Life in the Cold Lane: Study Sheds New Light on Beetle Biodiversity in the Sub-Arctic

A member of the predaceous diving beetle family Dystiscidae (image by Evanherk)

The Canadian Arctic is undergoing dramatic environmental change, and researchers from Guelph are at the forefront of an effort to map this world before it warms up.

While most of us associate Arctic and sub-Arctic ecology with pictures of polar bears on ice floes, there is an abundance of smaller-scale life that is just waiting to be explored. Samantha Majoros, a master’s student working with Dr. Sarah Adamowicz in the Department of Integrative Biology, is on a mission to find out more about one such group: beetles.

“Beetles are really diverse and have a lot of different characteristics,” says Majoros, “and I was always interested in species that could survive in environments that were more challenging—like the Arctic.”

The Arctic’s extremely harsh conditions are thought to filter out species that don’t have the right traits to survive. Majoros wanted to know whether this kind of process occurred in beetles by comparing communities from Churchill, Manitoba, with those found in Guelph, Ontario.

Majoros mapped the ancestral relationships between beetle specimens into what biologists call a “tree of life.” First introduced by Darwin, the tree of life is a metaphor for the branching that occurs when species evolve and diversify over long periods of time.

Using publicly available barcoding data—which identifies species by their unique genetic sequence, like barcodes on products—Majoros combined Darwin’s tree of life concept with modern techniques.

“We used the Barcode of Life Data Systems,” says Majoros, “an international database that provides a really valuable source of information for researchers. There is abundant data on the beetles found in Churchill.”

In addition to inferring ancestral relationships for beetle species, Majoros assigned habitat and diet traits to each beetle family depending on whether they were aquatic or terrestrial, and fed on prey, plants, or fungi.

Some of the results were surprising.

“The predaceous families were more clustered in Churchill,” explains Majoros, adding that this may be because plant life there is less diverse than in southern Ontario.

A second unexpected finding was that, of all the beetle species found across Canada, aquatic families were overrepresented in the sub-Arctic region compared with terrestrial ones.

“This would suggest that something about living in water makes aquatic beetles better able to cope with the extreme conditions found in the Arctic,” says Majoros.

This work helps us plan for the future in a warming world, but it also shines a light on how the sub-Arctic was colonized in the first place, after the last Ice Age ended around 8,000 years ago.

“Seeing that certain traits are associated with some sub-Arctic areas suggests that the colonization of the region wasn’t random,” notes Majoros, “but rather that it was influenced by the characteristics of the colonizing species.”

Describing life in the far North, from small insects to large mammals, is crucial, says Majoros.

“Our Arctic environment is under some of the most intense threats from climate change. The more we know about what species are found in the Arctic and how they live, the better our chances of understanding how the whole ecosystem might change.”

Adamowicz further points out that she and Majoros were inspired to pursue this work by participating in the University of Guelph’s Arctic Ecology field course, which takes place in Churchill. “Experiential field components play an important role in setting up interactions with research in the department,” says Adamowicz.

Perhaps we can be a bit more like Majoros’s personal favourite, the Dytiscidae family of diving beetles, and plunge headfirst into rapidly warming Arctic waters to see what else we can learn about this fascinating ecosystem before it changes forever.

This study was funded in part by the Natural Sciences and Engineering Research Council.

Read the full study in the journal Ecology and Evolution.

Read about other CBS Research Highlights.