Appetite for destruction: The caterpillars which devour plastic

The answer to the plastic peril facing the world could be a humble caterpillar - and the discovery was a complete accident.

The wax worm, the larvae of the wax moth, could prove to be an important weapon in the fight to reduce plastic waste clogging landfills and waterways.

Each year, it's estimated New Zealanders alone use around 1.6 billion single-use plastic bags, with around 40,000 sent to landfill every hour, according to evidence presented to a Parliament select committee last year.

The bags also take a long time to break down - from anywhere between 20 to 1000 years.

But now researchers from Spain and the UK have documented a new addition to the wax worms' diet.

"We have found that the larva of a common insect, Galleria mellonella, is able to biodegrade one of the toughest, most resilient, and most used plastics: polyethylene," says Federica Bertocchini of the Institute of Biomedicine and Biotechnology of Cantabria in Spain.

It wasn't even what the researchers wanted to study.

The wax worm chowing down on a plastic bag (Paolo Bombelli / Supplied)
The wax worm chowing down on a plastic bag (Paolo Bombelli / Supplied)

It was only when the larvae, which were being transported in a plastic bag, chewed holes through it and escaped that they cottoned onto the possible pollution solution.

They found the worms not only eat the plastic, they break it down chemically into the organic compound ethylene glycol.

They're hungry caterpillars too, doing noticeable damage to the plastic bags in less than an hour.

Plastic isn't part of their normal diet, but the researchers think their appetite for it comes from their natural surroundings.

Wax moths lay their eggs inside beehives where the worms eventually hatch and devour beeswax which could involve breaking down similar kinds of chemical bonds.

"Wax is a polymer, a sort of 'natural plastic,' and has a chemical structure not dissimilar to polyethylene, Ms Bertocchini says.

However, the researchers say this needs more investigation.

She says the team will now work on putting the worms to work in getting rid of plastic waste to help further reduce the amount of rubbish which enters the environment.

But Ms Bertocchini warns this discovery isn't an excuse to use more plastic "just because we now know how to bio-degrade it".

The study was published in Current Biology.

There have been a number of online petitions circulating around New Zealand calling for the phasing out of plastic bags.

Green Party MP Denise Roche has a proposed member's bill which would see customers pay for single-use plastic bags, the money from which will go back to the Government for waste minimisation schemes.