Locust (34 page)

The next morning, Bill was limping with a twisted ankle that he’d suffered shortly after Larry and I left him with Jim—whose groin pull had stiffened like a frozen cable overnight. We were battered and humbled, but at least the sun was out, so a warm, dry day of rest seemed an ideal remedy. After a morning of fishing for grayling at a nearby lake, we met over lunch to discuss our options. We had another three days before the packers would come for us, and it was evident that if we were going to make another assault on the glacier it would be best to wait until the last day. If injuries had healed sufficiently, then by heading up the east side of the lake we thought it might be possible to make it onto the glacier. We estimated that most of the ice was at a precipitous thirty-degree slant, but the flanks of the glacier looked to be a bit more accessible. In the next two days, Larry and I made a reconnaissance hike to the valley that held Hopper Glacier. Although this body of ice could be seen from the trail, getting there would require a grueling climb, perhaps even nastier than the route into Grasshopper Glacier.

After two days of glorious weather, the dark clouds returned with a vengeance. The afternoon before our planned return to the glacier, a soft rain began to fall. By the time we were huddled under a tarp making dinner, the rain had changed into a heavy snow. As night fell, so did our hopes. It was clear that the window of opportunity had closed. Under these conditions, an attempt to reach the glacier would be foolhardy, and even if we made it, the ice would be blanketed in snow—just as we’d found on our arrival at the first Grasshopper Glacier two years earlier. I sat damp and dejected in my tent. A few grasshopper parts tucked away into a small vial were all we had to show for our expedition. The horses would haul out four hundred pounds of equipment and about four milligrams of specimens. Sometimes, however, adversity is the mother of invention.

After returning to my lab in Laramie, I laid out the five mandibles, like chips of polished ebony. “That’s it?” asked Scott Schell, one of my graduate students at the time. He had a keen sense of the time and expense that had gone into getting these tiny structures.

“Yeah,” I replied, “not much to work with, is it?” I didn’t want to figure out the cost per ounce of the material from this expedition.

“Well, I don’t know,” he answered, “Wasn’t there a paper back in the 1940s where some guy associated mandibles with feeding preferences in grasshoppers?”

“That’s right,” I replied, the wheels starting to spin. But Scott was ahead of me.

“If mandibles differ enough to distinguish what types of food a grasshopper eats, then maybe they could also tell us what species they came from,” he offered.

Zoologists often rely on teeth to differentiate species of mammals, and dental records are a standard method for identifying human remains. Nobody had ever tried to use insect mandibles in this manner, probably because it would be crazy to extract these structures for taxonomic purposes when the insects had such wonderfully varied and readily accessible legs, wings, antennae, and other features. The grasshopper’s mandible is very much like a tiny molar, used for grinding its food. We had also found a lacinia, a hardened, scythe-like mouthpart used like our incisors to cut pieces of leaves from a plant. However, we’d found only one of these, and the lacinia is not as elaborately sculpted as the mandible. Scott made a series of fine measurements of the mandibles from a range of grasshopper species, including four specimens of
spretus
that the curator at the University of Nebraska was kind enough to allow us to extract from his precious charges. With the statistical assistance of another of my graduate students, Chuck Bomar, it was soon evident that forensic dentistry was a bizarre but effective approach to sorting out grasshopper species. The mandibles from Grasshopper Glacier matched those of
spretus
, whereas all of the other species were clearly separate and distinct. Excited by both the discovery of
spretus
(as far as we could determine) and the development of a unique method for identifying grasshopper remains, we submitted a manuscript for publication.

Although the paper was accepted, my colleagues were clearly unimpressed. With this third paper on glacial remains claiming that the ghost of
spretus
was seen in decomposed remains dug from icy graves, the reviewers made acerbic reference to my lab having yet again “found” the long-lost locust. The sense was that our objectivity was compromised by our devotion to the search—that we were
looking so hard that we were destined to see the Rocky Mountain locust whether it was really there or not. The reviewers begrudgingly accepted the use of mandibles as a means of identifying the grasshopper remains, insisting that we restrict our conclusions to the narrowest possible interpretation—that we had found mandibles more consistent with those of
spretus
than with those of the other species examined in our analysis.

