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.”
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The Third Horseman of the Apocalypse
F
OR 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 toxic. 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.
The clearest and most strident warnings of impending famine were issued by military posts in the locust-afflicted region during the 1870s. The concerns of General Edward Otho Cresap Ord were substantiated by detailed surveys and heartrending accounts by other officers. After one of his staff, Major N.A.M. Dudley, toured portions of Nebraska in October and November of 1874, he wrote to the Secretary of War warning of impending disaster:
The other [locust victim interviewed in one township], J. V. Ferguson, who was sick, has a wife and two children; he had only ten pounds of flour, remnant of a sack received from the aid society, and about two pounds of fresh pork, given him by a neighbor. With quivering lips and moistened eye he said he did not know where he was to obtain a further supply. Both of these families have most excellent claims; one owns a horse and the other a pair of oxen. To sell either is out of the question, as there is little or no money in the country, and then, as they stated, they would be without the means to haul fuel to their homes during the winter, and in the spring they would have no means of cultivating their crops. . . . A young man by the name of Warren, who lives on Muddy Creek [served] through the war in the Union Army. He said his wife had a babe only ten days old; that he had four other children in the house; that they had not had anything to eat for nearly two days until that morning, when he got fifteen pounds of potatoes from the aid society. I gave him a sack of flour and a little pork. I took down the statements of most of the gentlemen; all agree to the main fact that suffering existed now; that it would increase, and unless other and more extended supplies were furnished than those now counted on, people must either leave or suffer the pangs of starvation.
The officer’s firsthand descriptions are compelling, but he also interviewed community leaders for their assessment of the broader situation. These testimonials told a consistent tale:
Mr. Burton is reputed to be a gentleman of unquestionable integrity. He said, “I do not like to believe anybody will starve in the valley, yet I do not know how they are to avoid it, unless they receive a greater assistance than any yet contemplated; some, no doubt, will go out of the country to avoid suffering; some have not the means to get out, and no place to go if they leave.”
Being uncertain that his evocative stories of individual families and the testimonials of local authorities would be sufficiently convincing, Dudley attempted to quantify the dire conditions prevailing in the region. His systematic approach revealed that in the most desperate precincts, four out of every five families were at risk of starvation in the coming winter. In the best of circumstances, one-third of the people required assistance. Although he was a veteran of the atrocious suffering of the Civil War, Dudley was clearly moved by the plight of the settlers. He could not resist concluding his report with a plea for immediate action on the part of the government:
Great suffering exists in all five of these extreme frontier counties to a fearful extent. The settlers are, in most instances, scattered over a large extent of country; a large portion of them living far up the numerous streams flowing into the Republican. If the winter should be as severe as that of seventy and seventy-one, and as deep snows fall, beyond a doubt hundreds will starve unless a supply of provisions sufficient to last them through the winter is thrown into the valley and they are provisioned for an emergency of this character, for it would be out of the question for any aid society, or the Government even, to reach anything like a majority of them in deep snows.
Although recent homesteaders were extremely vulnerable to the depredations of locusts, hunger was not limited to the leading edge of the frontier. Far to the east, rural communities were struggling to feed themselves following the arrival of swarms. From Missouri’s St. Clair County came this distraught call for help:
We have seen within the past week families which had not a meal of victuals in their house; families that had nothing to eat save what
their neighbors gave them, and what game could be caught in traps, since last fall. In one case a family of six died within six days of each other from the want of food to keep body and soul together. But it is but justice to say that the neighbors and citizens were unaware of the facts of the case and were not, therefore, responsible for the terrible death which overtook these poor pilgrims on their journey to the better land. This is, we believe, the first case of the kind which has transpired in this county; but, from present indications, the future four months will make many graves, marked with a simple piece of wood with the inscription “Starved to death,” painted on it.