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Wax Worms Have a Voracious Appetite—for Plastic Bags

Let’s hope these caterpillars are very, very hungry.

Lunch time.
Lunch time. César Hernández/CSIC

Plastic is pretty much forever. That polyethylene plastic bag you used to bring your groceries home can last for centuries in a landfill or the ocean. Scientists have tried using bacteria and fungus to break down plastics, but a team of researchers in the England and Spain have shown that a humble larva might be a much better fit for the job.

Frederica Bertocchini, a biologist at the Institute of Biomedicine and Biotechnology in Spain, noticed some wax worms had managed to eat their way through the plastic bags they were being kept in. While other organisms can take weeks or months to break down even the smallest amount of plastic, the wax worm can get through more—in a far shorter period of time. The researchers let 100 wax worms chow down on a plastic grocery bag, and after just 12 hours they’d eaten about 4 percent of the bag, according to findings published Monday in the journal Current Biology. That may not sound like much, but that’s a vast improvement over fungi, which weren’t able to break down a noticeable amount of polyethylene after six months.

Wax worms chew their way to freedom.
Wax worms chew their way to freedom. César Hernández/Ainhoa Goñi

It’s not just that the wax worms are particularly efficient chewers. Bertocchini’s team spread some wax worm guts on plastic and found that ate through the plastic, too. The worms produce an enzyme that can break down the plastic—into ethylene glycol, which can be used to make polyester or antifreeze—so a next step for scientists will be isolating that chemical.

Munching on plastic isn’t that big of a change in diet for wax worms. Wax moths, their adult form, usually lay their eggs in beehives, and newly hatched larvae eat their way through beeswax. “Wax is a polymer, a sort of ‘natural plastic,’ and has a chemical structure not dissimilar to polyethylene,” Bertocchini said in a press release. Hopefully the wax worm’s special skills can help us do something about the billions of plastic bags thrown away every year.