Locust

by Jeffrey A. Lockwood

  Like Riley, as a teen Packard became a keen collector of natural objects, including shells and insects, and soon became quite accomplished in artistically depicting his finds. He devoured Bowdoin’s books on natural history and entered the college at eighteen. After graduating, he began studies with Louis Agassiz, the renowned Harvard zoologist. Packard’s affiliation with Agassiz surely sowed the seeds for future conflicts with Riley, for Agassiz was one of the most strident and powerful adversaries of Charles Darwin. Darwin argued that new species arose via natural selection, which operated to favor the survival and reproduction of those forms that were most successful in meeting the challenges of an ever-changing set of conditions. Agassiz found little evidence of such gradual change of life forms in the fossil record, although he admitted that entirely new species often appeared in geological time. As such, he resorted to a hybridization of creationism and science:The most advanced Darwinians seem reluctant to acknowledge the intervention of an intellectual power in the diversity which obtains in nature, under the plea that such an admission implies distinct creative acts for every species. What of it, if it were true? Have those who object to repeated acts of creation ever considered that no progress can be made in knowledge without repeated acts of thinking? And what are thoughts but specific acts of the mind? Why should it then be unscientific to infer that the facts of nature are the result of a similar process, since there is no evidence of any other cause? The world has arisen in some way or other. How it originated is the great question, and Darwin’s theory, like all other attempts to explain the origin of life, is thus far merely conjectural. I believe he has not even made the best conjecture possible in the present state of our knowledge.

  Packard had previously been impressed with the writings of Jean-Baptist Lamarck, whose theory of evolution was based on the notion that environmental factors and biological need caused organisms to change. These changes were then passed to the offspring through what became known as “the inheritance of acquired characteristics.” For example, a giraffe’s neck became incrementally longer by its reaching high into the trees for food. The elongated neck achieved through a life of stretching was then passed on to the offspring as their starting point in the next generation. Lamarck’s theory was perceived as being counter to Darwin’s, although Darwin made some use of his adversary’s notions because they provided a means for rapid change—and neither the age of the earth nor the mechanism of genetic inheritance was yet known to the scientific community. Given Agassiz’s opposition to Darwin, based on an odd amalgamation of religion and paleontology, he found Packard to be a welcome ally. Indeed, Packard would later write a biography entitled “Lamarck, the Founder of Evolution.” Riley had derived considerable intellectual status from his association with Darwin, and so evolution became not only a flash point within society but a sore point within the U.S. Entomological Commission.

  Packard’s personality was also rather contrary to Riley’s. The former was variously described as, “fair, modest, retiring, and dignified . . . kind and courteous . . . entirely honorable, and never forgot to give credit for assistance of any kind to younger men, in a day when this was by no means invariably the custom.” In short, he had few qualities in common with Riley. Although he was unassuming, Packard also had “a tremendous spirit when roused to anger.” And who could provoke this quiet man? Authoritarians. Along with the other assistants in Harvard’s museum, Packard revolted against Agassiz’s strict discipline and low pay, a situation that came to open rebellion when a new regulation decreed that assistants could not have private collections—all of their material was to be given to the museum. Although Packard left Cambridge over this conflict, he remained on good terms with Agassiz, a testament to the young man’s conciliatory ways. But Packard surely bristled under the leadership of Riley, who was even more impolitic than Agassiz.

  In 1864, Packard earned his bachelor’s degree from the Lawrence Scientific School at Harvard and his M.D. from the Maine Medical School. He then received a commission as Assistant Surgeon of the First Maine Veteran Volunteers. During his service in the Civil War, Packard saw stiff action in Virginia and won a commendation for bravery. And so not only was he a graduate of the oldest and most elite university in the country, he was something of a war hero. Riley’s degrees were honorary distinctions from an embryonic university in the Midwest, and his war service consisted of standing guard duty.

