Pioneers and government agencies tried every imaginable method of control. They prayed for deliverance, organized bounty systems, conscripted able-bodied men into “grasshopper armies,” and provided food aid for starving communities. Farmers tried to burn and beat the invaders—or, failing this, they turned to drowning and plowing the eggs or crushing and poisoning the hatching locusts. Elaborate horse-drawn devices were invented to destroy locusts, and the most desperate farmers resorted to using dynamite to blast the egg beds of the insects. This approach surely decimated local pockets of the pest and provided a hearty sense of revenge, but pulverizing thousands of acres with explosives was hardly a viable strategy. And so, as courageous and creative as these methods were, the locusts kept coming.
The swarms continued to pummel America’s heartland into the 1880s, moving and settling with the caprice of tornadoes. Their devastation was like that of a living wildfire, consuming fifty tons of vegetation per day to fuel a typical swarm. Finally, in the 1890s, to the relief of a beleaguered nation, the locust outbreaks subsided. But such remissions had occurred before, only to have the locusts return with a fury. When a small swarm was reported in Manitoba in 1902 people wondered if another period of devastation was at hand. The specter of an outbreak loomed and there were still no reliable methods to defend the land.
Nobody could have guessed that this would be the last swarm of locusts to be seen in North America. Suddenly—and mysteriously—the Rocky Mountain locust had disappeared. For a decade nobody noticed, as more urgent matters of a world at war occupied the nation. Later, a few state entomologists remarked on the absence of their former nemesis. But soon another ecological and economic crisis captured the attention of the country. The Dust Bowl of the 1930s displaced both soil and people. This disaster was aggravated by horrific outbreaks of grasshoppers—renewing the memories of locust plagues. But the stories would eventually fade in a culture that looked to the future, rather than the past. Nine decades would pass before the Rocky Mountain locust made its next appearance. And this time it would be found in a most remarkable place.
AUGUST 1995, KNIFE POINT GLACIER, WIND RIVER RANGE, WYOMING
“Goddamn! Jeff, come check this out!” Larry cried, dropping to his knees, the frigid water soaking into his pants. Although swearing was not entirely out of character, such ebullience was unexpected—particularly given how cold and tired he must have been. Two days earlier, Larry had hiked the twenty-three miles to Indian Pass in the Wind River Range of Wyoming. The other members of the scientific team, including me, had ridden two-thirds of the way, until our horses started slipping and stumbling on the steep, wet path, after which we scrambled over the rocky trail on foot.
It was our second day on the glacier, and the previous day had been cruelly disappointing; we had found no evidence of insects in the ice. We had good reason to believe that this expedition was going to pay off: Geologists collecting ice cores from this glacier earlier in the season had heard of our work and told us they’d found what looked like rotting insects. Besides, Larry argued, after years of searching we had finally earned enough karma (his term for suffering of any sort, especially when undeserved) to score the “big one.” The previous night’s dinner of undercooked macaroni with powdered cheese had been punctuated with fewer jibes and jokes than our usual camp meals.
Larry DeBrey had been my first graduate student and had worked as my research associate for the last three years. Before coming to the University of Wyoming, he had operated his own logging company, worked highway construction, and fought forest fires. Only a few pounds heavier than I, he carried twice the weight of ropes, carabiners, ice screws, and collecting bottles that I hauled. Seeing Larry on his knees was not surprising. He’d suffered from scoliosis—and between childhood surgeries and metal rods he couldn’t bend over very well, which also explained why he preferred hiking to riding a horse. But he was not prone to outbursts of excitement; dry witticisms were his standard fare.
“Come over here. Look, they’re everywhere,” he said, waving his hand toward a boulder incongruously perched in the center of the ice flow. The glacial ice crunched under my crampons as I hurried from the edge of the moraine, where I’d been jotting notes.
“What’s everywhere?” I asked.
Before he could answer, it was my turn to drop to my hands and knees. The surface of the rotting ice was like a frozen cheese grater. In a tiny cavity, soaked in meltwater, lay a crumpled form about an inch and a half long. Its legs were missing, but the bulbous head, powerful thorax, tapered abdomen, and straight wings left no doubt that this was the body of a grasshopper—or a locust. In the intense sunlight that cuts through the thin air of 12,000 feet, the dark remains had melted out of the surrounding ice.
For five years I had waited for this. At other sites we had discovered ancient fragments that could be tentatively ascribed to the Rocky Mountain locust, and we had found intriguing deposits of modern-day grasshoppers. But we had yet to find an intact body of the locust, the definitive evidence that our quest had not been a foolhardy venture. Could these soggy bodies be the bizarre treasure that might prove to be a window into the last days of the Rocky Mountain locust?
