Mealworms’ Fascinating Feast

The Sophia M. Sachs Butterfly House celebrates “all things creepy and crawly” every October as it transforms into the BOOterfly House, with a Scorpion Lair, Botanicals Gone Mad, and spectacular spiders.  One special insect introduced last year will be making a return this October; the mealworm.

Mealworms are darkling beetle larvae that are widely cultivated as a feeder insect for bearded dragons, bluebirds, chickens, fish, and many more pets, but it is what the mealworms are able to eat that has made them a valuable member of the BOOterfly House cast.

That food is styrofoam, a non-biodegradable material. The discovery of wax worms’ ability to ingest this commonly discarded material occurred in Europe.


The rather muscular and chiseled form of an introduced pest of bees nests, the wax worm. (Photo by Wayne Boo)

After removing a few wax worms from her beehives and placing them in plastic bags, Spanish National Research Council scientist Federica Bertocchini later discovered that the worms had chewed holes through the bags. Bertocchini contacted peers at the University of Cambridge, where study of wax worms’ eating habits began in earnest.

The case of wax worms and polyethylene lead scientists to begin testing what other types of plastics other worms could possibly digest, including the mealworm.

“Mealworms will eat almost anything,” explains Tad Yankoski, Butterfly House entomologist. “They tend to prefer starchy things such as corn, oats, and wheat.”

What enables them to break down the hydrocarbon chains in starchy foods, and also styrofoam, is the bacteria in their gut.  This bacteria exists in a symbiotic relationship with the mealworm, their host, in a manner similar to how bacteria and microorganisms exist symbiotically in cow guts.

As detailed by Yale Scientific, mealworms excrete around half of the carbon in styrofoam as carbon dioxide gas, with the remaining percentage of carbon is excreted in their waste.  That waste can be used as agricultural soil, showing that it is both biodegradable and useful.

More research is still being done on how the bacteria in mealworms’ guts could be replicated and genetically altered.

Simply dumping mealworms into landfills isn’t a feasible large-scale solution for the world’s problem of plastic waste because 100 mealworms digest about 37 milligrams of styrofoam per day and Americans dispose of about 33 million tons of styrofoam each year.

“One possibility is culturing the gut bacteria and bioengineering it to break down microbeads, which are polluting the world’s oceans,” adds Yankoski.

For now, however, these hungry haunt the BOOterfly House throughout October.
Morgan Niezing
Digital Media Intern

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