Feeding the World with Edible Insects

Goggy Davidowitz, Department of Entomology, University of Arizona, USA

I was somewhat apprehensive about knocking on her door. “Worst comes to worst,” I thought, “she would say no.” I was scheduled to give a talk on edible insects and wanted to ask our head of restaurant Dunia if it would be possible to buy cricket cookies and mealworm chips to hand out. As I feared, Dunia’s immediate response was, “No”… followed by: “We will buy the insects and make something ourselves!”

And so it was. For a December 2022 Thursday Colloquium, I gave a talk entitled“ Feeding the world with edible insects”, followed by insect-based appetizers at the cocktail hour before dinner. A problem in the kitchen almost derailed the whole plan, but Dunia did her magic and whipped up three dishes as I was giving my talk: chocolate-covered mealworms, cricket pesto, and grasshopper crunchies. By dinner time, none were left. The appetizers were particularly popular with the Wiko kids.

The edible insect industry is growing at a remarkable pace. Since 2013, an estimated 1.1 billion Euro has been invested, mostly in the EU, and is expected to reach about 9.1 billion Euro by 2030. As of 2022, there were over three hundred registered companies worldwide growing insects for food and feed. Fifty-nine of these are based in twenty countries in Europe, of which eight are in Germany.

Why the interest in edible insects? The initial motivation is the need to feed over ten billion people by 2050. Using current agricultural practices, that is simply not possible. Alternative solutions for protein production are being sought, with insect protein as sustainable foodstuffs gaining momentum.

There are now scores of studies comparing the nutritional value of insects with vertebrate livestock. Per calorie serving, insects contain more protein and less fat than cows or fish and contain much higher quantities of minerals such as calcium, potassium, iron, and zinc than do chickens. Nearly all the fats in insects are unsaturated, healthier than the saturated fats in beef or chicken skin. The outer skeleton of the insect, which is not digestible, is fiber, also good for you.

Insects can be grown more sustainably than vertebrate livestock, by orders of magnitude. To produce 1 kg of protein from cows, about 15,400 liters of water, including the water needed to grow their food, are needed. This is equivalent to one and a half tanker trucks. In comparison, to produce one kilogram of protein from insects, you need only about five liters of water.

There is also a very big difference in the amount of feed needed to produce protein. From 10 kg of feed, we can produce about 1 kg of protein from cows, versus 9 kg of protein from insects. Thus, the conversion efficiency of insects is nine times higher than that of cows. Why is that? Cows, like all mammals, are endotherms, that is: warm-blooded. They need to burn off much of their food to maintain a constant body temperature. In contrast, insects’ body temperatures fluctuate with the environment. As such, they can put much more of what they eat into growth.

Insects need only 7% of the land required for cattle to produce the same amount of protein. Moreover, cattle can be raised only in a monolayer, on the ground. In contrast, insects are very amenable to vertical farming, with some facilities stacking the growth bins two stories tall. This reduces the insects’ “footprint” even further.

What do I do with edible insects at my home institution, the University of Arizona? I do not grow insects for food. Rather, we develop technologies for the future. We focus mostly on how to use food waste (mostly fruits and vegetables) to grow insects. Each year, about one-third of all the food that is produced globally ends up in the landfill. That is about 1.3 billion tons that are worth over 913 billion Euro wasted. This food waste generates nearly ten percent of all greenhouse gases, a significant contributor to global warming.

We are working to mitigate this situation, using insects. There are two types of wasted food. A significant portion is rotting and cannot be eaten. A small portion of this rotting waste is captured before it gets to the landfill and is turned into compost that is then used as fertilizer for plants. We envision something different. We compost rotting food, but then modify it in a way to make it attractive to insects that eat decaying organic material. We then use these insects in aquaponic systems to feed fish. Aquaponics combines aquaculture (fish farming) and hydroponics (growing plants on nutrient-rich water instead of soil). The general idea of aquaponics is this: you feed the fish, and their excreta is then diverted to a biofilter that contains bacteria. These bacteria turn the ammonia into nitrates and nitrites, both major components of plant fertilizer. This is then diverted to the plants. Instead of using commercial fish food, which is 80% of the cost of farming fish, we feed the fish insects. We are finding that both the fish and the plants grow much better when the fish are fed insects.

Another type of food waste is made up of fruits and vegetables that are still fresh and ready to eat but that haven’t made it into the supply chain, largely because they are grown in excess. This high-quality surplus can be used to feed insects that people can eat. A significant constraint is that the fruits and vegetables have to be processed before they rot. To accomplish this, we have developed a drying tower that uses solar radiation to dry the fruits and vegetables. The tower is about 4 x 4 x 8 meters, nearly as high as the main Wiko building. In this tower, surplus fruits and vegetables dry faster than in a commercial dehydrator; in the process, the heat kills the bacteria that are on the plants. Moreover, fresh fruits and vegetables are about 95% water. We recapture the evaporated water from within the tower such that for every ton of waste we process, we get back nearly a cubic meter of water. This reclaimed water is drinkable or can be used for irrigation.

At the University of Arizona, we are also working on another invention: the current paradigm in agriculture is that plants need to be protected, and insects need to be controlled. In my lab, we turn this paradigm around: let insects eat plants, and then harvest the insects. Grasshoppers, in particular, are major agricultural pests: the most severe are locusts, which can swarm by the hundreds of millions. We are developing an AI- and GPS-controlled grasshopper harvester, a semiautonomous robot that captures grasshoppers as they jump. The harvester can be used for pest control or to collect grasshoppers for food. My ultimate goal is to deploy fleets of these in locust breeding grounds to mitigate locust swarms. Will this solve the locust problem? Of course not. But if the harvesters can prevent one village from completely losing its crops, it is worth a try.

In the weeks after giving my lecture, I had many discussions with Wiko Fellows and partners about insects and how to get people to eat them. Even though I came to Wiko to work on a project on insect physiology that had nothing to do with edible insects, my discussions with Fellows at meals gave me an idea. One of the great things about Wiko is the library. The librarians can find almost anything for you. There are now over a dozen cookbooks devoted exclusively to insect recipes. Enlisting invaluable help from Stefan Gellner from the library, I assembled as many of these cookbooks as I could. The question: how do cookbooks present insects? Do they make a statement with whole insects featured prominently in the dish, or do they do it by stealth, grinding the insect into powder so it is just one more unrecognizable ingredient out of many? As every Wiko Fellow can relate to, this is one more project that wasn’t finished at the end of my year in Berlin – but I have every intention to finish up.