Locust

by Jeffrey A. Lockwood

  A proper—and fundable—grant proposal provides a compelling scientific rationale for the planned research. My proposal to the National Geographic Society included what seemed to be some rather convincing arguments for funding an expedition to what early geologists had come to call Grasshopper Glacier, a magnificent and mysterious body of ice just north of Yellowstone National Park that had attracted western travelers for decades. The most obvious justification for my project was that no entomologist had been to the site in forty years. It also seemed that the condition of a natural phenomenon and national treasure of this sort ought to be monitored. After all, recession had been ongoing since at least 1931, when observers reported a gagging stench emanating from the foot of the glacier, where a four-foot pile of rotting locusts had melted out of the ice. With similar reports in 1952—the last time a scientific expedition had been to the glacier—one had to imagine that this remarkable resource could be in serious trouble and that the chances of collecting the uniquely preserved insects were dwindling.

  The frozen creatures were probably ill-fated swarms of the Rocky Mountain locust, but remarkably—almost unbelievably—none of the specimens collected between 1914 and 1952 had made it back to a museum. The only entomologist to examine the icebound insects had been Ashley Gurney, but he had made his observations before he was aware of the differences between the genitalia of sanguinipes and spretus. So, his identifications indicated that these were the migratory phase of sanguinipes, which may well have been spretus. If it was the Rocky Mountain locust embedded within the ice, it could represent a bonanza of biological material and sufficient evidence to reopen the case of the creature’s disappearance. Furthermore, there were other Rocky Mountain glaciers purportedly containing frozen grasshoppers, although none had ever been studied by an entomologist. There were specimens of spretus preserved in various museums throughout North America, but all of these had been collected in the last few years of the locust’s existence, so they did not represent the species in its vibrant, healthy condition. Perhaps more important, not many specimens existed. A species that once blackened the skies was now a rare scientific commodity.

  There are dozens of insect collections in the United States, housed in universities and natural history museums. The largest collection is Riley’s legacy: The National Museum of Natural History contains 30 million specimens, a couple million more than London’s Museum of Natural History. Harvard’s Museum of Comparative Zoology is the largest of the university collections, with 7 million insects tucked away. At the University of Wyoming, we have a modest collection of 250,000 specimens housed in tall, steel cabinets. Looking among our drawers of neatly pinned and labeled insects, you’re likely to find that the largest numbers of specimens represent the most common species.

  The closest specimen of the Rocky Mountain locust is seventy-five miles to our south, in the Colorado State University insect collection. Deep in the bowels of this collection, five dried locusts are impaled on pins. Across the continent there are another 482 specimens scattered among half a dozen collections, the majority of these being at the National Museum. For an insect that once numbered in the trillions, this is a infinitesimal record. And to make matters worse, many of these specimens were identified before the definitive anatomical features were known, so a portion of these collections actually could be the migratory form of sanguinipes.

  As such, we had a rather limited pool of specimens to expend on various tests. Any specimen lost to analysis was an irreplaceable relic of American history and ecology. But there were now powerful—and destructive—analytical methods with the potential to shed light on the nature of the Rocky Mountain locust and the events leading up to its extinction. For example, we had methods of characterizing subtle differences in the proteins of organisms. By passing an electrical charge through a gelatinous film on which proteins of an organism had been placed, it was possible to separate these “building blocks of life” based on subtle differences in their electrochemical charges. Because proteins are made of amino acids, which are the direct products of genes, they can serve as sensitive indicators of genetic differences in populations and species. The problem was that the museum material had been preserved in the standard manner: They were dried specimens mounted on pins. Proteins are like chemical origami, elegantly folded and layered molecules. When these complex chemicals dry, the bonds holding the folds in place are broken and the integrity of the molecule is lost. This process, called denaturation, occurs in the cooking of an egg. The proteins are heated, which causes the original bonds to break and new ones to form, thereby transforming a gooey fluid into a rubbery lump. And it is impossible to reverse the process: Scrambled eggs cannot be turned back into their slimy progenitors. However, tissues frozen for centuries in ice just might be well enough preserved that we could analyze the proteins. And if so, then molecular analysis could be taken a step deeper into the very foundation of life.

  I maintained in my proposal that the rapidly developing field of molecular genetics could well provide even more telling clues. If the ice had preserved the insects’ DNA, the chemical blueprint of life, then important questions could be directly answered. We could determine whether the species had been in a long-term decline, with extinction being the culmination of a process that had begun long before human disturbance. Molecular analyses could reveal whether the locust had suffered from inbreeding, causing a genetic “bottleneck.” If we could examine frozen specimens of various ages—and photographs of the glacier clearly showed that there had been layers of locusts at various depths within the ice—it would be possible to detect a constriction in genetic variation. This evidence would strongly indicate that spretus had been reduced to abnormally small and isolated populations before dying out. Furthermore, these analyses of the genetic material, rather than bodily structures (including penile oddities), could directly address the fundamental basis for declaring that a life form constituted a true species—the century-old question of spretus’s taxonomic status could be definitively answered. And in the 1980s, such investigations required types of evidence that couldn’t be found in museums.

