In one year, a single acre of black soldier fly larvae can produce more protein than 3,000 acres of cattle or 130 acres of soybeans. Such yields, combined with the need to find cheap, reliable protein for a global population projected to jump 30 per cent, to 9.8 billion, by 2050, present a big oppor­tunity for the black soldier fly. The United Nations, which already warns that animal-rich diets cannot stretch that far long term, is encouraging governments and businesses to turn to insects to fulfil the planet’s protein needs.

People who’ve seen what black soldier fly larvae can do often speak of them in evangelical tones. Jeff Tomberlin, a professor of entomology at Texas A&M University, says the bug industry could “save lives, stabilise economies, create jobs and protect the environment”.

“There’s no reason why we shouldn’t be doing this at some scale throughout the world,” he says.

So why aren’t we?

When the LED lights are flipped on in the fly-breeding room at Evo Conversion Systems, the whirr of thousands of tiny wings fills the air as flies careen about their screened-in enclosures in search of a mate. Evo, which was founded by Tomberlin, shares a wall with Symton. The companies are separate but symbiotic: Evo hatches fly larvae and sells them to Symton, which fattens them up on a proprietary grain blend that ensures optimal nutrition for the animals that eventually will consume them.

The adult flies resemble small black wasps, minus a stinger, and are generally harmless to humans. After they’ve mated, the females deposit clutches of several hundred eggs into small pieces of corrugated cardboard. Evo employees collect the cardboard and deposit them into glass Mason jars to incubate. Several days later, a brood of maggots – each no bigger than a speck of pepper – hatches.

Entomologists have known of the soldier fly’s promise for decades. Researchers proposed using them to convert manure into protein as early as the 1970s. But raising them on anything approaching a commer­­cial scale seemed like a dead end: no one knew how to get captive flies to reliably mate and deposit eggs.

That changed in 2002, with the publication of a paper by Tomberlin, his adviser, D. Craig Sheppard, and others, which described a system for raising the insects in captivity. The key, they found, was finding the precise mixture of temperature, humidity and, especially, lighting to stimulate the flies to breed.

Before the paper, “people thought we were crazy” for trying to grow soldier flies, Tomberlin says. The fact that the technology to properly cultivate fly colonies didn’t even exist 20 years ago underscores how new the industry is, he adds.

A black soldier fly larva can consume twice its weight in food each day. On its 14-day journey from hatchling to pupa, a single larva will grow nearly an inch long and increase its weight by a factor of 10,000. That’s akin to an eight-pound baby swelling to the size of a 40-tonne humpback whale. They binge eat to store up nutrients for their two-week life span as adults, when they typically don’t eat anything at all.

The larvae at Evo feast on spent grains from a handful of Texas distilleries and breweries, as much as 15 tonnes of it each month. Nathan Barkman, of Rio Brazos Distillery, says Evo eliminates close to half of his company’s weekly output of waste. It’s hot, sopping wet, highly acidic and sticky – “like lava”, he says – making it difficult to dispose of. Local sanitation companies won’t take it. Pig farmers sometimes will, but the closest farms are miles outside town, and nobody wants to be driving molten grain mash that far.

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The flies, however, love it. “They’re generalists,” Tomberlin says, and eat just about anything. Pig manure? Check. Human waste? Check. Food scraps? Check. The only organic materials they haven’t had luck with are bones, hair and pineapple rinds, he says.

Their ability to rapidly devour waste has inspired a number of commercial applications. A pilot programme at Louisiana State University deploys a small colony of soldier flies to consume the food its students toss out at one dining hall. The entomologist overseeing the project hopes it will be expanded to eliminate all campus food waste by the end of the year. In China, giant facilities owned by a company called JM Green process at least 50 tonnes of food waste a day with the help of black soldier flies.

Using larvae to eliminate food waste on this scale could be an ecological game-changer. A 2011 UN report detailed how rotting food emits millions of tonnes of carbon dioxide into the atmosphere, accounting for about 7 per cent of the world’s greenhouse gas emissions. But when maggots consume food waste, they take all that carbon with them.

Soldier flies are “where carbon goes to die”, Tomberlin says. “It goes into this system and comes out the other end as all these beneficial ingredients.”

Such as food for animals.

In Symton’s entryway sits a grumpy chameleon named Eugene, who’s prone to hissing at visitors who get too close. There’s also a sweet-natured leopard gecko that spends most of her day snoozing under a rock. Hanging from the ceiling is a potted Asian pitcher plant, its long fleshy cups dangling over the pot’s edges, maws agape.

The chameleon, gecko and pitcher plant have one thing in common: they eat soldier flies.

One of the first commercial applications for soldier fly larvae was as live feed for pet reptiles. The reptile market took off in the 90s, says David Fluker, a second-generation cricket farmer and the owner of Fluker Farms in Louisiana, after the 1993 film Jurassic Parksparked interest in dino­saurs and their most attainable approximations.

“Reptiles were reasonably popular, but they just went off after that,” he says.

Crickets and mealworms – farmed for decades in the American southeast, first as bait for fishers – had long been the twin pillars of the lizard-food industry. The problem, though, is they cannot meet reptiles’ calcium needs. That means pet owners must dust the live feed with the mineral to guard against calcium deficiency, which can cause tremors, seizures and even death.

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The soldier fly solves that problem. Tomberlin’s adviser, Sheppard, discovered they are extremely high in calcium – 50 times more per gram than mealworms and crickets. Within a few years, by 2006, he secured a trademark to use soldier fly larvae as feed for geckos, bearded dragons and other reptiles. Soon after, other more established pet food companies entered the market with their own soldier fly brands.