Larry’s ruddy face split into a grin at the prospect of having struck entomological gold. He’d stuck with me through August snowstorms, lung-searing climbs, and horrifically bad advice from local guides. Scattered across the surface of the glacier, either in water-soaked pockets or just beneath the ice, were dozens of these mummified insects. The afternoon passed quickly with tedious but hopeful labor, as we gently placed the limp and sodden bodies in numbered vials. That night, as Larry brought water up from the stream and Craig and Charlie fixed dinner, I laid out a couple dozen of the better-preserved specimens under the harsh, white light of a Coleman lantern. Gently turning the limp bodies onto their sides, I finally found a male. Within seconds of lifting the first body from its watery grave, I knew that it was in the genus Melanoplus, to which the Rocky Mountain locust belonged—but the only way to be certain of the species was to examine the internal genitalia of a male. Dismembering the body would effectively destroy a rare and valuable specimen, but I had to know if we had found what we had been looking for.
I didn’t know what I was going to tell Larry if the specimen wasn’t the Rocky Mountain locust. But then, we’d grown used to disappointment, almost inured to failure. We’d come to love the hunt, the companionship, the quixotic search for buried treasure. I had no doubt that if the species was something other than the locust, Larry would pause from his well-earned meal, nod knowingly, and declare that, by God, tomorrow we’d find the bastards. And if not, then we’d go back to the yellowing reports of the early geologists and the topographic filigree of modern maps. That is, if we could garner endorsements from increasingly dubious colleagues and eke out funding from correspondingly impatient sources. But I’d begun to harbor misgivings of a different sort.
Seeking the physical remains of the once glorious Rocky Mountain locust was both thrilling and saddening. The North American continent had never seen a life form with greater fecundity. Swarms of these insects swept across the prairies, at one time reaching from southern Canada to the Mexican border and from California to Iowa. They were the leitmotif of the Great Plains, as powerful a life force as the great herds of bison. To touch a creature that had shaped the folk-tales, culture, and history of the West would be worth years of frustration. Or so I had believed.
After searching so long and hard, I began to wonder whether it was right to disturb the icy tombs secreted in the Rockies. Even if the glaciers would one day yield the remains of the locust, maybe this most magnificent of species should be allowed to rest in peace amid one of the country’s most spectacular settings. As I began to tease apart the mushy abdomen I didn’t know whether we had finally succeeded. Finding the tiny, diagnostic structures within the decomposing soft tissues was a slow and delicate process that gave me time to contemplate what I did know. I understood that I had transc
ended the bounds of science. I was coming to realize that my intention to rob the graves of this long-lost creature imposed a deep obligation, the nature of which I was only beginning to discern.
The extinction of the Rocky Mountain locust is the quintessential ecological mystery of the North American continent—a century-old homicide on a continental scale. How could an animal whose swarms numbered in the tens or hundreds of billions simply vanish within a decade? Coming to terms with this species and its lessons has meant seeking leads among the daily journals and tragic stories of the early settlers, returning to the formative years of American entomology through the lives of its most influential practitioners, and searching for new evidence in icy graves and on musty bookshelves. For fifteen years I worked on this case, sometimes for only a few days at a time, sometimes for months. It is a tale of people, egos, values, and insects colliding to generate a remarkable series of events—along with a few false leads.
A brilliant Russian entomologist, Boris Petrovich Uvarov, laid the foundation for what seemed to be the solution to the locust’s vanishing act. He showed how these insects can transmogrify into incredibly divergent forms between their solitary and migratory phases. Following on his work, Jacobus Faure, a South African specialist, “proved” that the Rocky Mountain locust was still alive in its solitary form, except that his data belied his proof. Soon thereafter, an entomologist from Oklahoma, Charles Brett, made a similar claim with even less evidence, but a peripheral experiment of his provided a critical clue that was overlooked, even derided, for decades.
The bizarre anatomical work by the great American entomologist Theodore Huntington Hubble, on the genitalia of male grasshoppers, provided the definitive method for determining whether the Rocky Mountain locust had truly disappeared. The Smithsonian Institution’s Ashley Gurney used Hubble’s discovery to finally declare that the creature had been a true species—and that it was extinct (a finding that was confirmed half a century later in a Canadian laboratory through the wonders of molecular genetics). And so, a case that had been closed for decades based on the contention that the victim was still alive, albeit in another form, was reopened—only to be summarily closed. To explain the locust’s extinction, entomologists alluded to a discordant and sometimes contradictory set of large-scale changes in the West.
As an entomologist, I was initially drawn to the mystery of the Rocky Mountain locust’s disappearance as a scientific problem. Although superficially satisfying, the explanations for the extinction were ecologically implausible. When I again reopened the case, my interests were objective and my approach was purely professional. But such scientific mysteries are charged with controversy, and I found myself oddly allying with the case’s most apparently misguided investigator, Charles Brett. Engaging in fiery debates, spending weeks and months looking for evidence in shadowy museums and on vast grasslands, and digging through frozen mud and crumbling maps turns a scientific riddle into a personal quest. Solving the mystery of the Rocky Mountain locust has taught me a great deal about the life of the locust, the history of the West, the ways of science—and myself. In the end, perhaps I simply rediscovered a century-old insight of America’s greatest entomologist, Charles Riley, who came to understand that “in libraries and museums, the entomologist may find the dry bones of knowledge, but only in Nature’s own museum can he clothe those dry bones with beauty and life.”
