February 27, 2006
LONG LIVE THE MONARCHS!
The struggles and triumphs of our favorite butterflies
JOHN J. MILLER
For more than a week, the skies over the highlands of central Mexico were almost cloudless. But on January 12, a storm blew in from the Pacific Ocean, dumping rain and snow everywhere. Even after the bad weather had moved off, temperatures hovered around the freezing point and often dipped below it. For the monarch butterflies that spend the winter in the region, the cumulative effect was devastating. Researchers believe that half a billion of them — about 75 percent of the population — were wiped out. It was a biological disaster.
That was four years ago. Last winter the numbers looked even worse, reflecting the fewest monarchs on record. This time the culprit wasn’t a storm in Mexico, but a wet and cool summer in the upper Midwest, the monarch’s primary breeding range. Once again, the cruel forces of nature seemed to conspire against the species. “I would say the monarch is in a precarious situation now,” said Lincoln Brower, America’s dean of monarch experts who is also a biologist at Sweet Briar College in Virginia. From him and others, there was talk of “permanent devastation” to the species.
Today, however, the monarchs have made a comeback — and I couldn’t be happier. You see, I’ve grown up with these bugs, spending a portion of nearly every summer of my life in northern Michigan at the cottage that my grandparents built back in the 1960s. There’s plenty to do Up North (as we natives call the area), and one of the things I’ve always done is to seek out monarch caterpillars and then raise them into butterflies. As Vladimir Nabokov once wrote, “I have often dreamt of a long and exciting career as an obscure curator of Lepidoptera in a great museum.” I know exactly what he was talking about.
Nabokov was fascinated by a certain breed of blue butterfly in South America. By my reckoning, however, nothing can compare to the orange-and-black monarchs of North America. They possess everything you expect from a butterfly: sparkling color, lively fluttering, and a fondness for flowers. Yet there’s something else about the monarch that makes it like no other creature: With a four-inch wingspan, it embarks on a stunning migration to Mexico each year, often covering more than 2,000 miles in a trek that is a wonder of the natural world.
A typical member of the Lepidoptera family is likely to spend the winter hibernating in a chrysalis or a cocoon. But the monarchs I raise each summer fly all the way from Michigan to Michoacan, a Mexican state a bit west of Mexico City. It was once calculated that a 6-foot-tall person would have to walk around the planet eleven times in order to perform a comparable feat. So while the march of the penguins may be impressive, I prefer the flight of the butterflies.
I’ve informed my wife — not a bug lover — that at some point in our lives she can expect to take a trip with me to Mexico to see the butterflies in the winter. Although they will have departed from points all over the eastern United States and Canada, millions of them will settle in just a handful of Mexican colonies, where they perch for months on oyamel fir trees. The butterflies cluster together so closely that they bend tree limbs, taking up such little space that the precise location of their wintering grounds wasn’t even discovered until 1975, by the amateur naturalist Kenneth C. Brugger. It has been observed that when the monarchs open their wings on warm days, the effect is like looking at a stained-glass window in the middle of a mountain forest.
Although these butterflies look fragile and weak, they are in fact resilient and, as we have seen, capable of dramatic comebacks. For them, cycles of crash and boom are just a way of life. This year’s winter population, according to initial estimates by Monarch Watch, a group based at the University of Kansas, probably fills 12 to 17 acres. That’s about average — and this year, average is anything but routine. A year ago, the Mexican colonies totaled only 5 acres. “I thought we were looking at a real decline,” says Karen Oberhauser, a University of Minnesota biologist. “Now I’m cautiously optimistic.”
Even so, monarchs remain severely threatened. In Mexico, illegal logging — much of it done by poor farmers in need of firewood — has reduced the butterflies’ range. The World Wildlife Fund claims that, between 1971 and 1999, monarchs lost about 40 percent of their winter habitat. The species is not listed as endangered because there are separate populations in California that don’t travel south of the border, but the great Mexican migrants might be only a few harsh seasons away from catastrophe. “They could slip to a vanishingly small number,” warns Chip Taylor of the University of Kansas.
To think that one day monarchs may become rare — or even gone — makes me sick to my stomach. And I’m hardly the only one. Monarchs are perhaps the most popular insect in the United States, or at least a close second behind ladybugs. Because of this, they have become a kind of poster child for environmentalists. The Sierra Club has published full-color glossy books about them.
But while many greens have done a good job building awareness about the plight of the monarchs, others have not hesitated to exploit them for entirely different purposes. Global-warming doomsayers, for example, have tried to use the monarch to make an emotional appeal about the dangers of climate change. Even worse have been the exploitations of the anti-biotech groups, which in 1999 hailed a study that seemed to show that the pollen from genetically modified corn, when dusted on the milkweed plants that monarch caterpillars consume, acts as an insecticide. This finding attracted enormous attention around the world, causing many people to question the value of an increasingly common food source. Even though there are no monarchs in England except for the human kind, Prince Charles felt compelled to chime in: “If [biotech] plants can do this to butterflies, what damage might they cause to other species?”
As it turned out, the original study was so contrived as to have virtually no real-world applicability: It merely showed that force-feeding the pollen to young caterpillars in a lab would kill them. This didn’t even come close to replicating what would happen in the wild. “Traditional pesticides are actually a much bigger threat than biotech corn ever will be,” says John Foster, an entomologist at the University of Nebraska. “A lot more monarchs die on the grills of 18-wheelers than they do from farmers who plant biotech crops.”
The real problems that monarchs face are sadly more serious than biotech corn, especially in Mexico. “It’s a classic tragedy-of-the-commons scenario,” says R. J. Smith of the Competitive Enterprise Institute. As a legacy of the Mexican Revolution, the areas inhabited by monarchs theoretically belong to the Mexican people. “Without clear lines of ownership or property rights, everybody feels like they have a right to live off the land,” says Smith. Eco-tourism is a source of some local revenue, but not enough, and logging remains too economically attractive for many poor villagers to resist. There have been attempts to establish compensation schemes — using American philanthropic dollars to turn the tree-cutters into tree-huggers — but so far these haven’t reversed the region’s deforestation. Perhaps a few market principles would: Mexican officials might sell key tracts of land to private investors, who could then manage their own monarch habitats while charging admissions fees for visitors.
In the United States, both government and private efforts are helping somewhat. The North Carolina Department of Transportation, for example, has set aside more than a dozen sites along roadways for monarch habitat. Other highway departments could make a big difference merely by changing their mowing practices, as roadsides provide an ideal habitat for both milkweeds and the monarchs that rely on them. Monarch Watch encourages landowners to grow patches of milkweed known as “monarch waystations,” while groups such as the Monarch Larva Monitoring Project and Journey North are teaching adults and schoolchildren about how to pitch in.
It’s clear that even the smallest efforts can matter. In the outdoors, a female monarch can lay more than 300 eggs, but most of the caterpillars that hatch never become butterflies — perhaps 95 percent fall victim to spiders or other predators. The simple practice of removing these caterpillars from the outdoors, raising them in captivity, and then releasing them after they’ve transformed into butterflies — an excellent activity for kids, as I’m finding with my own — may help preserve the species.
Chaos theory has taught us that tiny changes in early conditions can produce incredible differences in long-term results. It’s called the butterfly effect.