Bugs on Ice
Sean Schoville slips an elastic loop around his waist, securing a square piece of foam to his backside. “It’s a trick I learned from an entomologist in Siberia,” he says casually. “It helps you stay warm when you’re sitting on cold rocks all the time.” It may be June, but it’s frosty here at Summit Lake, the highest pass along the Alaska Highway in far northern British Columbia. Standing before us, the 1,905-meter (6,250-foot) Mount St. Paul looks like a scoop of stracciatella gelato, with dark slivers of limestone slicing through the pillowy white snow.
We’re here to hunt for an elusive and unassuming group of insects utterly unperturbed the cold weather. In fact, they love it. Less than an inch long, these creatures—ice crawlers—look a little like an earwig that hasn’t been getting enough sun. They are wingless, have six legs, and a pale, segmented body that ends with two tail-like appendages known as cerci. When the Canadian entomologist Edmund Walker discovered them in Banff, Alberta, in 1913, he was so dumbfounded by their appearance that he gave the group the scientific name Grylloblatta, which roughly translates to “cricket-roach.” Entomologists aren’t known for their media savvy, but that name certainly landed with a thud. “It’s not particularly flattering,” Schoville sighs. “It doesn’t sound great, and it doesn’t help you understand the group.”
But ice crawlers, as their common name suggests, have a thermal superpower, which allows them to flourish at the edges of glaciers. After the sun sets, they emerge from their hideouts deep within rock crevices to scavenge decaying plant matter along with comatose moths, flies, and other insects that have blown onto the snow. The genus Grylloblatta includes almost 40 described species in the western U.S., Canada, Russia, and the Far East. Highly adapted to their frigid environments, ice crawlers remain active at temperatures in the 20s—the same temperatures that cause other insects, including their prey, to shut down or freeze solid. Hold an ice crawler in the sweaty palm of your hand for too long, however, and they’ll go belly-up. One species has been found at 9,000 feet on Washington’s Mount Ranier. Others spend their lives at lower elevations, albeit in the cool crevices of talus piles or inside ice-filled caves.
As a relic from a frozen Earth, ice crawlers’ dependence on cold environments has made them a bellwether for climate change. “If warming is severe enough, it could drive them to extinction,” says Schoville. And of course warming is already taking place, even in northern British Columbia. Since 1900, the average temperature in the region has increased by more than 3 degrees Fahrenheit. By 2050, it is predicted to rise an additional 3 to 6 degrees. The temperature rise alone is probably not enough to kill off ice crawlers, but climate change will reduce the snowpack that insulates their subterranean habitats when it’s hot out, and that allows them to forage when the temperature is right. Although British Columbia has on average been getting wetter in recent decades, its snow cover has decreased by 10 percent since the 1960s, and snowmelt now begins almost a month earlier than it used to.
Because ice crawlers tend to be found only in tiny pockets where climate and habitat are just right, Schoville and other scientists consider almost every species at risk of extinction. Unfortunately, they are collected so rarely that no one has really been keeping track of how they’ve been faring as the climate shifts. Schoville, a professor at the University of Wisconsin at Madison, has made it his mission to return to the original localities where ice crawler species were first discovered in order to understand both their evolutionary history and, more pressingly, their response to climate change.
During the last ice age, ice crawlers seemed to be restricted to low elevations. Then, as the climate warmed, some migrated up slopes, following the retreating edges of glaciers. Those remaining in the lowlands, meanwhile, sought out long-since-cooled lava tubes, such as those found at Lava Beds National Monument, where the porous, insulating rock serves as a sort of natural ice chest, preventing warm air from penetrating and preserving underground ice formations year-round.
The six species of ice crawlers that researchers had previously identified in California were defined largely by external differences in the male genitalia, which tend to evolve rapidly. Their genetics, however, told a different story. Schoville discovered that there might be as many as a dozen species. But he couldn’t just start sticking names on them. He needed to sort out which insects were truly new and which ones had already been described. “I realized there was a problem there,” he says. “I hadn’t seen the type specimens.”
For all the adventures of specimen collectors like Schoville, the naming and organizing of life’s diversity is also about hunting down old specimens in museum basements, and leafing through yellowed monographs. Not just a quest for the new, taxonomy has always been a conversation with the past.
Swedish botanist Carl Linnaeus laid the foundations of taxonomy in the 18th century by creating the two-part Latin species names we still use today. Scientists who followed Linnaeus formalized the practice of designating a single type specimen to represent each newly described species. Just as a single cylinder of metal housed inside three bell jars in Paris is the international prototype of the kilogram, a small flowering plant that Linnaeus collected, pressed to sheet a paper, and filed away in a museum, serves as the official representative of Cistus oelandicus.