  After the war, Packard published an impressive series of works on natural history and traveled to Europe to meet a bevy of famous scientists. By October 1876, when the western governors were meeting in Omaha, Packard had already published the standard textbook of entomology and had just completed work with one of Hayden’s surveys. Packard was well on his way to becoming one of the foremost zoologists in the country. And in his role as state entomologist of Massachusetts, he had recently expressed concern that economic entomology in the United States was lagging far behind that in Europe. So, who better to ensure the scientific veracity and intellectual credibility of the country’s first Entomological Commission?

  Packard might have trumped his chief’s academic record, but Riley had an ace in the hole. He had the high ground in terms of authentic connections to rural life: Riley had been a farmer. Having worked the land, Riley had firsthand experience and a devotion to agriculture that Packard could not assert, had he been the sort to make self-serving claims. Although degrees and diplomas were fine, Riley had devoted his career to applied entomology, and he was intimately familiar with the struggles of the farmer. But then there was Cyrus Thomas.

  Thomas had led a Lincolnesque life. His earthiness was rooted in rural Tennessee and village schools, far from Riley’s gentrified London and art academies. Born in Kingsport, nestled between the Appalachian and Great Smoky Mountains, Thomas never went to college but studied math, science, and law on his own. The gifted young man was admitted to the Illinois bar at the age of twenty-six and practiced law in Murphysboro on the banks of the Big Muddy River. Comfortable in his legal practice, Thomas decided to expand his horizons and sought a branch of science in which to carve a niche for himself. Having come from rural obscurity, he aspired to fame—and entomology was his ticket. Thomas, an exemplar of pragmatism, reckoned that the study of insects was eminently affordable and the objects of interest were invariably close at hand.

  Despite the calculated practicality of Thomas’s decision, he was soon motivated by an authentic sense of excitement and accomplishment. He loved contributing articles on economic entomology and published his first paper while still practicing law. Thomas soon found chasing insects far more to his liking than pursuing litigants, and he emerged as a potent and respected force in the field of science. With his penchant for legal debate, Thomas entered the fray in various entomological controversies, including the infamous brouhaha over the armyworm’s biology (recall the nasty argument between Benjamin Walsh and John Klippart in the nation’s agricultural press). However, his real strength was in collaboration rather than argumentation. Thomas is widely acclaimed for having laid the foundation for the Illinois Natural History Survey, serving as its catalyst and first curator. Having flourished for 145 years, this survey constitutes the nation’s largest and most successful such venture. With more than 200 scientists and staff, including 22 economic entomologists, Thomas’s legacy represents one of the finest ecological research units in the modern world.

  Although there is no record of Thomas’s role in the Civil War, this was a period of dramatic personal transformation. With the death of his wife in 1864, Thomas quit the practice of law and became an evangelical Lutheran minister. But his “intense independence of thought” did not predispose him for a long career in religion, so he abandoned this profession for his lifelong calling—science. However, his theological training was not so easily deserted and caused him to struggle with the emerging theory of evolution. In recounting a discussion with a minister-naturalist colleague, he quipped, “You can imagine the scene: these two ex-ministers
of the Gospel, having the advantage over other members of the cloth in being naturalists, puzzling their brains in the effort to harmonize the facts of nature with the teachings of the church.” Later colleagues characterized his position as being theologically nuanced but generally supportive of evolutionary theory. Yet Riley would have none of it. In reviewing the biology of the Rocky Mountain locust, Riley considered the possibility of gradual changes between generations and caustically asserted, “The same possibility has also been suggested by Prof. Thomas—a professed anti-Darwinian—in an elaborate paper published in October, 1875.”