1
The Third Horseman of the Apocalypse
FOR MOST OF US, INSECTS ARE MERELY A SOURCE OF annoyance. Our panicked response to the mosquito-borne West Nile virus is the exception that proves the rule. We’ve become so used to insects being a marginal nuisance that when these creatures are transformed into vectors of disease (however mild in most cases), we panic. Compared to the total number of human deaths from West Nile virus in the United States in 2002, ten times more Americans died as a result of talking on their cell phones while driving, and influenza killed more than a hundred times as many people. But in the nineteenth century, insects were more than an inconvenience. During the Civil War, half of the white troops and fourth-fifths of the black soldiers in the Union Army contracted malaria and several thousand died. By the 1870s, the country had suffered the ravages of two of the Four Horsemen of the Apocalypse—war and disease.
Although many of the settlers had evaded the devastation of war, nearly all were agonizingly familiar with disease. Their journeys were shaped by the reality of pathogenic microbes and crippling parasites. Beating the other pioneers to an early start in the spring meant risking exposure to blizzards, but it also meant minimizing exposure to contaminated water that would accumulate as waves of migrants trekked westward later in the year. Encountering the chill of hypothermia was worth avoiding the scourge of cholera. This bean-shaped bacterium with a long whiplike tail was the primary killer on the Oregon Trail. Thousands of graves strung along the route attested to the power of this horrible disease, which killed half of its victims and wiped out entire wagon trains. Infections could take a person from good spirits in the morning to agony by noon and death by evening. Intense stomach pain would be quickly followed by devastating bouts of bacteria-laden diarrhea, draining the wretch of a quart of fluid every hour. Such a loss rapidly dehydrated the exhausted sufferer—and assured the pathogen of finding another victim through the vile trailside conditions. The only hope for a wagon train was to move ahead of the dying pioneers, leaving the blight to fall on the next travelers to come along.
There was another good reason for departing early in the spring, although the settlers were not fully cognizant of this advantage. The sooner a wagon train got under way, the less time the pioneers spent in the filthy conditions at the trail head. Many of the migrants acquired body lice in the crowded riverboats and rundown boarding-houses while heading to, or waiting at, the “jump-off” points for the overland migration. Like six-legged grains of rice, these bloodthirsty insects caused a tormenting itch, but far worse was their ability to transmit disease. An infected person would suddenly come down with a headache, chills, and fever perhaps a week or so into the journey. Soon, a faint, rose-colored rash would spread over the body and the victim would be unable to keep pace with the rest of the party. Lucky patients might be laid on some quilts on the floor of the prairie schooner. The rattling sickbed would aggravate the pain in their muscles and joints, but at least the wagon’s canvas bonnet would keep the sunlight from hurting their eyes. And if they were truly fortunate, in a couple of weeks they’d have recovered enough to walk alongside the wagon. But nearly a third of pioneers who climbed weakly into a prairie schooner with the raging fever of typhus would not step back down from the wagon alive.
The settlers often hosted other, less lethal but perhaps more loathsome stowaways within their bodies. Abdominal pains were common ailments, and the lucky individuals were only suffering from threadlike pinworms. The less fortunate harbored earthworm-sized parasites in their intestines. These roundworms would cycle through a person’s body every few months. The adult worms laid eggs in their host’s small intestine, and the offspring bored through the bowels and traveled through blood and lymph. This ghastly process would culminate with the worms’ penetrating the lungs, working their way up the bronchial tree, and being reswallowed to continue the cycle. The hideous hitchhikers managed to extract their modest meals from their host’s bowels, leaving the human’s vital organs largely unscathed.
For the settlers who avoided or survived the brutality of war and the ravages of disease, the arrival of locusts brought the frontier to the brink of the Third Horseman of the Apocalypse, famine.
Hunger was pervasive in locust-afflicted lands. In addition to devastating crops, gardens, pastures, and orchards, the masses of locusts inevitably contaminated surface waters that the settlers and their livestock required. Farmers in Utah reported skimming six bushels of locusts an hour from streams after swarms had settled on the region. Although there were allusions to the water being “poisoned,” the locusts were not directly tox
ic. However, the putrefying bodies of the insects surely turned ponds, streams, and wells into undrinkable stews.
The strangest but least serious causes of food losses during locust invasions had nothing to do with the insects’ consuming farm products—indeed, quite the opposite. Poultry were an important source of protein for many homesteaders, and to the initial delight of the settlers their birds stuffed themselves on the locusts. Although the insects had no defensive chemicals in their bodies, a diet saturated with locusts rendered the eggs and flesh of chickens inedible. Studies at the time found that the locusts were remarkably rich in a “reddish-brown oil of very pungent and penetrating odor,” and perhaps this accounts for the tainted meat. There were several reports of turkeys, never considered the brightest animals, gorging themselves to death amid the more-than-you-can-eat banquet of locusts. Farmers eventually discovered that feeding the birds some grain before their gluttonous splurge prevented lethal overeating.
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