Are Hungry Caterpillars The Key To The World’s Plastic Problem?

Recent research by scientists has uncovered an unlikely solution to the world’s massive plastic waste problem – caterpillars. The study, conducted by a team at Canada’s Brandon University led by Christophe LeMoine and published yesterday in the journal Proceedings of the Royal Society B, found that 60 waxworms were able to munch their way through 30 sq cm of polyethylene in a week.

Polythene, the kind of plastic most disposable carrier bags are made from, is one of the most widely used plastics in the world. The substance is a major contributor to the 50 million tonnes of plastic debris found in the world’s oceans in 2015. That, according to a report published by the government last year, is set to rise to a huge 150 million tonnes by 2025.

Using living organisms from bacteria to fungi to alter or break down the resilient chemical structures of plastic polymers is one option being explored. And it looks as though hungry caterpillars could be the most promising of the lot.

Waxworms are the larvae of the greater wax moth. The research by the Canadian team indicates the caterpillars, or potentially just the kind of bacteria in their gut that means they can live on polythene, could be set to work breaking down in days plastics that would ordinarily takes centuries to decompose.

In their natural, wild habitat, waxworms burrow their way into bee hives and eat the beeswax of the honeycombs. The kind of thin polythene that disposable carrier bags are made from has a similar molecular structure.

It’s still not entirely clear how the microbes in the digestive tract of the caterpillars work in tandem with the rest of the organisms to break down beeswax and plastics. But it is hoped that further research will uncover the secret. One challenge is likely to be that the waxworms excrete toxic ethylene glycol after consuming polymers, which would have to be disposed of.

Dr LeMoine explained:

“There appears to be a synergy between the waxworm and its gut bacteria that accelerates plastic biodegradation. A better understanding of how this works may guide future efforts to design the ‘perfect’ plastic biodegradation system.”