Antarctica’s Only Bug Is Eating Something It Really Shouldn’t

To survive the bitter cold, Antarctica’s native residents adorn themselves with thick layers of fat and fur. A non-biting midge, on the other hand, has only a soft shell to shield itself—but that perhaps speaks to how tough the region’s sole native insect species is, researchers say. For one, it appears capable of digesting microplastics.

Belgica antarctica is a small fly roughly the size of a grain of rice. The insects typically reside within moss and algae, breaking down dead plant materials and recycling nutrients throughout the frozen soil. But a recent study, published in Science of the Total Environment, discovered the presence of microplastics inside midges, hinting at a concerning increase in the pollutant in one of Earth’s most remote regions.

“Antarctica still has much lower plastic levels than most of the planet, and that’s good news,†said Jack Devlin, study lead author and an entomologist at the University of Kentucky, in a statement. “But we can now say they are getting into the system, and at high enough levels they start to change the insect’s energy balance.â€

“A tough little midgeâ€

The experiment was partly inspired by earlier work that detected plastic fragments in Antarctic snow and seawater, which came from human activity in research bases and ships. Given their decomposer lifestyle, researchers wondered whether midges would also be exposed to microplastics.

“They cope with intense cold, drying out, high salt, big swings in temperature and UV radiation,†explained Devlin. “Does that toughness protect them from a new stress like microplastics or does it make them vulnerable to something they’ve never seen before?â€

The project was done in two phases. First, at the lab, researchers exposed the midges to different amounts of microplastics for 10 days, tracking any changes in the insects’ health. Surprisingly, the insects’ metabolism didn’t change all that much, and on the surface, “they seemed to be doing fine,†Devlin said.

The only time the midges actually consumed the microplastic beads was at the highest concentration levels, the paper added. Even then, survival rates didn’t drop, although younger larvae in the experiment weren’t able to reserve as much fat.

Plastics in the South Pole

Then, the team set out for field experiments in Antarctica, during which they collected midge larvae from 20 sites on 13 islands. Back at the lab, they dissected the larvae—tiny creatures measuring about 0.2 inches (5 millimeters)—and analyzed their gut contents for any plastic signals. Of the 40 larvae examined, the team found only two microplastic fragments.

“Our study suggests that, right now, microplastics are not flooding these soil communities,†Devlin noted. But this should be an “early warning†that microplastics are slowly infiltrating Antarctica, he said.

That said, midges don’t have any known land-based predators, meaning that any plastic they ingest is unlikely to spread throughout the food chain. It is also not known yet how microplastics will affect larvae in the long run, as environmental constraints placed limitations on how long the researchers’ experiments could be, according to the paper. But there should be continued interest, Devlin said.

“Antarctica gives us a simpler ecosystem to ask very focused questions,†Devlin added. “If we pay attention now, we might learn lessons that apply far beyond the polar regions.â€

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