We’d gained a small victory by having our latest work published, but it was evident that the scientific community was not going to tolerate any more discoveries of rotting and fragmented insects from glaciers. As one reviewer tersely noted, “This paper only warrants a very short note. . . . The authors already have five articles on these grasshoppers.” If we wanted to claim that glaciers of the West harbored a hidden biological treasure, then a few flecks of gold were not going to cut it. We had better find the mother lode—intact and unambiguous specimens of the Rocky Mountain locust—or drop this crazy treasure hunt.

W
HILE WE WERE SCOURING THE GLACIERS FOR biological treasure, other scientists were documenting their disappearance. The largest concentration of glaciers in the American Rocky Mountains is found in the Wind River Range of western Wyoming, and seven of the ten largest glaciers in the Rockies are nestled among these rugged peaks. These storehouses of frozen water are the aquatic savings accounts for thirsty agricultural enterprises downstream. Although the precise contribution of these ice fields to the region’s water supply has not been fully determined, we know that runoff from just two of the sixty-three glaciers accounts for nearly a tenth of the flow into the Wind and Green rivers. These watercourses are the lifeblood of hundreds of farmers with irrigated fields of sugar
beets and alfalfa. In recent years the annual snowfall in the mountains has been inadequate to fill the rivers, so glacial meltwater has become increasingly important, especially in late summer and early fall, when the previous winter’s snowpack has disappeared.

Consuming these ancient stores of water is the equivalent of a business constantly drawing on its capital. There will come a time when the water bank—the high mountain glaciers—runs dry, and irrigated agriculture will evaporate. These glaciers are receding at a rate of 10 to 40 percent each year, and no fund can long withstand such a rate of depletion. Dinwoody Glacier is the second largest glacier in the Wind River Mountains, and the account of its recession is profoundly sobering. The amount of water remaining in this glacier is equal to that which was lost between 1958 and 1983. If this rate of retreat continues, the glacier will disappear in about twenty-five years.

Such worrisome figures have generated intensive studies of the glaciers, as scientists attempt to forecast the loss of these vital resources. A geologist and a hydrologist from the Water Quality Laboratory at Western Wyoming Community College in Rock Springs have spent years monitoring Knife Point Glacier, a sweeping expanse of ice that is part of a string of ice fields stretching for ten miles along the continental divide. This complex comprises the largest store of frozen water in the United States, including the two largest glaciers in the American Rockies. Craig Thompson, the laboratory’s director, is a vibrant fellow with an irrepressible sense of curiosity. He is a consummate organizer and made the logistical nightmare of the twenty-five-mile treks into the glacier possible. His partner, Charlie Love, is the son of Wyoming’s most famous geologist, David Love, immortalized in John McPhee’s
Rising from the Plains
. Charlie is a weathered and irascible fellow who looks as if he’s probably been “nearly sixty” for a good many years. He is an accomplished geologist, but he is best known for his anthropological work on Easter Island. In 1987, when we were on our first trip to Grasshopper Glacier outside Cooke City, Craig and Charlie had chipped loose a couple of softball-sized hunks of ice from Knife Point Glacier. They were intrigued by the composition—the samples were encrusted with insect parts.

Wyoming has been described as a “small town with very long streets,” a reference to the fact that with only 490,000 people there is a statewide sense of being a community—and news manages to find its way throughout the populace. So it was not surprising when I received a call from Craig shortly after our return from the glacier in 1989. He said that he’d read my papers about the search for the Rocky Mountain locust and that Charlie could give me their frozen blocks of insect remains on his way through Laramie in a couple of weeks. I knew from the moment Charlie lifted the first frozen block from the cooler that this had the potential to be the mother lode we’d been seeking. The ice looked like something that had been chipped from a filthy roadside days after a snowstorm. But rather than pebbles, twigs, and trash, the ice was blackened with grasshopper—or locust—parts. Legs and wings were packed into the most wonderful crusty mass of frozen detritus that I’d ever seen. I thanked him profusely (never had such gratitude been offered for such an ugly gift) and promised to call him with the results of our extraction.

