Plastic Munching Moths May Be the Next Step in Pollution Mitigation

You've heard of garbage-eating wigglers and microbes that clean up wastewater from wineries: Mother Nature's own little helpers in combating pollution. Now we bring you moths that crunch through plastic.

Actually, to be fair to its larvae, credit should go where credit is due: Its the insect's sleek-looking worm-like caterpillars that are getting all the attention these days, proving that Nature, when called upon, has ways to clean up humans' detritus.

And in this case, it's a huge find. Scientists are already imagining how this incidental discovery can help get rid of the tons of material that has stumped scientists for eons when it comes to cleaning up ocean gyres and local landfills. More than 90 percent of the plastic found in landfills comprise either polyethylene or polypropylene, the two plastics that are the most difficult to dissolve. Efforts to develop a bacteria that could disintegrate the plastics haven't gone as well as hoped.

So it was a lucky chance when biologist and beekeeper Dr. Federica Bertocchini of Cantabria University, Spain, happened to cart a bunch of greater wax worms to her house after finding them in and around her beehives. Wax worms are the scourge of beehives and Bertocchini knew that she had to identify them to be sure. She placed them gingerly in a plastic shopping bag and headed back home. By the time she was able to retrieve them from the bag, the insects had escaped, making themselves at home in her house. She looked at the hole-ridden plastic bag and had an ah-hah! moment.

Realizing she might be onto a way to degrade these two plastics, she joined up with two other biochemists, Paolo Bombelli and Christopher Howe of Cambridge University and went to work to test the insects' capabilities in greater detail. Her two colleagues already knew that there's a molecular similarity between beeswax and these plastics and that likely, that's why the wax moth caterpillar was able to chew through its confines.

What was encouraging was that it took the caterpillar relatively little time to break down the molecular "bridge" that held the plastic together and gain freedom. That means that left to their own devices in a rubbish heap of plastic, the little caterpillars might actually be able to break down the polyethylene in the same way they ingest beeswax.

But that isn't exactly the result that the scientists are hoping to produce. Their aim, said Bertocchini in a recent interview, is to find a way to simulate the caterpillar's method of ingestion. In other words, to discover what Bertocchini refers to as the  "molecular devices responsible for this effect."

The scientists aren't convinced that that the insects were chomping through the plastic because they were hungry. Rather, it might have been simply to gain freedom. So the most logical step forward, said Bertoccini, is to simply put, figure out how the critters did it.

"In the past few years, and even more in the past year, the issue of plastic pollution, or pollution in general, has been discussed more and more. In my opinion, given the dramatic situation of our planet, talking about climate change, pollution and similar matters is never enough, they should talk more and push more, generally speaking," Bertoccini said.

The research was published in the April 2017 edition of Current Biology.

Flickr image: Andy Reago and Chrissy McClaren