  Whatever his stand on evolution, Thomas was able to recommence his scientific studies and soon returned to prominence. Like Riley, Thomas’s academic credentials were unconventional but served his purpose. He was awarded an honorary Ph.D. by Gettysburg College and was appointed professor of natural sciences at Southern Normal University in Carbondale, Illinois. The following year, Thomas was appointed as the third state entomologist of Illinois (after Benjamin Walsh’s death, William LeBaron had served in this capacity until his own untimely and unusual death due to sunstroke). The state, however, was too beggarly to provide him with anything more than a salary, thereby vindicating his choice of entomology as a science that could be productively pursued on a shoestring. Lacking the capacity for practical fieldwork, he devoted his labors to taxonomy. Thomas’s accomplishments were noteworthy and landed him a position as entomologist on Hayden’s survey in 1873.

  The survey’s goal was to assess the agricultural resources of the western territories, and this objective offered Thomas the opportunity to demonstrate his intellect and integrity. Despite ardent claims by land speculators, Thomas argued that there was simply too little rain to sustain crop production throughout much of the country west of Iowa and Missouri. But unlike Riley, who loved nothing better than publicly refuting an opponent, Thomas was almost apologetic in his assertion that promoters had been painting a deceptively rosy (or verdant) picture of the Great Plains: “I dislike to make such statements, but I deem it my duty to speak plainly on this point.” Such truthfulness put him in good stead with Hayden, who valued scientific objectivity. Consequently, when the opportunity arose to form an Entomological Commission, Thomas was well positioned to take an active role in politicking through the Department of Interior.

  So it was that a European artist-turned-farmer/writer-turned-entomologist teamed up with a Harvard zoologist-turned-physician-turned-entomologist and a country-lawyer-turned-minister-turned-entomologist to form the first U.S. Entomological Commission—one of the most formidable teams of scientists to ever tackle a problem of the natural world. But first, they had to tackle their own problem: how to work together. The solution was as practical as the task before them. They’d simply divide the country into sectors and go their separate ways, coming together only when necessary to exchange information or conduct business. Riley would serve as the chief, which meant that he would be the spokesman and play the central role in drafting and editing the commission’s reports and recommendations. Not only did he covet the mantle of leadership, but his lack of attention to administrative details and his propensity for financial expediency made the roles of secretary and treasurer highly inappropriate. This arrangement seemed to suit Packard and Thomas just fine, as they were happily occupied with their travels and studies. They viewed the venture as a wonderful scientific expedition and a substantive contribution to the nation. Being neither naive nor altruistic, both would parlay the experience into ascending careers in science. However, neither saw the venture with the political acumen of their extraordinarily ambitious leader. Only Riley had the vision to leverage his position into one of truly impressive power and national influence.

  A SCIENTIFIC REVOLUTION

  Riley’s cardinal principles in guiding the work of the commission were succinctly summarized in the opening paragraph of an early report: “Knowledge is power in protecting our crops against the ravages of a tiny insect, as in all other undertakings; and according as accurate knowledge regarding this locust plague is disseminated among our people, will they be able to vanquish the common foe.” Never before had such a systematic and rigorous scientific approach been taken to a complex environmental or agricultural problem. The breadth and depth of the commission’s work is difficult to summarize, involving everything from beautifully rendered drawings of the locust’s internal anatomy to massive tables of climatological data pertaining to the insect’s outbreaks. However, the trio’s greatest impact on science and society clearly lay in the dual capacity to debunk erroneous notions about the locust and to reveal new insights into its biology. Of course science had been making discoveries about the world’s flora and fauna for many years, but the commission’s breakthrough was in converting natural history into practical knowledge—knowledge that could be used to formulate effective strategies for altering ecological processes. In short, the commission’s work demonstrated that the field of ecology—a term coined in 1869 by Ernst Haeckel, a German biologist—could provide a powerful foundation for modern agriculture.

  Riley and his colleagues made a series of fundamental discoveries that set the stage for developing effective control methods. The commission pioneered the practice of “integrated pest management” (IPM), a strategy in which complementary control methods are used synergistically to prevent or suppress pest outbreaks—and a method that was supposedly “discovered” a century later (when, in fact, the unoriginal practice was merely given a clever name and acronym) as entomologists realized that sole reliance on insecticides was doomed. Some of the commission’s revelations are so readily apparent to the modern entomologist as to be overlooked in their importance, until we realize that such facts were far from obvious more than a century ago.