Examining the type specimens and returning to the localities where types were collected is central to settling disputes and determining whether a group of related organisms should be lumped together or split apart. Such taxonomic research helps scientists understand whether a species is comprised of just a small, isolated population under threat of extinction, or if it is made up of multiple populations that are widely distributed. For example, population geneticist Michael Russello of the University of British Columbia in Okanagan determined that Santa Cruz island in the Galápagos is home to not one, but two species of giant tortoises. The realization has transformed the way in which the islands’ breeding programs are managed.
Understanding the relationships among ice crawlers could provide a window into how much alpine ecosystems are changing with the climate, and also help protect them from more immediate development threats. One endangered population of ice crawlers in eastern Washington, for example, may be a new species, which would be harmed by the proposed expansion of the Mt. Spokane Ski and Snowboard Park. A population that once lived around the Mount Hood ski areas in Oregon appears to have already gone extinct, possibly due to the nightly grading of ski slopes.
Although Schoville made good progress early on in his quest to delineate new ice crawler species, he eventually hit a stumbling block. Out of the six described species in California, three of the type specimens couldn’t be found. Among collections of North America species, nearly a dozen type specimens were untraceable. According to the records Schoville was finding, the prime suspect in the case of the missing ice crawlers was a name he knew well: Bill Kamp—“the greatest Grylloblattid collector that ever was,” according to Schoville.
According to the records Schoville was finding, the prime suspect in the case of the missing ice crawlers was a name he knew well: Bill Kamp—“the greatest Grylloblattid collector that ever was.”
Kamp excelled at rearing ice crawlers in captivity, and learned, for example, that they can survive a long time, possibly ten years—an extraordinary lifespan for an insect. His studies also revealed that ice crawlers have extremely narrow temperature tolerances. Most ice crawlers won’t leave their hideouts if the air temperature rises above 40 degrees Fahrenheit, and if their body temperature exceeds 80 degrees, they die. They’re also unable to survive freezing.
Insects typically adopt one of two strategies to deal with cold temperatures: freeze-avoidance or freeze-tolerance. Freeze-tolerant insects, including caterpillars, cockroaches, and midges, stop eating to prepare for winter, so that food particles can’t seed ice crystal formation, which would kill them. Some also have so-called cryoprotectants in their tissues, which further prevents ice crystals from forming and shattering their cells. These adaptations allow the insects to survive being frozen solid and thawing out again.
Ice crawlers, in contrast, have evolved a clever freeze-avoidance strategy that allows them to stay active in—and in fact take advantage of—cold temperatures. Kamp discovered that ice crawlers freeze at lower temperatures than most other insects. That’s because their bodies contain fats that remain liquid at cold temperatures—think olive oil, rather than butter—and this likely functions as an internal antifreeze. Like any antifreeze, the ice crawlers’ system has limits, which helps to explain how the insects can stay active in the cold, but also why they’re not found in Alaska, the Yukon, or other places with permafrost soils.
Having settled back in Vancouver, Kamp met a scientist and professor named Mary Taylor, who studied Australian mammals. The two thrived off each other. “He loved the out of doors and so did I,” recalls Taylor, who is now 85. In July 1971, the pair discovered a new species on the ice fields of Oregon’s McKenzie Pass. Over the next decade, Kamp published descriptions of five new species or subspecies. His dissertation suggests that he intended to describe five more, but then his life began to take a downward spiral.
He couldn’t find steady employment and was diagnosed with cancer, an illness that required operations to remove his tongue and part of his jaw. He began drinking—“Either trying to end it all or forget or maybe both,” he later wrote David Kavanaugh, a curator of entomology at the California Academy of Sciences. “I sure poured a lot of money into the bottle with nothing to show for it.”
Kavanaugh was one of many curators who had loaned Kamp type specimens over the years and, by 1985, was delicately asking for their return. “About your Grylloblatta, have I worked on them recently, Hell no,” Kamp replied. “Will I ever work on them I wish I knew for certain.” In 1990, Kamp died at the age of 60 without publishing another species description. “So much had taken a toll on his body,” says Taylor.
Kamp sent Kavanaugh the specimens he requested, but the whereabouts of many other specimens he had borrowed or collected himself are unknown. Kamp told one researcher who sought them that they were in a safety deposit box. Taylor remembers Kamp giving his personal specimens to museums in Australia, Europe, and Michigan, but admits his records from that period were “sketchy.” So far, scientists who have gone looking for them have come back empty-handed. Replacing these valuable specimens might be the only option.
This far north in early June, dusk doesn’t settle until midnight. Schoville and I set out on the trail in full light, the two-day-old snow crunching under our feet. Our route follows the edge of a ravine for about a mile and then the trail veers to the right, up a ridge. Our plan is to head across the boulder-strewn stream below and then scramble up into the cirque, a theater-shaped valley beneath the cliff bands of the mountain. Before ascending, we notice silhouetted figures clambering across what looks like impassible terrain between cliff faces—a herd of Dall sheep moving west.
