Mealworms are Eating Their Way to a Greener Future - and it Involves Styrofoam

Mealworms are Eating Their Way to a Greener Future - and it Involves Styrofoam


This is one of the biggest breakthroughs in environmental science in the past 10 years," 

Dr. Wu (2015 CNN Interview)

Pollution, cascading landfills, waste management catastrophes, toxins seeping into our environment – these are real problems. Finding solutions that actually work to clean our world, or to prevent trash from accumulating further, often result in less than stellar solutions or adequate proactive actions. Thankfully, Chubby knows of a super hero to solve one of these recycling nightmares. Mealworms eat Styrofoam.

We know all about who loves to eat mealworms…but did you know a mealworm’s dining desires are showing pollution solutions? Plastics are a worldwide environmental burden – tainting oceans with toxins, killing sea life and burdening shorelines. Civil and Environmental Engineer, Wei-Min Wu says that we may be able to worm our way to a resolution. "Our findings,” Wu explains, “have opened a new door to solve the global plastic pollution problem.” Wu collaborated with Professor Ju Yang and doctoral student Yu Yang from Beihang University. The study was published in Environmental Science and Technology (2015, 49 (20), pp 12080–12086).

Big news, small package

Recent findings from Stanford University and their colleagues at Beihang University have discovered that mealworms eat polystyrene. Yum. This type of plastic, the article explains, “is generally considered to be durable and resistant to biodegradation.” However, our friendly mealworm (Tenebrio molitor) larvae “chew and eat Styrofoam, a common PS [polystyrene] product. The Styrofoam was efficiently degraded in the larval gut within a retention time of less than 24 h. Fed with Styrofoam as the sole diet, the larvae lived as well as those fed with a normal diet (bran) over a period of 1 month.” 

Wow! You won’t want to feed your “feeder” mealworms Styrofoam. And if you replicate this experiment do NOT feed the plastic munchers to any animal – wildlife included! Any secondary harm possible from animals consuming the foam plastic fed mealworms is not known.

Waste from the ravenous mealworms was then analyzed.The results, not including the actual devouring of the Styrofoam itself, was nothing less than astounding (eating the actual foam was pretty astounding as well). “Within a 16 day test period, 47.7% of the ingested Styrofoam carbon was converted into CO 2 and the residue (ca. 49.2%) was egested as fecula with a limited fraction incorporated into biomass (ca. 0.5%). Tests … confirmed that the 13C-labeled PS was mineralized to 13CO2 and incorporated into lipids. The discovery of the rapid biodegradation of PS in the larval gut reveals a new fate for plastic waste in the environment.”

Over 30 million tons of plastics are dumped into the environment every year – in the US alone! This puts a modern twist on the children’s classic, The Very Hungry Caterpillar. Who could miss the fact that a simple and delightful path to taking a bite out of global pollution would rest with worms?

So how does it work?


The mealworms have gut flora that are able to break down the Styrofoam into biodegradable substances. Some of the material is converted into carbon dioxide; the rest is turned into “safe” droppings. The mealworms “degraded” the plastic in 24 hours. Left to natural decomposition, these plastics erode over hundreds of years – and the breakdown is anything but harmless. Plastics are wreaking havoc across ecosystems, especially in the marine environment, as they entrap animals and form state-sized rafts of trash known as gyres (read about the Great Pacific gyre patch ).

When animals accidentally or directly ingest plastics, the results can be fatal. Up until this study, no animal has shown the ability to actually digest the stuff. Marine birds and aquatic life are killed by plastic-induced intestinal blockages.  A 2015 study of marine animals revealed that up to a quarter of fish had ingested some form of plastic waste! These substances, if they do not kill the animal outright, slowly leech deadly substances into the fish’s body. The study, Anthropogenic Debris in Seafood, is shocking “In Indonesia, anthropogenic debris was found in 28% of individual fish and in 55% of all species. Similarly, in the USA, anthropogenic debris was found in 25% of individual fish and in 67% of all species. Anthropogenic debris was also found in 33% of individual shellfish sampled.”

Curiously, the worms fed the plastic diet were none the worse for wear. Their castings are being tested for composting possibilities, but early analysis shows the droppings are non-toxic and suitable for environmental use. While these wiggling wonders are flabbergasting scientists, it still is wise to refrain from offering the polystyrene pillagers as secondary foodstuffs!

With only 10% of plastic waste entering the recycling process, we need to take a serious look at this devastating and ever mounting situation. While mountains and sea rafts of garbage are unbelievable – they pale in comparison to the invisible carcinogenic and destructive compounds of the debris. Hopefully, as mealworm researcher Wei-Min Wu says, "Our findings have opened a new door to solve the global plastic pollution problem." 

Otherwise…we have everything to lose.

This research into mealworm digestion is trying to lead to a new way of eliminating plastic waste – that does NOT involve actual mealworms. Future studies will uncover just how those gut bacteria breakdown the foam. So far, the insect-based systems have been promising – with the mealworm study sitting at the helm of biological sanitation projects.

Earlier experiments involved another bird feeder favorite ... the waxworm. Waxworm gut microorganisms were able to digest another form of plastic called polyethylene. This is the sheet film used for bags and plastic wraps. This amazing ability led to the investigation into the darkling beetle research. If one species of larvae could eat the "impossible," what about other species? Styrofoam based plastics had proven impossible to degrade through biological methods – until the mealworms were given a crack at it.

Instead of looking at mealworms as the "special of the day"…we need to think about the insects as hungry ground breaking environmentalists. Let’s raise a toast to the mealworms and toss the cup to them- they’re hungry, hungry caterpillars.