Four Wings and a Prayer (8 page)

“I’ve probably handled a hundred thousand monarch butterflies in my lifetime and still see them as magic,” Brower told me months after we had left Mexico, when he was showing me around his laboratory at Sweet Briar College. “I think of them as magical bottles of wine: you can pour it all out, and when you go back, it’s full again. There is no end to the questions you can ask.”

The lab was a mess, with books and papers and pipettes and pinned collections of lepidoptera, one made when Brower was a high school student in New Jersey, piled high on tables. Five red Mylar balloons that said “I Love You” were stuck to the ceiling, their white grosgrain ribbons suspended in the air like jet trails. In one corner of the room were three steel freezers, the size and style of those you might see in a college cafeteria. I opened one. It was stocked, from floor to ceiling, with plastic bags full of dead monarchs, their signature orange and black markings just visible beneath the hoar of frost. There were ten thousand of them, dating back to 1976.

“You never know when they’ll come in handy,” Brower said, though he didn’t say for what. He did explain that he had only recently dismantled his lab at the University of Florida and had the contents shipped to Virginia. He was just getting reorganized. He had not really retired, he said, only relocated. (His new wife, Linda Fink, was a biology professor at Sweet Briar and his sometime collaborator.) The “I Love
You” balloons were for an experiment he would be doing the next day on butterfly navigation.

Until recently Brower had shied away from navigation and orientation, concentrating instead on questions that had to do, in one way or another, with chemical ecology. He was an experimental biologist; he had an abiding belief in the necessity, and the beauty, of the scientific method.

“Science is like a language. You have to have a grammar and you have to have rules. It’s a universal language because anyone can do it, no matter what his or her native tongue is. What we get from a lot of amateurs is ‘I saw five butterflies down at the baseball park on Sunday at five o’clock.’ If they went out there every year at the same time and watched what was going on and then published the data, it would be valuable. If you compare a really carefully done experiment with some half-assed little anecdotal report and give them equal weight, that, to me, is not acceptable science.”

Brower was getting agitated. Here he was, a biologist, a professor, and yet also the object of more enmity than he, or his station, deserved. And it went way back, to the discovery of the overwintering sites themselves, when the Canadian biologist Fred Urquhart had published hints as to the overwintering sites’ whereabouts in
National Geographic,
and Brower, hoping to do some research there himself, had written to ask for more specific directions. When he was rebuffed, he gave the
National Geographic
article to Bill Calvert, and Calvert figured out where the sites were.

“It was January 1977. We were in the forest trying to measure the temperature above the ground. We had thermometers strung at different heights. It was very cold. One of our guides had lit a fire. By chance, Urquhart was there
that day, too. I went up to him and stuck out my hand. He refused it and said, ‘How did you get here?’ Shortly afterward, Urquhart wrote an article accusing me of smoking out the butterflies. Then scores of people who read it wrote nasty letters to the president of Amherst College, where I was teaching, accusing me of killing butterflies. It was very divisive.” Brower was cast as a villain among his natural constituents, the amateur lepidopterists.

Urquhart’s followers, who numbered in the hundreds, had been tagging monarchs in Canada and the United States, hoping to learn where the butterflies went in the winter and by which routes. To them Brower was an interloper; to him, they were unsystematic. In his language, that meant they were gnats, bothersome but inconsequential. Gracious though he was, courtly though he could be, Lincoln Brower could also be short with anyone who didn’t think the way he did. He wasn’t out to make friends. He was after the truth, and when he found it, he wanted to let others know. If the truth demanded action, then surely they would want to hear that.

Truth used to be wings pinned to foamcore, properly named. That was when Lincoln Brower was a boy in western New Jersey, roaming the farmland his family owned, and the surrounding woods. He was a collector, a boy who took pride in finding and identifying and displaying. There was an old German entomologist in the neighborhood who took him collecting in the Great Swamp. When the man died, Brower inherited his business, collecting and selling cocoons. He was a boy, making a couple of hundred dollars a year. His parents had been through the Depression. There was a lesson here: you could make a life and a living doing what you loved to do.

A
S A GRADUATE STUDENT
at Yale in the 1950s, Brower found himself raising butterflies for a project that his first wife, Jane, was working on: the first controlled studies of mimicry in animal coloring, looking at bird predation on butterflies. The theory was that monarchs were distasteful, even poisonous, to certain birds because their larvae fed on milkweed. Their unpalatability moreover protected not only them but other, similarly colored butterflies such as viceroys, which were not thought to have their own inherent chemical defense. Birds, which rely on sight more than on smell when seeking prey, would see any one of these other orange-and-black butterflies, assume it was toxic, and leave it alone. (“Sometime just pick up a monarch butterfly and pinch it. It will regurgitate. Put a drop on your tongue and taste it; it’s really bitter,” Lincoln told me.) So Brower raised viceroys, which look a lot like monarchs but are smaller; and monarchs, which are the largest of the black-and-orange butterflies and whose caterpillars feed on milkweed, which makes the cardiac glycosides that are toxic to certain bird species; and tiger swallowtails, which are yellow and black and nontoxic.

The study was a success. Jane Brower was able to show that monarchs were indeed unpalatable. By feeding them to blue jays under controlled conditions, she demonstrated not only that the birds vomited when they ate monarchs reared on particularly toxic milkweed varieties, but that once they did, they learned not to eat them or butterflies that looked like them. It was a learned response.

“Sure enough,” Lincoln said, “the monarch butterflies were toxic, and the jays wouldn’t eat them or the viceroys.
But they did eat the palatable butterflies, the swallowtails. But birds that had had no experience with monarch butterflies ate them. And got sick.”

