Plastic-eating mealworms take the prize

Craig Criddle, your hypothesis was correct.

The professor and senior fellow at Stanford University predicted that one of the darling science fair experiments of 2016 would involve Darkling beetle larvae.

You remember those polystyrene-eating mealworms. They munched their way into headlines last fall for not only subsisting largely on a plastic foam diet but excreting the problem material as a waste product that appears safe to use for soil.

“There's a possibility of really important research coming out of bizarre places,” Criddle quipped at the time.

He told me how interesting it was to watch the tiny worms make meals out of chunks of foam in “little chambers” kept in the dark with some potato slices — “a little bit of good stuff” — on the side for nutrients.

“It's actually astonishing to see,” Criddle said. “I think this work will launch a thousand science fair projects.”

As the mom of a sixth grader, the passing remark stayed with me. Then, when my son had to ditch his original science fair idea because tests couldn't be done on live animals — no lab mice allowed — the mealworms came to mind. My son submitted a proposal to test the effects of caffeine on the rate of PS consumption of 800 mealworms and it was approved for the school fair at Dearborn Science, Technology, Engineering and Math 6/7 in Dearborn, Mich.

I see online that students observed the plastic-processing capabilities of mealworms all over the U.S. — from a middle school in Massachusetts to California's Pasadena High School, where a junior won a first-place medal at the 2016 Los Angeles County Science Fair. Her plastic-fed mealworms were in the category of animal physiology.

At a high school in South Dakota, two juniors were among three award recipients. The pair discovered that mealworms can digest five kinds of PS, are not toxic to predators, produce little carbon dioxide, and will eat PS over their typical diet of dried rice 80 percent of the time.

At Lester Middle School, which is on a U.S. military base on Okinawa, Japan, students also replicated the test and took it a step further by monitoring the metamorphosis of the mealworms from pupa to beetle. Their findings, which weren't disclosed by the local paper, reportedly are being submitted to Harvard University's Journal of Emerging Investigators for peer review.

My son Evan also tried to take the findings of Stanford researchers, who worked in conjunction with colleagues from Beijing University, in a new direction while satisfying his curiosity about caffeinated energy drinks. As a 12-year-old player of many sports, he's very interested in what will help and hurt his game. He got an answer early on.

About 10 percent of the mealworms convulsed and died just two days after being placed in the habitat where he brushed 20 drops of Monster Energy drink on his subjects' water source, which was a slice of apple. My son felt bad and understands better why I won't let him have those kind of beverages. After that, this group was just given plain apple and EPS in the form of the bottom of a common foam cup.

The Monster Energy survivors came in second out of the four habitats Evan studied. The group given Mountain Dew throughout the 10-day test came in last. The group that ate the most PS by far was in the smallest habitat with no oats and only PS and apple.

Like the others, my son won a ribbon for his efforts in a research area that the judges said was refreshingly different and packed with promise.

At the university level, scientists now are trying to replicate how microbes in the bugs' guts break down the plastic with enzymes that are essentially recycling the PS at a molecular level.

“The enzymes and the conditions under which the enzymes are operating are key,” Criddle had told me.

In the meantime, the researchers have inspired a new generation to follow their work and try to advance it. The big hope is that scientists are on the brink of engineering enzymes to degrade a kind of plastic that sits in landfills for hundreds of years. Or, maybe they can help manufacturers design polymers that don't accumulate in the environment or food chains.

I'm just heartened to know that so many tweens and teens are genuinely interested in working the bugs out of this plastic problem.