Used as fish bait or exterminated as parasites from beehives, waxworms haven’t gotten a lot of love in the past. When they aren’t being bred as bait or pet food, the larvae of the wax moth hole up in bee colonies, where they munch on everything from bee cocoons to pollen to beeswax. They’re a pest, especially in Europe, and when Federica Bertocchini cleaned them out of her beehives, she wasn’t looking for a scientific breakthrough. However, when she left the worms in a plastic bag and returned an hour later, that’s exactly what she found.
Specifically, she found that the waxworms had chewed holes through the bag. As a developmental biologist, Bertocchini suspected that something amazing had happened, and began to investigate further. In a series of experiments, Bertocchini and entomologists from Cambridge put waxworms on polyethylene plastic. Like the beeswax the worms usually ingest, plastic is a polymer and both have a similar carbon structure. Overnight, they were able to destroy 92 milligrams of the bag. Given that rate, 100 waxworms would be able to break down an average-sized plastic bag, or about 5.5 grams, in one month.
One concern the scientists had was that the worms might not actually be destroying or eating the bag, but just chewing it down into tiny pieces that the human eye can’t see. If this was the case, the plastic waste wouldn’t truly be reduced; just smaller. To answer this question, scientists squished some of the worms into a paste, and rubbed it on the plastic bags. The enzymes in their bodies undamaged, the wormy paste was indeed able to still create holes!
This is a huge discovery that could provide a way to reduce plastic pollution. Every year, a single person is responsible for tossing out more than 200 plastic bags, which can take between 100-400 years to disappear from the environment. On a global scale, humans produce 300 million tons of plastic, which kill ocean and land wildlife like seabirds. On land, a single bag can kill one animal every three months. Since animals can’t break down the bag in their digestive system, the plastic will continue causing deaths for as long as it exists in the environment. Bags also disrupt the flow of waterways and affect the nutrient level in soil.
While more and more states and countries are working to ban the use of plastic bags, the ones we’ve thrown out in the past aren’t going anywhere, and only 1% of plastic bags end up being recycled. Now, with waxworms, maybe we have a chance to reduce pollution. Scientists are hoping to pinpoint the exact enzyme that causes the breakdown. The dream is to inject these genes into other organisms, like bacteria or phytoplankton, and use them to reduce plastic pollution.
It will probably be a long time before we see plastic-chomping bacteria however, since there are very strict rules about releasing organisms that have been genetically-modified. For now, we could breed waxworms specifically for plastics, though further tests are needed to find out if the worms will stop munching plastic at some point, or just keep eating bags for as long as they are there.