A Newbie in Denali

Over the short Alaskan summer of 2012, Jessica Rykken conducted the first detailed inventory of Denali National Park and Preserve’s pollinators. Armed with butterfly nets, Rykken, park staff and volunteers scooped up bees from alpine meadows, roadsides and river banks. They also trapped insects in brightly colored plastic bowls and jars full of soapy water. In all, Rykken and her assistants gathered 552 bees and hundreds more flower flies.

Then Rykken, who has since become the park’s entomologist, went about identifying the bees — most of them bumblebees — that she had caught. First, she washed the bees, which she had stored in alcohol, with warm water and a little bit of detergent. Next, she used a regular hair dryer to restore each one to its fluffy self. After carefully examining each specimen under a microscope, Rykken identified 20 separate bee species, including 13 bumblebees. She hesitated when labeling a few bumblebees as Bombus neoboreus, a species found in the arctic tundra of Alaska and Canada: “There were several specimens of neoboreus that didn’t look quite right,” she said. Rykken made a note of the discrepancy, and after pinning each bee, she took boxes of labeled bees to Derek Sikes, the insect curator at the University of Alaska Museum in Fairbanks, where they became part of the museum’s collections.

Four years later, while reading a scientific paper that Sikes had emailed her, Rykken learned that she had contributed to a major discovery. Those funny-looking neoboreus bumblebees? They were actually members of a species new to science. “The last bumblebee species discovered in North America was 90 years ago, so it’s a pretty big deal,” Rykken said.

Paul Williams, a bumblebee expert at the Natural History Museum in London, first suspected the existence of a new species in 2008, when he noticed that some black-tailed neoboreus bumblebees had slightly unusual body shapes and hair lengths. He later came across two similar bumblebees collected in Canada’s Yukon in 2010 and asked that their DNA be sequenced as part of a global effort to create a reference library of the world’s 20,000 or so bee species. Williams found that the Yukon bees’ DNA differed from that of any other known species. Looking for confirmation, he asked colleagues across North America to send him black-tailed neoboreus bees from their collections. After examining thousands of bumblebee specimens, Williams eventually struck gold: Three of the bees that Rykken had collected in Denali proved to be a match.

The formal description of a new species needs to include the bee’s physical characteristics and explain how the defining traits are different from those of similar species. That’s particularly difficult for bumblebees because different species that live in the same environment often end up resembling each other through a phenomenon known as mimicry. What’s more, the same species of bumblebees can exhibit different color patterns in different parts of its range, which has led entomologists to erroneously identify bees with hair color variation as separate species. “That caused a lot of confusion,” Williams said.

And so, with the DNA evidence in hand, Williams set out to examine the morphology of the newcomer and compare it with its closest relatives. Using a graticule — a network of measuring lines on a microscope eyepiece — he found that the new species looked very much like B. neoboreus but had consistently longer cheeks, a trait that is sufficient to distinguish the two species. Not much else is known about the new species, and so far, it has been found only in Denali and in the Kluane region of Canada near the Alaska border. Williams and his colleagues named the new bee Bombus kluanensis.

A new long-cheeked bee on the block may not seem like much, but it’s cause for celebration. Commercially raised honeybees have experienced substantial declines in recent years, which experts fear could have a devastating effect on some crops. Scientists have suggested that native bees could pick up the slack, but those bees aren’t faring much better. In early 2017, the rusty patched bumblebee, now present in only 0.1 percent of its historical range, became the first bee species in the continental U.S. to be listed as endangered. Franklin’s bumblebees used to buzz around southern Oregon and Northern California but have not been seen since 2006 and may well be extinct.

Habitat loss is the main culprit, but other factors such as pesticides and pathogens carried by non-native species also contribute to the decline of bumblebees, Williams said. And then there is climate change. A study of bumblebees in North America and Europe found that unlike butterflies, bumblebees haven’t been able to compensate for the shrinking of their range in the south by expanding into more northern territories.

Rykken’s work in Denali contributed to a coordinated survey of native bees in nearly 50 national park sites with landscapes — from alpine meadows to deserts and coastal dunes — that are particularly vulnerable to climate change. The researchers found, for instance, that dune-dwelling bees move fairly easily along the coast as sands shift, but the bees will have nowhere to go if their ecosystem is submerged by rising seas. “If there are no dune systems, then a whole series of bees disappears,” said Sam Droege, a biologist at the U.S. Geological Survey who supervised the inventory.

In the Alaskan interior, winter temperatures have increased more than 6 F since the 1950s. As a result, glaciers are shrinking, the permafrost is thawing, shrubs are encroaching on the arctic tundra, and invasive species are finding the climate more suitable. To monitor the effect of a changing climate on local insect populations, scientists must first determine which species live there. Since Sikes joined the University of Alaska Museum staff in 2006, he’s been on a quest to document every one of the state’s non-marine arthropods. “The climate is changing faster than in the lower 48,” Sikes said. “That’s why there is a rush to get this work done.”

Denali’s bumblebees are well equipped to handle the cold. Their fur insulates them, and they can shiver to regulate their body temperature. They’ve even been observed foraging during snowfalls. How B. kluanensis and the park’s other bumblebees will fare in warmer temperatures is unknown, but Rykken and others will continue to keep an eye on them because they know how important bumblebees are to Denali’s ecosystems. For one thing, bumblebees are the main pollinators of blueberries, which, by late summer, are one of the few foods Denali’s grizzlies eat.

“Without bumblebees in Denali, there wouldn’t be any grizzly bears,” Rykken said. “We go to parks to see the charismatic megafauna, but the species that support them are these tiny creatures.”