Stubborn Plastic May Have Met Its Match: The Hungry Wax Worm

Los Angeles Daily News/Science Section    By Amina Kahn     April 24, 2017

Here’s a caterpillar that thinks plastic tastes fantastic. Scientists have discovered that the larvae of the wax moth will easily munch through a common plastic known as polyethylene, turning it into a useful compound found in all kinds of consumer products.

The findings, published this week in the journal Current Biology, reveal an unlikely ally in the fight to reduce and reuse the enormous amounts of plastic waste that humans produce every year.

Plastic, made from oil, is the product of fossil fuels. Roughly 92% of it falls into two main categories: polyethylene and polypropylene. According to the study authors, polyethylene is widely used for packaging and so makes up about two-fifths of the plastic product demand.

Some of that plastic is recycled, but not much — out of 33.25 million tons of plastic generated in 2014, just 9.5% in the United States was recycled, according to the Environmental Protection Agency. An additional 15% was burned for energy, which is not the cleanest process, and the remaining 75.5% ended up in landfills.

“New solutions for plastic degradation are urgently needed,” the study authors wrote.

The problem is that such plastics are difficult to break down, said study coauthor Christopher J. Howe, a biochemist at Cambridge University in England. Polyethylene molecules have straight backbones of linked carbon atoms whose bonds are very stable. This means plastic doesn’t biodegrade easily in landfills, and it can form garbage patches in the ocean that pose deadly threats to marine wildlife.

Scientists have come across a few modest instances of polyethylene biodegradation, but they’re slow going. Researchers got a liquid culture of Penicillium simplicissimum fungus to break down some polyethylene — but it took three months. A bacterium, Nocardia asteroides, took four to seven months. Both appeared to produce ethylene glycol, a compound used in all kinds of products, including brake fluid, paints, plastics and even cosmetics.

This new study of the wax moth Galleria mellonella, an insect that inhabits bee hives and other places, changes that.

The discovery was something of a happy accident, Howe said: Lead author Federica Bertocchini, a developmental biologist at Institute of Biomedicine and Biotechnology of Cantabria in Spain, is a beekeper as well as a scientist. It was Bertocchini who noticed that if hive material containing moth larvae was wrapped in plastic bags, the caterpillars appeared to degrade tough plastic.

That may look like a leaf, but the wax worm is actually chewing through polyethylene plastic. (Federica Bertocchini, Paolo Bombelli and Chris Howe)Could these little caterpillars really do something that few critters are known to do?

To find out, the researchers set wax worms loose on a polyethylene film. They watched as holes appeared after just 40 minutes — at an estimated rate of about 2.2 holes per worm per hour. And when the researchers put roughly 100 wax moth larvae on a commercial shopping bag, they ate a total of 92 milligrams in about 12 hours.

Still, it was possible these wax worms were simply munching up material rather than actually digesting it into simpler products. So the scientists made a slurry of some worms and smeared the dissociated cells on polyethylene films. After 14 hours, the researchers found that 13% of the polyethylene mass had been lost — a degradation rate of 0.23 of a milligram per square centimeter.

When the researchers examined what remained of the slurry-coated plastic film, they found a signature that indicated the presence of that oh-so-useful compound, ethylene glycol — a sign that the caterpillar cells really had broken the plastic down.

How does the wax worm manage such a difficult feat, and do it with such incredible speed? It’s all thanks to the natural diet of this caterpillar, which makes its home within the honeycomb.

It’s “probably because the beeswax in the hives is similar chemically to the plastic,” Howe said. “The larvae have evolved to be able to break down the beeswax, and can break down plastic as well, given the chemical similarity.”

Beeswax is made of a wide variety of compounds, including alkanes, alkenes, fatty acids and esters. Many of those compounds include those carbon-carbon bonds — which could mean the wax moth has a natural talent for breaking those down.

So far, the scientists are not sure whether this ability is due to the wax moth larva, or to the microbes within its gut. An earlier study by a different group found that two bacterial strains taken from the gut of the Indian mealmoth could break down plastic in a few weeks (though the authors did not report seeing any ethylene glycol production).

Finding out which critter is responsible is one of the next steps in the research, Howe said.

“In the long term we'd like to use this as a basis for breaking down waste polyethylene — but there are many hurdles to be overcome in scaling the process up,” he said. “We would probably try to find the gene(s) for the enzyme(s) that are responsible, and use the gene to make lots of the enzyme in a biotechnological process rather than growing large numbers of the caterpillars.”

