The best way to feed the 9 billion people expected to be alive by 2050 could be to rear billions of common houseflies on a diet of human feces and abattoir blood and grind them up to use as animal feed, a UN report published on Monday suggests. Doing so would reduce the pressure on the Earth’s forests and seas as food sources.
The case for houseflies — or other insects like crickets, beetles, bees, wasps, caterpillars, grasshoppers, termites and ants — becoming a major industrial food source is being taken seriously by governments, the report says, because they grow exceptionally fast and thrive on the waste of many industrial processes.
The authors envisage fully automated insect works being set up close to breweries or food factories that produce high volumes of farm waste. Each could breed hundreds of tonnes of insects a year that would be fed to other animals.
“The prospect of farms processing insects for feed might soon become a global reality due to a growing demand for sustainable feed sources,” say the authors, who have been working with the UN Food and Agriculture Organization (FAO) on the potential for insects improving human food security.
“The bioconversion process takes low-cost waste materials and generates a valuable commodity. Depending on the species, a single female fly can lay up to 1,000 eggs over a seven-day period, which then hatch into larvae. Potential big users would need vast quantities of the product — some pet food businesses alone could use over 1,000 tonnes per month,” the report adds.
Termites, mealybugs, dung beetles, stink bugs, leaf cutter ants, paper wasps and even some species of mosquitoes are all relished by someone, the study says.
Eighty grasshopper species are regularly eaten; iin Ghana during the spring rains, winged termites are collected and fried or made into bread. In South Africa, they are eaten with a maize porridge. Chocolate-coated bees are popular in Nigeria, certain caterpillars are favored in Zimbabwe and rice cooked with crunchy wasps was a favorite meal of the late emperor Hirohito in Japan.
The crunch factor for governments and food producers may be the lower costs. Cattle and poultry are poor at converting food to body weight, but crickets, says the report, need just 2kg of feed for every 1kg of weight gained.