That was the expected, and hoped-for, result. But to the Browers’ surprise, the experiment revealed something else as well: different species of milkweed contain different concentrations of the noxious chemical cardiac glycoside, which in lower doses may be unpleasant to the birds but does not cause them to throw up or die. “If we hadn’t thought the tuberosa milkweed was more toxic than the other varieties and had fed the monarchs the nontoxic kind, the experiment would not have worked, and we might have given up,” Brower explained. Instead, it set him on a different path altogether, away from his graduate studies in larval cannibalism, through a study of chemical defense in monarchs, to, ultimately, the development of a procedure called cardenolide fingerprinting, which enables scientists to tell where each butterfly comes from by determining what species of milkweed it fed on as a caterpillar.

But in the 1950s, the discovery that different milkweed varieties had different toxicities led Brower to another observation—that there was a kind of protection within the species itself that operated like Batesian mimicry (wherein nontoxic species colored almost identically to toxic ones are able to use their coloring to deter predators, which can’t tell which is which). Monarchs that were not especially unpalatable were being protected by the jays’ conditioning through eating more toxic monarchs—monarchs that caused “retching, vomiting, excessive bill-wiping, alternate fluffing and flattening of feathers, erratic movements, head and wing jerking, partial eye closure, and a generally sick appearance.” In the annals of natural history, it was ground-breaking research.

Not all birds were equally or even adversely affected by cardiac glycosides, however. In Mexico, Bill Calvert had noticed that black-backed orioles and grosbeaks did not shy away from eating monarchs. Indeed, he estimated that in one colony alone, they were killing about thirty-four thousand butterflies a day—or more than a million in that single season.

Predator and prey—that, of course, is how nature works. But it’s not hard to see how a scientist might move from an uninflected observation to something more emphatic and urgent—how Brower could easily assimilate this number, one million, and model what it would be if the forests were thinned and the butterflies had less tree cover, or what it might be if they were simply more exposed and vulnerable to attack. Then it would be not just nature running its course but nature with a tipped hand. Clearly the butterflies were at risk if the forest lost its density. Brower was coming to understand that. From there it was not much of a stretch to go from being a research scientist to being an environmental advocate. In a way, the facts demanded it. If the monarchs were going to be protected, then the forest had to be, as well.

“My whole career, up until we confronted the deforestation of the overwintering sites in Mexico, was pursuing questions purely because they were interesting and because there was a historical basis for the research,” Brower said the morning we went to his lab. “Even the question ‘How do monarchs survive the winter in Mexico?’ is a pretty basic biological question. Right now my research is bouncing back and forth between what I can do to show we can’t cut these trees and what interesting biological questions I can address.”

Later he said something more telling: “I grew up on a large farm in New Jersey. Every place I collected butterflies as a boy has now been turned into a housing development. I
had a wonderful trail through the woods where I’d collect underwing moths. I’d paint the trees with sugar, which would attract the moths. Have you ever seen one? They are gorgeous. That land was all sold off and turned into a golf course. One day not long afterward I was out playing golf and I spotted a few white marks from the sugar trail on trees that had been cut down. That just did it. I never played golf again.”

In the years since, Brower has made it a point of pride to testify against land development and developers, to take positions on conservation issues across the country and abroad, to marshal the information he has garnered by doing science to push particular political points of view. The science may be neutral, but the scientist is not.

S
O BROWER WAS
not pleased, the way everyone else seemed to be, with the 1997 bumper crop of monarchs. Amid all the caviling voices on Monarch Watch and the other monarch migration tracking site, Journey North, his was noticeably flat. When monarchs reached Texas in March, much to the excitement of people who lived in Dallas and Uvalde and Johnson City, Brower cautioned, “That’s too early. They’ll be in the Midwest in April. I don’t think the milkweed will be up yet.” His point was that the monarchs had to be supported by habitat. They had to eat, or else they would starve. And that was not all. In all the years he had been doing research, he had noticed that monarchs kept to a regular schedule. In Florida, for instance, “they came the last week of March and the first week of April every year, like clockwork.” Butterflies that had jumped the calendar worried him.

As respected as Brower was, his worry was largely disregarded. He was like those market analysts who see the Dow cresting 12,000 and say “Correction, correction”—words that no one wants to hear except people selling short. But in biology, no one was selling short, so Lincoln Brower was simply ignored. “Lincoln was just being Lincoln,” more than one of the monarch watchers told me, with a “can we get back to the party now?” kind of impatience. In their estimation he was by nature an alarmist.

To some extent this attitude was justified. Although Professor Brower had been the first research scientist (along with the natural historian and lepidopterist Bob Pyle) to make the distinction between an endangered species, which the monarch was not, and an endangered phenomenon, which the monarch migration appeared to be, and though that distinction was accepted and formed the basis for a lot of other research and advocacy, he had squandered a certain amount of goodwill the year before, in a six-hundred-word
New York Times
op-ed piece. Written with the poet Homero Aridjis and entitled “Twilight of the Monarchs,” the essay was published just days after an unseasonable snowstorm in the Neovolcanic Belt. Although winter temperatures in the overwintering sites typically hover around freezing, it rarely snows there. That was one of the reasons, it was surmised, that the butterflies migrated there in the first place. Freezing temperatures could be deadly. Rain could be deadly. Snow most certainly would be deadly.

Lincoln Brower and his colleagues, in fact, had done the definitive studies on the monarch’s (lack of) tolerance for low temperatures. As Brower described it, “I wanted to determine the temperature butterflies freeze at, so I inserted
a thermal probe into their bodies, put them into a vial, put the vial in solution, and dropped the temperature. When the water in the butterfly freezes, it releases the heat of crystallization. You know that’s the freezing point. I did that for several hundred and found that the freezing point is minus eight degrees centigrade. Then I wet the butterflies and did the same thing. They could only go down to one degree centigrade before they froze.”