka College in Woodford County, who specializes in butterflies. “And yet, they always go to the same place. So, how do they get there? What sort of genetic program are they using to find that particular area?”

If monarchs ever become extinct, scientists would lose all hope of ever solving this mystery, and that alone would be a great loss to the world, Toliver says. The world would also lose a pollinator, but Toliver says it’s hard to say how much any particular plant species would suffer without pollination help from monarchs. 

The cool temperatures in Mexico’s mountains allow the monarchs to lower their metabolic rates. They rest in dense clusters on the trees from mid-November to mid-March, conserving the fat they’ve stored up for the return flight.

This past winter, the monarchs covered only 1.65 acres of the Mexican forest — the smallest number ever recorded, marking a third-straight year of steep decline. That figure was down 83 percent from 2010-11. Back in 1996-97, the monarchs covered 52 acres of forest — 31 times as much space as they occupied this past winter.

The monarchs have lost some of their winter habitat to logging. But in February, The New York Times reported: “The Mexican government has proved successful over the past five years at halting most of the large-scale illegal logging that was long seen as the biggest threat to the monarch. But smaller logging continues.”

After the spring equinox, monarchs fly north, stopping first in Gulf Coast states, where they lay eggs on milkweeds, producing the year’s first generation of new butterflies. Several generations are born, fly north, lay eggs and die — until that final, longer-living brood is born in the upper Midwest and starts the journey south.


Monarch Migration

Climate change and weather conditions may be affecting the monarchs. “With the droughts and the excessive rains coming at the wrong times, the last two years have been very bad for butterflies,” says Gnaedinger, who manages the Indian Boundary Prairies nature preserve in southern Cook County.

But more than anything else, the people fighting to save the monarch are worried about the decline of milkweeds. Many point to the widespread use of genetically modified crops and other agriculture practices to explain why milkweeds are becoming scarce.

Since 1996, most farmers have switched to planting genetically modified corn and soybeans, which are engineered so they won’t be killed by the herbicide glyphosate. That allows farmers to use that herbicide to kill more of the weeds in their fields.

“The down side is that plants that don’t have that resistance get nailed, and that includes a lot of milkweed,” says Toliver, the butterfly expert at Eureka College.

“The Midwest has basically been converted into this death zone for anything,” bug photographer Alex Wild says. “The monarch is just one species of many that doesn’t live here anymore.”

But Aaron Hager, a weed science expert with the University of Illinois Extension, questions how much these recent agricultural practices have affected milkweeds, which are perennials. “Perennials don’t thrive very well under aggressive tillage,” he says. “They just can’t become established.” Milkweed was always more common on roadsides, pastures and prairie patches than it was in row-crop fields, he says.

“I’ve never seen much milkweed in fields,” says David Wessel, a farmer in Chandlerville, about 50 miles northwest of Springfield. And in the years since Wessel began using genetically engineered crops in some of his fields, he hasn’t noticed much change in how much milkweed grows between the rows.

But even if milkweed always seemed scarce in fields with row crops, research shows those plants provided an especially valuable habitat for monarchs, according to University of Kansas insect ecologist Orley “Chip” Taylor, who runs an organization called Monarch Watch.

Another factor is the increasing amount of land devoted to farming row crops — and the shrinking amount of land where milkweeds can grow.

The number of harvested farm acres in Illinois grew from 20.1 million in 1950 to 22.6 million in 1990, according to state and federal data. Since then, it has inched up to 22.9 million acres.

“Now they’ve planted almost right up to the edge of the road, because they want to get more corn,” says Pat Wemstrom, who lives in the countryside near Mount Carroll, in northwest Illinois. “So they took away a lot of habitat for birds and butterflies.”

Pat and her husband, Chuck, are retired Chicago schoolteachers who write a column for the Freeport Journal-Standard, often urging their neighbors to think more about the environment.

“We’re creating deserts,” Chuck says. “They don’t even rotate the corn. They used to do corn, beans and something else. Now they just do corn and spray it more.” Back in 1950, corn and soybeans covered 60 percent of the state’s farmland, with the rest devoted to wheat, oats and hay. Today, corn and soybeans cover 93 percent.

Illinois farmers are also putting less land into the federal Conversation Reserve Program, which pays them to set aside land for conservation. The state’s acreage in the program dropped 8.6 percent between 2007 and 2013. Or put another way, 93,702 acres that were set aside for conservation purposes are now being farmed.

Wessel, the Chandlerville farmer, says he always waits until August before mowing the roadside strips of land next to his fields. “It’s for wildlife,” he explains. “It’s just to give them all a chance to nest and to rear their young and lay eggs. I’ve tried to be a good steward of the land and a conservationist.”

Wessel, who heads the Illinois Farm Bureau’s team for conservation and natural resources, says he encourages other farmers to wait before mowing roadsides. “For the most part, I think the farmers are trying to do what they can,” he says. “They understand that habitat has dwindled over the years.”

But John Wilker, program manager for the Illinois Department of Natural Resources, notes, “The average land-owning farmer worries about keeping their ditches clean.” Wilker, who grew up on a farm outside Lockport, says, “I know how important it is for them to keep up with the Joneses. You start not mowing your ditches, and your neighbors start complaining.”

State officials and groups like Monarch Watch are urging people to help out the monarch by planting milkweeds. 

“We encourage landowners to plant native plants, including the larval host for the monarch — milkweeds — in their landscaping,” Wilker says. “We encourage those in the rural areas not to mow roadside ditches until after the larvae have matured, usually the end of August.”

“We can all make a difference even by having a little prairie patch in our yards,” says Kirby Pringle of Tuscola, who made a 20-minute documentary, Plight of the Monarch, with his wife. “If enough people did that, you could make up for a big loss in habitat.”

But Chuck Wemstrom is skeptical that such efforts will have much effect. “Until the farmers give back part of the ground for butterflies, it’s not going to make any difference what I do outside my front door,” he says.

And people who live in some towns and cities may get into trouble with local authorities for growing milkweed.

Last year, a Chicago inspector fined Kathy Cummings for allowing milkweed to grow in her prairie-style front yard in the Humboldt Park neighborhood. Ironically, her garden had previously won a landscaping award from the city. When Cummings contested the ticket, she recalls, “The judge said, ‘In my experience, that is a weed.’ He was pointing to milkweed. And for that, he fined me $640.”

Cummings is suing the city, challenging its weed ordinance as vague and overly broad. City officials have said the law is constitutional. Cummings says she wants to provide a habitat for monarch butterflies in her yard, and she can’t understand why the city is trying to stop her.

Someone in Mexico has some advice for this situation. When a reporter for McClatchy Newspapers visited Mexico’s monarch butterfly reserve in April, a member of the local agriculture commune told a visitor from the U.S.: “We want you to stop killing the milkweed.”

Eureka College professor Michael Toliver says everyone should do their part to save the monarch. “Butterflies are kind of the canary in the coal mine here,” he says. “They’re saying to us: ‘If a number of our species are in trouble, think of how many species that no one even thinks about are in trouble.’”

Robert Loerzel is a Chicago-based free-lance writer.

Illinois Issues, July/August 2014

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