  For example, much of the public believed that the Rocky Mountain locust was the same insect that had plagued farmers of the Old World for millennia, therefore presuming that whatever interventions had worked in other times and places were appropriate for the present onslaught. Moreover, it was commonly held that any grasshopper reaching high densities anywhere in the United States was the nefarious locust. After all, if the beast had crossed an ocean to reach the New World, surely its distribution would not be constrained within North America. Riley and his colleagues were able to show that the Rocky Mountain locust was unique to this continent, being taxonomically distinct from the locusts of Africa, Asia, and Europe. Furthermore, they convinced farmers and others that the grasshopper outbreaks in Georgia, South Carolina, and New England were not the work of the Rocky Mountain locust. These infestations had entirely different origins and required fundamentally different responses. Indeed, what we now accept as the common name of the locust was assiduously defended by the commission against other alternatives. Riley felt strongly that the species’ name should reflect its biogeography and thereby remind the public of the creature’s origin.

  Biogeography arose as a scientific venture with the capacity of nineteenth-century European explorers to travel the globe and catalog the world’s flora and fauna. Driven by curiosity and economics, these expeditions—the most famous being Darwin’s voyage on the British survey ship the Beagle—revealed striking patterns in the distribution of living organisms. The ability of the U.S. Entomological Commission to travel the West by rail and horse provided these entomological explorers with the mobility necessary to map the distribution of the Rocky Mountain locust. And what they found was tremendously important. Riley and his commission were able to document the origin of the locust’s outbreaks within the area that they designated as the Permanent Zone. They also traced its migration circuit (from the mountains into the plains and back again over the course of several generations) and its ecological limits. Contrary to impassioned cries that the locust would overrun the country, the entomologists showed that the swarms invariably petered out near the Mississippi River. As Riley noted:To the unscientific mind there are few things more difficult of apprehension than that species, whether of pl
ants or animals, should be limited in geographical range to areas not separated from the rest of the country by any very marked barriers, or by visible demarcations. Yet such is the fact, known to every naturalist; and the geographical distribution of species form at once one of the most interesting and one of the most important studies in natural history.

  Fundamental discoveries of the locust’s population dynamics also repudiated other prevalent misconceptions about causes of the creature’s outbreaks. Fallacious reasoning had given rise to the prevalent notion that droughts were caused by prairie fires set by settlers to clear the land for planting. In turn, the dry air allowed the Rocky Mountain locust to fly easily through the atmosphere and extend its depredations into the Great Plains. Based on these notions, legislatures considered laws prohibiting farmers from setting fire to the grasslands. Riley argued that the cause-and-effect sequence was entirely mistaken. Rather than fires causing drought, drought created the conditions that fostered both natural and man-made fires. Furthermore, his studies showed that locust flight was not extended by a parched atmosphere but that the hot conditions during a drought created longer periods during the day in which the cold-blooded creatures could sustain activity. The commission maintained that outlawing the burning of prairie grasses would have little effect on suppressing the locust—indeed, quite the opposite. They advocated burning fields where the locusts had laid eggs to deprive the hatchlings of food.

  Even the locusts’ behavior was the subject of misunderstandings, which might well have led to absurd management practices if not refuted. The entomologists found that, contrary to popular opinion, the bands of immature nymphs were not led by “kings or queens,” nor were their movements governed by large “guide locusts.” Had such an insectan command structure existed, then the bands could have been dispersed or sent into chaos by the strategic destruction of their leader—and considerable resources would have been wasted in such a misguided effort. Riley discovered that the nymphal bands were leaderless mobs, orienting to one another and to environmental cues. What farmers presumed to be guide locusts were simply the brightly colored adults of an earlier-hatching species that sometimes exploited the same fields as the locust nymphs.