The Colony-Killing Mistake Backyard Beekeepers Are Making

NPR The Salt    By Dan Gunderson    August 12, 2016 

The healthy bees managed by Jonathan Garaas are checked every two weeks for signs of a possible mite infestation. Dan Gunderson/MPR News

Jonathan Garaas has learned a few things in three seasons of backyard beekeeping: Bees are fascinating. They're complicated. And keeping them alive is not easy.

Every two weeks, the Fargo, N.D., attorney opens the hives to check the bees and search for varroa mites, pests that suck the bees' blood and can transmit disease. If he sees too many of the pinhead-sized parasites, he applies a chemical treatment.

Attorney and hobby beekeeper Jonathan Garaas keeps nine thriving hives outside of Fargo, N.D. Dan Gunderson/MPR News

Garaas has lost hives in his first two years as a novice beekeeper. But with nine hives now established near his home and a couple of University of Minnesota bee classes under his belt, he feels like he's got the hang of it, although it's still a challenge.

"You can get the book learning. You can see the YouTubes. You can be told by others," he says, but "you have to have hands-on experience. When you start putting it all together, it starts making sense."

Scientists wish every beginner beekeeper were as diligent as Garaas.

While experts welcome the rising national interest in beekeeping as a hobby, they warn that novices may be inadvertently putting their hives — and other hives for miles around — in danger by not keeping the bee mite population in check.

Many hobbyists avoid mite treatments, preferring a natural approach, says Marla Spivak, a bee expert at the University of Minnesota. But that's often a deadly decision for the bees, she says.

National surveys by the Bee Informed Partnership show backyard beekeepers are taking the greatest losses nationally, and those losses are often the result of an out-of-control infestation of the varroa mite, says Spivak.

Varroa mites arrived in the United States nearly 30 years ago, and they've become a big problem in recent years.

Untreated hives can spread mites and viruses to other hives within several miles, Spivak says. Healthy bees will invade a dying hive to steal its honey. When they do, they carry the mites with them back to their hives.

University of Minnesota Bee Squad coordinator Becky Masterman secures a strap on a bee box on the roof of the Weisman Museum in Minneapolis. Judy Griesedieck for MPR News

"The combination of the mite and the viruses is deadly," says Spivak.

The University of Minnesota Bee Squad, a group that provides beekeeping education and mentoring in the Twin Cities, is seeing more healthy hives become rapidly infested with mites and the viruses they carry.

Fall is an especially critical season, says Rebecca Masterman, the Bee Squad's associate program director.

"That late season reinfestation means that bees are going through winter with a lot of mite pressure and it's really hard for them to come out of that and survive," she says. "It's important enough to really try to get every backyard beekeeper in the country to at least be aware of it."

Masterman says she's also encouraging commercial beekeepers to check their bees more often for surprise mite infestations. A new online mite-monitoring project lets beekeepers anywhere in the country share data on infestations that will help researchers track the spread.

A mite control experiment this summer should provide more information about how to best treat mites in bee colonies.

One threat to honeybees is the varroa mite, seen here invading the pupae of a developing bee. Untreated infestations will kill colonies. Judy Griesedieck for MPR NewsBees face other challenges beyond mites, including poor nutrition, disease and pesticides. Even veteran beekeepers say it takes more effort to keep their bees alive these days.

But the mite and virus threat to bees is something that can be controlled, says Spivak.

"I really understand why some people might not like to have to treat their bee colony for mites. It just sounds so awful. It's such a beautiful bee colony and to have to stick some kind of a treatment in there seems so unnatural," she says.

"But our bees are dying. And it's very important to help do whatever we can to keep them alive."

Arrest Made in Butte County Beehive Theft

7KRCR News    By Haleigh Pike    February 17, 2016

The Butte County Sheriff's Office said a man was arrested after stealing 64 beehives from Olivarez Honey Bees Inc. in Chico.

Officials said on Thursday, February 4, Olivarez Honey Bees Inc. reported that 64 beehives were stolen from a location in Chico. Officials said tire tracks left at the scene indicated that the suspect used a flatbed truck and a pull behind forklift to steal the hives. Officials added the hives were being kept behind a locked gate and the suspect cut the lock to access the area.

Butte County Deputies said on Saturday, February 6, the 64 stolen beehives were located in Stanislaus County, Ca. Officials said the hives were in the process of being rented through a bee broker to an almond grower in Oakdale, Ca. for almond pollination.

Officials said Jacob William Spath of Chico was found in possession of the beehives and was arrested by the Butte County Sheriff's Office on Wednesday, February 17 for grand theft. Officials do not believe Spath is involved in or responsible for any other beehive thefts at this time.