Common house flies (Musca domestica) may be a cheap and sustainable source of feed for farm animals, according to a scientist and an entrepreneur.
The flies, whose larvae can be bred, nurtured and ground into granules, provide roughly the same amount of edible protein as fish meal and other widely used protein sources, said entrepreneur Jason Drew.
Drew's book, The Story of the Fly and How it Could Save the World, launched in London, United Kingdom, last week, argues that the insect's larvae should be farmed commercially to provide protein for farmed fish and animals to feed the world's growing population.
Commercially bred flies can live on slaughterhouse or distillery waste, rather than on foods that could be processed and sold to humans, which also makes them environmentally sound, he said.
Drew and his brother David are breeding M. domestica to use in fish farms in their Cape Town business, AgriProtein.
Jason Drew told SciDev.Net that AgriProtein feeds its breeding stock waste human food, while the larvae produced consume slaughterhouse blood. It has taken five years to develop the larvae farming process. Around one million flies are kept in a cage of about 100 cubic metres producing about 1,000 eggs each.
The larvae are hatched and harvested within 17 days, which is how long they live before they turn into flies. They are then dried, flaked and sold as meal. Last month, the company produced 100 tonnes of wet larvae and 24.5 tonnes of feed, Drew told SciDev.Net.
AgriProtein is one of the first companies to produce high quantities of fly meal for commercial use, said Paul Vantomme, senior forestry officer for the UN Food and Agriculture Organization, in Rome.
Vantomme added that using flies as animal feeds will be "a major benefit to developing countries".
"Insect raising or gathering can be done without major cash [investments]," he told SciDev.Net. "You don't need land."
The challenges, he added, include maintaining sanitary conditions, monitoring quality, and maximising larvae production.
Drew said the company plans to design an automated process for mass production. It then plans to release technology for breeding small amounts of larvae for animal feed to help small-scale farmers in South Africa, and beyond, to develop their own livestock feed farms.
Meanwhile, a US-based company, Enviroflight, is developing black soldier fly (Hermetia illucens) larvae to add to fish meal for distribution to developing countries, according to Glen Courtright, chief executive officer of the company.
The larvae consume dry distillery grain solubles (DDGS) — a waste product from brewing and ethanol production — leaving a byproduct that can also be sold on as livestock feed.
Enviroflight is in negotiations with a global charity to use the technology to help develop fish farms in South America, Courtright said.
Similar research is ongoing in Thailand, too, but Yupa Hanboonsong, an associate professor in entomology at Khon Kaen University in Thailand, said that not all countries can use the same insects for feed.
For example, in Thailand "you cannot use crickets because people eat them," and it is, therefore, too expensive to use for livestock feed, Hanboonsong said. Also, some insects are parasites on other commercially valuable animals, such as the silk worm, so they should not be bred, he said.
"If we are not careful about which are the right species to breed, it may destroy our silk industry," Hanboonsong told SciDev.Net.
Developing an alternative source of protein would directly benefit the poor, said Monica Ayieko, associate professor at Bondo University College, in Kenya, who is researching breeding crickets.
"The problem we have in Kenya, as in many other parts of Africa, is that animal feed is competing with human feed," Ayieko told SciDev.Net.
For example, she said, near Lake Victoria, the poorest people depend on a small fish that used to be cheaper to purchase than most other foods. Now that this fish is being used as feed for fish farms and for pet stores, the price has gone up so only well-off consumers can buy it, she added.
"The challenge will be mass rearing insects," she said.