A global research team led by researchers from the University of Kentucky Martin-Gatton College of Agriculture, Food and Environment, has found that Antarctica's only native insect is already ingesting microplastics, even in one of the planet's most remote regions.
The study, published in the journal Science of the Total Environment, is the first to examine how microplastics affect an Antarctic insect and to document plastic pieces inside wild-caught midges.
Jack Devlin, who led the work back in 2020 as part of his Ph.D. in the before moving to Scotland to work as a marine ornithologist, said the project started after a documentary on plastic pollution left him stunned.
"Watching that film just blew my mind," Devlin said. "I started reading about plastic's effects on insects and thought, 'If plastic is turning up everywhere else, what about rare places like Antarctica?'"
A tough little midge in a changing environment
Belgica antarctica is a nonbiting midge - a small fly - about the length of a grain of rice. It is the southernmost insect on Earth and the only one found exclusively in Antarctica. Its larvae live in moist patches of moss and algae along the Antarctic Peninsula and can reach densities of nearly 40,000 per square meter, helping break down dead plant material and recycle nutrients through the soil.
"They're what we call poly-extremophiles," Devlin said. "They cope with intense cold, drying out, high salt, big swings in temperature and UV radiation. So, the big question was: Does that toughness protect them from a new stress like microplastics, or does it make them vulnerable to something they've never seen before?"
Although Antarctica is often seen as a pristine wilderness, earlier studies have detected plastic fragments in fresh snow and surrounding seawater. Concentrations are lower than in most regions, but ocean currents, long-distance wind transport and human activity from research bases and ships still carry plastics into the continent.
Putting microplastics to the test
The research team put the midges through a battery of tests, and the results were unexpected, Devlin said.
"Even at the highest plastic concentrations, survival didn't drop," Devlin said. "Their basic metabolism didn't change either. On the surface, they seemed to be doing fine."
A closer look revealed a subtle cost. Larvae exposed to higher microplastic levels had lower fat reserves, while carbohydrate and protein levels remained about the same.
Devlin believes slower feeding at low temperatures and the complex natural soil the insects live in may limit the plastic they consume. Because of the logistical challenges of working in Antarctica, the exposure period lasted only 10 days. Longer-term experiments are needed to further understand the potential impacts of microplastic exposure, he said.
Hunting for plastic inside wild Antarctic insects
The project's second phase focused on a more basic question: Are wild Belgica larvae in Antarctica already ingesting microplastics?
During a 2023 research cruise along the western Antarctic Peninsula, the team collected larvae from 20 sites on 13 islands and preserved them to prevent further feeding.
To search for plastics inside the larvae, Devlin collaborated with Italian microplastics expert Elisa Bergami at the University of Modena and Reggio Emilia and imaging expert Giovanni Birarda at Elettra Sincrotrone Trieste. The team dissected the five-millimeter larvae and analyzed their gut contents using imaging systems capable of identifying chemical "fingerprints" of particles as small as four micrometers - far below the threshold of human vision. After examining 40 larvae from across the region, they found only two microplastic fragments.
Finding just two pieces may seem minor, but Devin views it as an early warning.
"Antarctica still has much lower plastic levels than most of the planet, and that's good news," Devlin said. "Our study suggests that, right now, microplastics are not flooding these soil communities. 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."
Because the midge has no known land-based predators, any plastic it ingests likely does not travel far up the food chain. The concern, Devlin said, is what may happen if long-lived larvae continue ingesting microplastics throughout their two-year development, especially as warming and drying add additional stress.
A global problem reaching the ends of the Earth
For Devlin, the findings show how far human pollution has spread.
"This started because I watched a documentary and thought, 'Surely Antarctica is one of the last places not dealing with this,'" Devlin said. "Then you go there, you work with this incredible little insect that lives where there are no trees, barely any plants, and you still find plastic in its gut. That really brings home how widespread the problem is."
Devlin said future work will track changes in microplastic levels in Antarctic soils and test longer, multistress experiments on Belgica antarctica and other soil organisms.
"Antarctica gives us a simpler ecosystem to ask very focused questions," Devlin said. "If we pay attention now, we might learn lessons that apply far beyond the polar regions."
This work was supported by the Antarctic Science International Bursary, the U.S. National Science Foundation and the National Institute of Food and Agriculture.
Research reported in this publication was supported by the U.S. National Science Foundation under Award No. 1850988. The opinions, findings, and conclusions or recommendations expressed are those of the author(s) and do not necessarily reflect the views of the U.S. National Science Foundation.
This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch Project under award number 7000545. Any opinions, findings, conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the Department of Agriculture.