  So, to make progress on these fronts, we had to have biological material with three qualities. First, we needed numerous specimens from which to derive representative values. Next, the specimens had to be in a well-preserved state for chemical analyses. Finally, and most important, we needed material that represented the natural state of the locust. To understand what may have happened in the final years of spretus’s existence required us to compare its normal, healthy condition to the biology of the creature in its last dying days. Ideally, we could view both time frames by using well-preserved specimens extracted from the ice, but even if only centuries-old material were frozen in the glaciers, the museum specimens would provide at least some context for assessing the species’ condition at the end of its life.

  In addition to providing tissues with these qualities, the glaciers potentially offered a direct window into the locust’s history. If the layers of locusts reported by earlier investigators represented separate depositions over time, then radiocarbon dating could be used to determine when the swarms had lived. In this way, we could know whether outbreaks of the Rocky Mountain locust had been a natural feature of the North American landscape for centuries. Even with Native American accounts, our perspective only extended to the early 1800s. We also hoped to discover whether outbreaks became more frequent with European settlement. Although the theory had been largely dismissed by force of rhetoric, there might have been something to Cantrall and Young’s contention that the irruptions were aggravated, maybe even caused, by human disturbances. Clever arguments and rebuttals are fine, but hard data were needed to refute various theories—and perhaps to develop a viable alternative case.

  The grant review panel concurred that Grasshopper Glacier was a fast-disappearing resource. So fast, in fact, that the panel judged my proposal to be a long shot (Gurney’s reports were, after all, forty years old). Disappointed, but
undeterred, I scraped together funding from a faculty development grant and the Office of Research at the University of Wyoming. They were no more convinced of my finding frozen treasure, but through later conversations I learned that the decision makers had been drawn into a vicarious sense of intrigue and adventure concerning the mystery of the Rocky Mountain locust and the secrets of Grasshopper Glacier. Such a subjective basis for allocating research funds might seem unscientific and oddly emotional. But then, science is, at its core, a profoundly personal enterprise, irrationally motivated and driven by passion.

  Perhaps the most wonderfully wicked irony in science is the notion that the clearest vision into the world is provided by a “double-blind” experiment. In this method, neither the individual measuring the effects of a treatment nor the subject of the experiment is informed of which, if any, treatment has been administered. I was well aware of the ideals of experimental design, as this approach to science was the primary focus of my research program. Although I’d become fascinated with unraveling the story of the Rocky Mountain locust, I had been hired by the University of Wyoming’s College of Agriculture to pursue far more practical matters, such as developing new treatments for rangeland grasshopper outbreaks. In this development research, we sometimes approximate the double-blind design by default. We don’t intentionally keep secret what insecticide was applied to which plot. Rather, as we position thirty or so plots, each the size of forty football fields, on a grassland with few landmarks, it is easy to lose track of what went where. We use plot maps and coded stakes, but it would take a cryptographer or someone with a phenomenal memory to match these with our inevitably arcane coding system. The plot numbers always make sense at the beginning of the summer, but their logic tends to fade with the patina of the prairie as the season unfolds. And as for the subjects of our experiments, the grasshoppers are not informed of which treatment they have received. I sometimes suspect, however, that the condition of their comrades and the declining frequency with which they are encountered leave the insects with a decent picture that something is amiss.

  The double-blind approach to evaluating the effect of a drug or an insecticide is intended to remove the biases from the outcome of the experiment. As a student, I was taught that the power of science lies in its commitment to the ideal of objectivity. The goal was to design, conduct, analyze, and interpret experiments with absolutely dispassionate, uncontaminated reason. In light of the standard “experiments” conducted in the requisite college biology, chemistry, and physics laboratories, this approach was philosophically correct—but demonstrably bad—advice. The student who managed to create matter (a common outcome of syntheses in organic chemistry—most probably the fruit of mismeasured reactants, incidental side products, and worn-out scales) was not rewarded for objective reporting. No praise was offered to the budding geneticist who refuted Mendelian inheritance (a frequent result with fruit flies—most likely the consequence of the winged ones escaping and the wingless ones becoming mired in their gooey food, thereby skewing the proportions of these forms). However, we understood that in the course of “real” science, one had to adhere to the ideal of objectivity with uncompromising devotion.

