Plastic trash is gross. These hungry caterpillars might be able to help us get rid of it.
We learn a lot by paying attention to the little things — in this case, the very little, bug-sized things.
That's what biologist and amateur beekeeper Federica Bertocchini noticed while tending to her beehives in Madrid.
To keep her bees healthy and happy, Bertocchini has to remove pests that move into the hives, including a tiny beeswax-munching caterpillar known as the wax worm.
A comb full of beeswax is a tasty meal for wax worms. Photo by Chris Hondros/Getty Images.
One day, Bertocchini was clearing out the worms, placing them in a plastic grocery bag. After working for a while, she discovered the plastic bag had developed a bunch of little holes.
The worms were eating their way out!
Plastic-eating caterpillars? Yep, they're real.
What's a freak event to one person can be inspiration to a scientist. Bertocchini decided to put the little critters to the test.
She rounded up some colleagues and gave the caterpillars more polyethylene bags to munch on. Polyethylene makes up about 40% of Europe's plastic demand. Sure enough, the caterpillars started eating through those bags, digesting the plastic, and turning it into ethylene glycol, an odorless compound found in antifreeze.
Taking a step back, Bertocchini's team said this actually makes sense. The worms normally eat wax to survive, and wax and plastic aren't that different, chemically. But this discovery could have big consequences for the environment.
A new way to digest plastic could make a difference both on land and in the ocean.
Humans love their plastic — plastic bottles, milk jugs, sandwich baggies — but unfortunately, we don't pay that much attention to what happens after we use it. Scientists estimate 4 million to 12 million metric tons of plastic enters the oceans each year.
Trash in Manila Bay in 2014. Photo from Jay Directo/AFP/Getty Images
And while ethylene glycol — what the worms are pooping out — isn't exactly great for the environment either, the substance breaks down in weeks instead of the decades or centuries that a polyethylene bag might take.
Caterpillars, bacteria, and other critters have been seen eating or breaking down plastic bags before, though Bertocchini's team said the wax worms broke down plastic faster than any other recent discoveries.
This is a really cool example of scientists learning from nature.
Though the digestion happened pretty quickly compared to other methods, it still took 100 worms 12 hours to eat through a little more than 90 milligrams of plastic. It would take those worms about a month to break down one plastic bag.
Bertocchini and her team don't yet know what exactly it is inside the wax worms that's breaking down the plastic — it might be an enzyme or some kind of gut bacteria — but once they figure that out, they might be able to supercharge the process and harness it for good.
In a news release, Bertocchini's team said they want to find a way to use this discovery to clean up our rivers and oceans. Their paper was published in the scientific journal Current Biology.
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