利用苍蝇制造食物

AUDIE CORNISH, HOST: From NPR News, this is ALL THINGS CONSIDERED. I'm Audie Cornish.

ROBERT SIEGEL, HOST: And I'm Robert Siegel. One of the great challenges facing our world is how to grow more food without using up the planet's land and water. And one of the most innovative solutions involves insects. Not our eating insects. The idea is farming insects that would become feed for fish or for pigs. NPR's Dan Charles explains how it works.

DAN CHARLES, BYLINE: In the quirky little college town of Yellow Springs, Ohio, home to many unconventional ideas over the years, there's now a small insect factory. It's a generic boxy building in The Millworks, a miniature industrial park. You have to search to find the company's sign. It says, Enviroflight.

GLEN COURTRIGHT: At least it's not Bug Tech.

CHARLES: That's the man who set up this company, Glen Courtright. Our tour starts with a small greenhouse.

COURTRIGHT: Well, this is where we propagate our species. Sometimes we call this the Love Shack.

CHARLES: I see rows of tall cages. And flying around inside them, or sitting on the walls, are some black insects that look a little like wasps. Actually, they're flies - black soldier flies. These flies live all over the American South, but they rarely bother people. Adult soldier flies are shy creatures. They can't bite. They can't eat. All they really do is reproduce and that's what they're supposed to be doing here.

COURTRIGHT: And, in fact, you could look here in this one.

CHARLES: Right here?

COURTRIGHT: They're kind of tail to tail. They're mating. So for us, that's money in the bank.

CHARLES: Females then lay eggs and eggs turn into tiny hatchlings. They look like dust at first. In the nursery, they grow a mass of wriggling larvae. Enviroflight's Kimberly Wildman keeps them in stacks of shallow buckets.

KIMBERLY WILDMAN: If I was to feed them, this would feel like the bucket was practically melting.

CHARLES: Really?

WILDMAN: Yes.

CHARLES: They give off that much heat?

WILDMAN: They give off that much heat.

CHARLES: And they eat like crazy, twice their weight every day, turning it into high quality protein. These larvae will eat almost anything and this is the key to Glen Courtright's business. These black soldier fly larvae are the world's greatest waste recyclers.

COURTRIGHT: We make stuff go away.

CHARLES: Right now, his building is full of larvae feeding on waste from an ethanol plant. He's always fed them brewer's grain, what's left over from making beer. Even better, he says, will be the scraps from a chicken nugget plant. These factories put out millions of pounds of chicken bits, bread crumbs and oily sludge every year.

Or dream even bigger. Think of slaughterhouses. Americans only eat 50 percent of a cow or a hog. The rest goes to industrial rendering plants. But black soldier fly larvae could happily eat that, too. Courtright shows me a new experiment. He's turning the larvae loose on some leftover bits of chicken.

COURTRIGHT: The bugs consume the material. Probably 90 percent of the material is consumed, and all that's left is a little bit of bone and sinew and fur.

CHARLES: Whatever they eat, all the insect larvae in this building grow fat and then they go into a commercial oven.

COURTRIGHT: So what we have here is cooked, dehydrated, insect larvae. And it kind of tastes like a savory cracker without salt. They're not bad.

CHARLES: You've tasted them?

COURTRIGHT: Oh, yeah, I've tasted them. You want to taste them?

CHARLES: No, not really.

COURTRIGHT: Okay, here, I will.

CHARLES: He pops a handful of them into his mouth.

COURTRIGHT: Not bad.

CHARLES: Honestly, though, Courtright has no ambitions to sell snack food. The goal here is to turn these larvae into animal feed. This protein is just what young piglets need, for instance. The ground-up larvae also could replace some of the fish meal that's used to feed salmon or trout. Right now, that fishmeal is manufactured from sardines and anchovies and menhaden.

COURTRIGHT: We have ships that are just sucking these fish out of the ocean.

CHARLES: Basically, the way Courtright sees it, these larvae solve two enormous problems at once: the waste problem and the food supply problem. Now this is not a totally new idea. Craig Sheppard, an insect specialist now retired from the University of Georgia, has been doing experiments with black soldier flies for a couple of decades now.

He's turned the little larvae loose on animal manure. They clean it up quite nicely. And over the years, he and his colleagues have talked to some companies about how to turn this into a real business.

CRAIG SHEPPARD: The guys would come down here and get real excited. They'd look at our production, and we'd say how we could ramp it up, and they would be walking away just grinning and high-fiving, like yeah, we gotta do this. And then they'd go home and talk to the higher-ups. And I just can imagine the conversation being like, well, you know, maggots? Really? And they'd back off.

CHARLES: Maybe it seemed just a little too weird. Something you'd be laughed at for trying. But a number of people, not just Glen Courtright, are picking up this idea again. What's changed is the demand for animal feed. Fish meal prices have gone through the roof. Feed for pigs is more expensive, too. Across the world, there's competition for land, for crops, for food.

Courtright thinks that competition will only grow.

COURTRIGHT: We have a protein deficit. And we have 7 billion people on the planet, we're heading for nine. We don't know how we'll feed them.

CHARLES: So maybe, someday, black soldier fly factories will dot the landscape. Courtright is talking to some big companies, working on deals to build the very first one. Maybe this time, the higher-ups won't say: Maggots? Really? Dan Charles, NPR News.