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“When I gently poked them, the spiders moved,” says Dr. Davies. “If an insect or spider is active in winter, that usually means it has some kind of antifreeze.”

Dr. Davies and Queen’s researcher (Biomedical and Molecular Sciences) have spent decades studying antifreeze proteins in insects and fish. These proteins prevent ice crystals from growing inside the body, which would otherwise be fatal.

Spiders were known to have antifreeze activity as far back as the late 1970s. What had never been done was to identify the protein itself and understand how it works.

“That was the missing piece,” says Dr. Graham. “No one had taken the next step to look at the structure and behaviour of the spider antifreeze.”
 

A protein that stops ice cold

To study the spiders, the team partnered with Czech researcher Dr. Stanislav Pekár, who studies winter-active spiders in European orchards. Live spiders cannot be shipped across borders, so the specimens were freeze-dried before arriving in Kingston.

From there, the work moved into the lab.

“We literally start with a spider slurry,” says Dr. Graham. “Then we purify the antifreeze protein using ice itself.”

The process relies on the protein’s defining feature. Antifreeze proteins stick to ice, while other proteins do not. By repeatedly freezing and melting the sample, the team was able to isolate the antifreeze protein in pure form.

Under the microscope, the effect was dramatic.

“With no antifreeze, ice grows as you cool it,” says Dr. Davies. “With this protein present, the ice just stops growing.”

The spider antifreeze was classified as “hyperactive” because it works far more efficiently than antifreeze proteins found in fish. While fish only need protection down to about minus two degrees Celsius, land-dwelling insects and spiders can face temperatures below minus 30.

“These spiders need something much more potent,” says Dr. Davies. “And that’s exactly what they have.”
 

A new fold, evolved from scratch

The study also revealed that the spider antifreeze protein has a unique shape, known as a beta-solenoid fold. While it shares some functional features with antifreeze proteins in insects, it is structurally distinct.

Rather than allowing ice to form inside the body, the protein acts early, blocking ice crystals at the moment they begin to grow. The spiders also produce several slightly different versions of the protein, known as isoforms. Working together, these versions interfere with ice growth in multiple directions, making freezing far less likely.

“That mix seems to work better than a single version,” says Dr. Davies. “It’s nature using a team approach.”
 

Spiders as winter pest control

Beyond survival, winter activity gives these spiders an ecological advantage. In orchards, Clubiona spiders remain active when insect pests are dormant and vulnerable.

“Spiders are among the most important natural enemies of orchard pests,” says Dr. Davies. “If they can hunt all winter, that’s a big benefit.”

The research supports the idea that protecting spider populations could reduce the need for pesticides, especially if growers use products that target insects without harming spiders.

Dr. Graham adds that spiders often go unnoticed because they work quietly in the background. “If you see spiders around, it usually means they’re doing something useful,” she says.
 

Why evolution keeps repeating itself

One of the most intriguing findings is how often antifreeze proteins have evolved independently across the animal kingdom.

“We see this again and again,” says Dr. Davies. “Fish, insects, spiders. Different proteins, same function.”

The repeated evolution suggests that extreme cold has been a powerful force shaping life on Earth, especially during past ice ages. It also highlights how energy-intensive antifreeze production is, with organisms only maintaining it when they truly need it.

As the climate warms, that balance may shift.

“If the ice disappears, the selective pressure disappears too,” says Dr. Graham. “Producing antifreeze takes energy, and evolution doesn’t waste energy.”

For now, though, winter-active spiders continue their cold-weather work, quietly patrolling orchards and backyards alike.

“Don’t squish them,” says Dr. Davies. “They’re on our side.”