After rock-hopping across a roiling stream of snowmelt, we climb into the valley and periodically drop into hip-deep drifts of snow. A few days earlier, we were told, the temperature was in the 90s and the mountain was bare. Now, these deep patches of snow are interspersed with sharp-edged, cinder-block-sized rocks. With every step, I never know if I’m going to find solid footing, bash my shin on a rock, or sink into the fluff. I have snow pants on but no gaiters, and after just a few minutes, my boots are wet and my toes are getting cold. It’s still early—about 9 p.m.—when we find a flat rock to drop our packs on.
The ice crawlers wouldn’t be coming to the surface until dark, but Schoville is anxious to find them. The memory of his failed trip still stings and now he has a reporter out from New York watching his every move. He hops down and heaves a rock out of a moss-filled nook. After all the hard work to get to this point, the first specimen comes surprisingly easily, and Schoville’s joy is unmistakable. “I found one!” he says. “A female.”
Schoville’s prize is brownish with long antennae, eyes the size of a pepper grain, and a plump abdomen. He sets her on the snow to keep her cool and we watch her zip around as nimbly as a centipede in the summertime. Kamp’s G. c. athapaska still existed after all. It’s a promising sign, an indication that even after searing, snowless days, ice crawlers can persist. Schoville drops the insect into a small plastic cup, pops the lid on, and sticks it into his pack.
Although a few specimens of G. c. athapaska do exist at the Canadian National Collection in Ottawa, Schoville explains to me he needs the fresh ones he collects here for their DNA, and he is bringing a few live ones back to Wisconsin to understand how they cope with extreme high and low temperatures.
He suspects that G. c. athapaska may be genetically distinct enough from other ice crawler populations that it ranks as its own species. In fact, it may represent one of the most ancient branches of ice crawlers in North America, and could help explain how and when the insects originally spread here from Asia. Did they cross via the Bering land bridge in the last 5 million years? Or do they date to an earlier time when the two continents were connected? These specimens, he hopes, will help him answer that question, and to make predictions about how future climate change could impact the group.
In the ten years since Schoville began this research, he has collected ice crawlers from all over the world. Eyeless ones from a cave in Korea. Subterranean ones from sea level around Nagasaki, Japan. High-altitude ones from the Altai Mountains in Siberia. He’s published descriptions of three new species from California and Oregon, and is working on a monograph about the entire group—the kind of treatise that Kamp never managed to complete in his lifetime. “Sometimes I wish I could talk to him,” Schoville says. “He would have been a great colleague.”
Other researchers have also been working to tie up Kamp’s loose ends. Chris Marshall, the curator of insects at Oregon State University in Corvallis, recently described two new species from Oregon and designated a neotype to replace a type specimen of Grylloblatta rothi that Kamp never returned to Gurney. “It could be that the type specimen will turn up,” Marshall says. But designating a neotype allows science to move forward. “The goal of taxonomists is to make names work for conservationists and ecologists,” he says.
Back on our rock, we’re making ourselves a celebratory cup of hot cocoa under the grey-blue sky when Schoville informs me that it’s too soon to celebrate. To be certain—absolutely certain—that we have the right species, we need to collect an adult male so that he can examine its genitalia under a microscope, as the earlier taxonomists would have done. The rub is that males are far more difficult to find than females. “We usually get one male for every nine females we find,” he says. “It may be because the females cannibalize the males.”
The wait for dusk is painful as my toes begin to go numb and my butt is quickly losing heat on this cold rock. At 11:30 p.m., Schoville declares it dark enough to begin hunting. We put on our headlamps and scramble up a treacherous, 30-degree slope over patches of rock and snow. Within minutes, we’ve already spotted a second ice crawler silhouetted against the white snow. Another female.
All around me, though, I’m seeing the mountain come alive in ways I never anticipated. Inch-long black beetles known as Nebria—a cold-loving group which is known from the slopes of Mount Everest and the ice fields outside Juneau, Alaska—amble around looking for prey. I also see spiders and their bizarre, spindly-legged relatives known as harvestmen. Schoville finds a half-dead midge paralyzed by the cold. It’s going to be someone’s dinner.
Although ice crawlers aren’t the most charismatic creatures in the Canadian Rockies, this search somehow seems worth it. Every species—every specimen—that Schoville tallies is part of an endangered ecosystem that scientists will be watching closely in the coming decades. Ice crawlers, after all, are like living thermometers, a biological way to ground-truth the numbers that our satellites and sensors are telling us about Earth’s changes, and what their impact might be.
After two hours running around in circles and stumbling across this cobble-strewn pitch, we’ve got seven female ice crawlers in the bag. I spot Schoville’s light high up on the slope while I’m snapping photographs near our gear. He drops to his knees, and then stands back up. His headlamp swivels around and shines down at me. “I’ve got a male!” he shouts.