  The problem with this pedagogical approach was that once I became a professional scientist, nobody was handing me a lab manual full of preconceived experiments. I was hired as an insect ecologist at the University of Wyoming to explore the world of grasshoppers, with a particular eye to managing populations of these creatures when they became unruly. In graduate school at Louisiana State University, my research had been quasi-independent, guided by a gentle mentor and a thoughtful committee. As a new faculty member, I relished the lack of oversight—but freedom is scary stuff. I discovered that the most important and difficult phase of science is asking a good question. Our ignorance of the natural world is such a boundless resource that one must attempt to navigate through a mindscape of tangled paths, blind alleys, twisted streets, and unsigned roads. I had learned the principles of objectively designing experiments, impartially collecting data, rigorously analyzing the results, and neutrally interpreting their meaning. I knew how to answer questions via science, but standing in the midst of a few million grasshoppers milling about on the mixed-grass prairie or a few thousand scientific journals crammed onto the shelves of the university library, I realized that generating results was the easy part of science. The hard part was figuring out what to ask.

  In this defining phase of inquiry, the ideal of objectivity not only fails to provide guidance; it becomes an absurd—if not utterly impossible—standard. I’ve sometimes wondered what it would be like for a scientist to select questions in a purely dispassionate, utterly disconnected manner. Many scientists approximate this condition in pursuing topics that are deemed important by the collective consciousness of their peers in a socially sanctioned, positive-feedback system that provides comfort and security. But this effort to become the lead sheep in the flock, a biologically problematical but conceptually apt metaphor, lacks an objective rationale. Some scientists use the standard of “publishability” and choose the questions that are most likely to yield manuscripts, and still others select the measure of “fundability” and focus on those matters most likely to yield grants. But selecting the putatively objective criterion—peer approval, publication, or funding—is an act loaded with subjectivity. Perhaps the only possible tactic would be to construct a database of all possible scientific questions and then to randomly select one for examination. Such silliness simply reflects the absurdity of the claim that science is a purely objective venture.

  I could not possibly have devoted seventeen years of my life to the study of grasshopper biology and ecology without a passion for these creatures and the lessons they offer. Even taking out time for teaching, meetings, and other duties of academia, I’ve spent a bit more than 2,000 working days—nine years of full-time labor—trying to understand grasshoppers. No sane person would devote such labor, let alone so much of one’s life, to the pursuit of questions that did not touch the heart and soul while stimulating the mind. To have invested that much of life is either a tragic waste of human potential or an expression of faith that there are mysteries and lessons worthy of this expenditure. If each passing day represents an irretrievable gift, then to squander this blessing on the heartless, soulless interrogation of nature would be to offer oneself as a martyr to the cult of objectivity.

  Although my expedition to Grasshopper Glacier was founded on rational thinking and reasoned argument, my desire to explore the frozen remains of the Rocky Mountain locust was personal and subjective. I wanted to stand in the presence of such a strange and wonderful natural phenomenon. There is a grandeur of scale that draws humans into the natural world. For me, outbreaks of grasshoppers and swarms of locusts are a portal into a joyful terror that has long been an inexplicable part of my being. Like being drawn to the edge of a towering cliff or into the deep water beyond the crashing surf, I find myself pulled toward these irruptions of life.

  In the summer before my first trip to Grasshopper Glacier, I remember standing at the edge of the dirt road as the dust from my truck hung over the road for a quarter mile along Whalen Canyon. There, I came to understand how a hundred grasshoppers per square yard transforms the world. They blanketed the skeletons of the sagebrush, gripped the shreds of yucca, and lined the shady sides of the fence posts to avoid the searing heat. In the draws, where the only hint of green vegetation remained, the grasshoppers formed a virtual carpet. They ricocheted off my face and chest, clung to my legs, and boiled in every direction. At this density, the grasshoppers melded into a single, seething ecological tissue into which I was absorbed. One never fully returns from these dream-places where mental, spiritual, and physical experience are inseparable, where we glimpse the vastness of the heavens and the depths of the earth.

  Whether for better or worse, whether driven by objective knowledge or subjective experience, whether seeking the tangible or the inconceivable, I was compell
ed to see for myself the frozen forms of the creatures that had eclipsed the sun. I was drawn to witness the immensity of life captured in the ice long ago. To touch the jumbled masses of locusts, to lift a corpse from its glacial grave, would be to make these fantastic life forms—the individuals, but even more powerfully the superorganisms that emerged as swarms—real in a way that historical accounts and woodcuts never could. Maybe such intimate contact with the creature in its final resting place would trigger a connection, an intuition, a missing link in the chain of events that had ended with the dawn of the twentieth century. Or perhaps it would simply feed my irrational fascination with immensity, my craving for the infinite.

  ROTTEN RESULTS

  The most famous Grasshopper Glacier lies at 11,800 feet in the Beartooth Mountains, just ten miles northeast of Yellowstone National Park. At least three other bodies of ice in the Rockies bear the name, but this is the only one that has achieved notoriety. Although the glacier was omitted from U.S. Forest Service maps before the 1940s, it was known to the miners of the region, who came across the site while seeking gold, silver, and copper. When Riley and his commission were looking for locusts, grizzled prospectors were surveying the West for riches.