By: Jovia Zhang

In early June, scientists from the University of Queensland in Brisbane, Australia discovered that the larva of a darkling beetle is able to eat Styrofoam. They concluded that the two-inch-long superworm might be able to help reduce the amount of polystyrene, or Styrofoam, in landfills.

Styrofoam trash accounts for as much as 30 percent of landfill space worldwide. Researchers have found that this material can take up to 500 years to break down and decompose. Chris Rinke, who led a study published in the journal Microbial Genomics, revealed that previous reports had shown that waxworms and mealworms – also beetle larvae – have performed well when it came to eating plastic, “so we hypothesized that the much larger superworms can eat even more.”

While most people might expect the larvae to perish as a result of eating Styrofoam and other plastics, they actually gained a bit of weight and most of the time were able to metamorphose into beetles successfully. In fact, darkling beetle larvae actually gained energy from consuming Styrofoam.

But when fed antibiotics, mealworms and superworms lost this special ability to successfully digest plastics. Therefore, researchers have concluded that worms’ gut microbiomes are likely helping them digest these humanmade substances. (Apparently, antibiotics killed the microbiomes in the worms’ digestive tracts.)

In order to analyze those microbiomes, Dr. Rinke and his research team fed the superworms three different diets. One group was given bran, a second was given polystyrene, and the third group ate nothing. Although the bran was more popular amongst the superworms, they were willing to try the polystyrene as well.

By the end of the study, nearly 93 percent of the bran group completed the worm-to-beetle transition successfully, while only 10 percent of the superworms who starved did. Strikingly, 66.7 percent of the polystyrene group were able to successfully transition. Scientists concluded that, while polystyrene is not necessarily a healthful food for superworms, they can survive consuming it.

In an article published in The New York Times, journalist Veronique Greenwood wrote, “The researchers sequenced all the DNA they could extract from the guts of the larvae. They were less interested in which specific microbes were present than in what enzymes were being made as a handful of likely candidates – all types of enzymes known for their slicing-and-dicing abilities – that were possibly shearing polystyrene down into smaller pieces.”

Despite the findings from Rinke and others, there are many reasons why none have made it into the recycling industry over the past decade. In an article for The Washington Post, Andrew Ellington, a professor of molecular biosciences at the University of Texas at Austin, said, “When you find something on a beach or you find something in a worm gut, that’s great, but all the enzymes in that thing work pretty much under the condition where you found it. And those may not be industrial conditions.” Even if researchers decided to flood landfills with Styrofoam-eating worms, separating Styrofoam from other trash would be inconvenient and costly.

In an article for Science Alert, journalist Issam Ahmed wrote, “But while breeding more worms for this purpose is possible, he [Rinke] envisages another route: creating recycling plants that mimic what the larvae do, which is to first shred the plastic in their mouths then digest it through bacterial enzymes.”

Sources:

https://www.washingtonpost.com/technology/2022/06/17/plastic-eating-superworm-garbage-crisis/

https://www.sciencealert.com/styrofoam-munching-superworms-could-lead-to-plastic-upcycling