After thawing, the smaller block of ice yielded just two ounces of dried matter. But from this scant material we managed to harvest more than a thousand grasshopper mandibles. This was easily the richest deposit that we’d encountered since beginning our research. However, within the larger chunk we found a biological gem—the intact bodies of two grasshoppers or locusts. Although the bodies were horribly crushed and twisted, they were undeniably in the genus
Melanoplus
. Upon ever so gently teasing away the accretions of grime and silt adhering to the abdomens, we found that both were females. We had found what was likely to be the treasure chest, but the key was missing! The various measurements were all consistent with these being Rocky Mountain locusts, but without the male genitalia we could not be absolutely certain. There was only one course of action. We began to make plans to join Craig and Charlie the next summer on their trek to Knife Point Glacier.

In the intervening months, we obtained radiocarbon dates for the specimens. The deeper deposit yielded an age of 400 to 500 years, and the shallower collection site provided material that was 150 to 250 years old. We now knew that the mutilated females had become embedded
in the ice when the Rocky Mountain locust was alive, so the motivation to reach the glacier became all-consuming and the winter dragged on interminably. To make matters worse, plenty of snow was falling. The possibility that the summer melt would not uncover the ice at 12,500 feet was a miserable prospect.

Spring comes late in Laramie, snow flurries being a tradition during the university’s commencement exercises in mid-May. Given the cost and effort needed to trek from the outfitter’s lodge to the glacier, Craig and Charlie had learned that investing in a reconnaissance flight by small plane was a wise strategy. But there was no point in even looking for a window of opportunity until August. So, through the summer, we conducted our research on rangeland grasshopper outbreaks in the balmy conditions of the Platte River valley, just a couple hours east—and 3,000 feet lower than—Laramie. Roasting in the 100-degree heat near Wheatland, Wyoming, in July, we could look forward to the possibility of frosty nights that loomed just one month later and nearly two miles higher. In early August we got the call from Charlie: “Our flyover yesterday came off without a hitch. Patches of ice are showing through, so we should plan to be on the glacier within a couple of weeks. You guys ready to go?” We’d never been more ready for an expedition.

Gary and Sue Weiss were tremendously hospitable outfitters, feeding us huge slabs of prime rib the night we arrived at the lodge and regaling us with stories of harrowing trips and wild adventures. In the morning, they supervised the packing and saddling of the horses. Our wrangler, a rather sullen but seemingly competent fellow, mounted his horse and led us from the lodge before the sun had peeked over the ridge. The day was clear and we made good time for the first twenty miles. Then the trail deteriorated as we climbed through alpine meadows. The wet rocks and muddy quagmires fed by the last of the melting snowbanks made for treacherous riding conditions. After nearly seven hours on a horse, hiking the last five miles was a relief and gave my legs a chance to stretch in more accustomed ways.

We camped on lush, spongy tundra about a thousand feet below Indian Pass—the gap in the continental divide that would take us to the top of Knife Point Glacier. On the rocky slopes near camp we marveled
at the tiny haystacks drying in the sun. Hearing panicky peeps and catching fleeting glimpse of gray, we knew that these were the work of pikas. Resembling giant hamsters, but most closely related to hares, these creatures are taxonomic oddities, having been placed in a family that has a single genus. Above our camp, Harrower Glacier clung to the side of the valley and looked reasonably accessible, but there had never been reports of grasshoppers embedded in this ice. Various geological reports from the 1930s made mention of five glaciers in the Wind Rivers as having grasshopper deposits. However, surveys in the 1950s did not report the presence of grasshoppers within these bodies of ice, so their contents had presumably been lost to recession and melting. It seemed that Knife Point Glacier was to be our last great cause for hope.