Scientists see role for insects and ‘orphan crops’ in human diet

Remarkably few plant and animal species dominate global agriculture and food production. Cattle, sheep, pigs and poultry make up most of the livestock sector, while wheat, maize, rice and soya account for 60 per cent of the world’s total crop output. Fewer than 30 species account for more than 95 per cent of human food needs.

Food security experts are pressing for diversification. “We rely too much on a very small number of crops,” says Professor Toby Bruce, a plant pest expert at Keele University.

“We see four crops travelling around the world, yet as human beings we have harvested 7,000 crops,” says Sayed Azam-Ali, professor of food security at Nottingham University, who runs the Crops for the Future research centre near Kuala Lumpur, Malaysia.

His institute is one of several aiming to identify underexploited food sources — sometimes known as orphan, neglected or underutilised crops — that could be grown more widely, particularly in the developing world.

One of Prof Azam-Ali’s favourite examples is the Bambara groundnut, which is traditionally grown by female subsistence farmers in west Africa. It is a so-called “complete food”, containing a healthy combination of carbohydrate, protein and fat. The nuts are versatile; they can be eaten whole after boiling or roasting — or dried and milled to yield a flour for making dumplings, cakes and biscuits.

Although Bambara groundnut is easily cultivated in poor, arid soil, it only grows well in the tropics. Research by Prof Azam-Ali and colleagues showed that this is because development of the nuts depends on the amount of daylight in any given day, which should not change much over the year. However, cross-breeding is now producing Bambara varieties that will do well in places further from the equator that have significant seasonal changes in the length of night and day, such as the Mediterranean.

The UN Food and Agriculture Organisation is promoting the rediscovery of crops that have been forgotten over the last century, in collaboration with the African Orphan Crops Consortium. Examples include the African yam bean, desert date, prickly pear cactus, baobab tree, teff (a grain native to Ethiopia and Eritrea) and ber (a stocky tree with a vitamin-rich berry).

The collaboration aims to enhance Africa’s food security, with “African scientists using some of the best tools and equipment available anywhere in the world to make safe, nutritious and affordable foods available on a sustainable basis,” says Tony Simons, director-general of the World Agroforestry Centre, Nairobi. “This information will allow breeders to use the same strategies and technologies as those for western crops, such as maize, to make rapid improvements in African crops.”

When talk turns to diversifying from livestock to new sources of food from animals, insects usually top the list of alternatives, followed by lab-grown meat. In the past six months two UK research teams, one at Edinburgh University and Scotland’s Rural College, and the other at Rothamsted Research in Hertfordshire and Nottingham University, have published studies of the potential of entomophagy — the consumption of insects — to replace conventional livestock production.

In ideal conditions, insects have a smaller environmental impact than more traditional western forms of animal protein

The Scottish study found that replacing half of the meat eaten worldwide with crickets and mealworms would cut farmland use by a third, substantially reducing emissions of greenhouse gases. However, in practice, the aversion of many western consumers to eating insects — and the infrastructure investment that would be required — mean that this will not happen on such a large scale.

The researchers say, though, that even a relatively small increase in entomophagy, for example by using insects as ingredients in some pre-packaged foods, would bring environmental benefits. By contrast, they found that lab-grown meat was no more sustainable in environmental terms than poultry production.

The Rothamsted/Nottingham study also found that “insects present a huge nutritional opportunity as an increasing global population seeks sustainable sources of food and feed”, but large-scale entomophagy faces cultural, social and economic hurdles, the researchers say.

“In ideal conditions, insects have a smaller environmental impact than more traditional western forms of animal protein,” says Darja Dobermann, study leader. “Less known is how to scale up insect production while maintaining these environmental benefits.”

The review found that more than 2,000 insect species are food sources, particularly in Asia and Africa. In parts of central Africa as much as half of dietary protein has historically come from insects; their market value is often higher than other sources of animal protein. In order of popularity, species for consumption include: beetles; caterpillars; bees, wasps and ants; grasshoppers, locusts and crickets; cicadas, leafhoppers, planthoppers, scale insects and bugs; termites; dragonflies, and flies. They are eaten raw, fried, boiled, roasted or dried and ground into meal.

There may be more scope for breeding insects for animal feed, including fishmeal in aquaculture, than for direct human consumption. For example, nextProtein, an agritech start-up based in Paris, rears larvae from the black soldier fly on fruit and vegetable waste from the food industry. These grubs are turned into components for aquaculture, livestock feed, pet food and agricultural fertiliser.