Symton is one of the more recent entrants into that market. The Texas company occupies several thousand feet of commercial warehouse space and has about a dozen employees. It’s already profitable and growing fast: larvae production has doubled in the past six months, up to 2 million a week.

Most of the magic happens in a single room filled with racks of open plastic tubs. Each container holds thousands of grubs in various stages of development, happily munching their way through piles of specially formulated grain mash.

Because soldier fly cultivation is so new, there was much trial and error to get the company to where it is today, Taranow says. Researchers had to calculate the right combination of food and moisture (cricket production, by contrast, is so well-established that you can purchase commercial cricket chow in 20kg bags). They had to lock down the proper grub-to-feed ratio, as well as the precise temperature, lighting and humidity needed to ensure larvae reached the desired size. If any variable is out of whack, the entire colony can crash.

Another challenge for soldier fly farmers is that larvae are surprisingly mischievous. A wet grub can scale any surface, from wood to glass, so growers have to maintain specific humidity levels to prevent them from getting damp, escaping their confines and generally running amok. A group of dry larvae left alone in an enclosure without food will congregate in a corner, piling up World War Z-style until they’re tall enough to allow their compatriots to escape. Symton solved this problem, in part, by piling wet mash in the centre of their bins with a moat of dry material along the edges to prevent escape.

After they reach the desired size, the larvae are sifted out, weighed and poured into plastic containers and then shipped all over the country. One by-product of the process is frass – the scientific term for bug excrement. Symton produces scads of the stuff, which it piles up outside the facility and donates to local landscapers for use as compost.

An acre of land used to raise soldier fly colonies can produce more than 60,000kg of protein per year, according to various peer-reviewed estimates. That’s several orders of magnitude greater than the per-acre protein yield of cattle (about 18kg), soybeans (430kg) or chickens (816kg).

“Black soldier fly larvae can make thousand-folds more protein than other terrestrial animals or plants,” says Liz Koutsos, chief executive of Kentucky-based EnviroFlight, which raises soldier fly larvae used in protein meal for commercial fish and poultry operations. The yields are so high because soldier fly colonies can be stacked vertically, five to 10 per floor, in a way that isn’t possible with cattle or field crops. The fast-growing larvae can be harvested dozens of times per year.

EnviroFlight, like Evo, feeds its larvae by-products of the distilling industry. When the grubs reach full size, they’re harvested, dried in industrial ovens and processed into a protein-rich meal and oil. The technology is moving so quickly, however, that regulators are having difficulty keeping up.

Black soldier fly meal only won approval as fish and poultry feed in 2018. Koutsos says EnviroFlight and companies such as Enterra, in Canada, and Protix, in the European Union, are working to win regulatory approval to use the meal in food for other animals, including swine and even cats and dogs.

The idea is to take pressure off traditional sources of protein meal, such as fish. About one-quarter of the harvest from marine fisheries is turned into food for farmed animals, including fish, pigs and poultry. More than 90 per cent of those fisheries are either fully exploited or over­fished, meaning that as the world’s population grows, there will be more demand for alternative protein sources.

“There’s no question that [soldier fly] meal is much more expensive right now than fishmeal,” Koutsos says. But fishmeal is becoming more expensive, and soldier fly technology is becoming cheaper. The goal, she says, is “to be at or below fishmeal [prices] in five years.”

“Twenty years ago, I would have laughed” at the idea of feeding the world with bugs, says Fluker, the cricket farmer. He recently expanded into soldier fly production and discovered the grubs will eat the frass produced by his millions of crickets. He says he views insect farming as “a vital link to sustaining the world’s feed needs”.

The economics are promising enough that big agri­cultural companies are getting into the insect protein market. Cargill, the Minnesota-based agriculture giant, recently announced a partnership with the French biotech firm InnovaFeed to produce fish feed made from black soldier fly larvae.

“Insect protein feed can be a solution and a renewable source of protein to feed fish and ultimately feed the world,” says Maye Walraven, InnovaFeed’s head of business development, in a video announcing the partnership.

The UN agrees: it forecast in a 2013 report that insect farming would have to play a key role – both as animal feed and to feed people – if the world is going to eat sustainably in coming decades.

Back at Symton, Taranow pops a couple of oven-dried soldier fly larvae into her mouth. “Honestly, they taste like Fritos,” she says.

They have a pleasant, neutral, nutty flavour. Slather them in powdered ranch or barbecue seasoning and it’s easy to imagine bags of them flying off the shelves in convenience stores.

The dried larvae also have an advantage over other insect edibles in that they don’t really look like bugs. They have few identifiable buggy characteristics – no legs to get stuck in your teeth, no eyes to stare at you. It would be easy to mistake them for some sort of exotic grain.

Close to 2 billion people worldwide already include insects in their diets, according to the 2013 UN report. Insect-based snacks are commonly seen in open-air mar­kets in Thailand, China and elsewhere.

The practice hasn’t caught on in Europe or the United States, in part, because of long-standing cultural attitudes toward insects. This is somewhat puzzling, considering many Westerners happily consume foods such as crab and lobster, which are really just giant sea bugs.

“I absolutely think there will be applications [for the soldier fly] in the human food market,” says Koutsos. “The challenge is getting over the cringe factor.”

One potential path to human consumption is via insect-based protein powders, which can be mixed with other foods, thus lessening the ick factor. Several companies are already doing this with crickets.

“There’s been a lot of effort put into cricket flour or mealworms for protein ingredients for everything from pasta to cookies to chips,” Tomberlin says.

He expects soldier fly protein to follow a similar path. “When you walk in these facilities in 10 years, we’ll look back at this era and say we were just getting started.”

Will Western consumers ever embrace insect-based protein? Twenty years ago, as Fluker says, the idea would have been laughable. But today, in the era of the vegetarian Whopper, the door is open.

Text: The Washington Post