Insects have been touted as a food of the future, particularly because of their sustainability benefits.
An excellent source of protein, their production requires far fewer resources than traditional agriculture. Give your mealworm farm about 2 kilograms (4.4 pounds) of feed and you’ll get one kilogram of edible protein; with beef, it would take 10 times as much space and produce 18 times as much greenhouse gas.
In a new opinion piece, scientists have proposed that switching to a diet that incorporates insects could also have additional positive effects on the way we farm.
In the article, the authors discuss the use of waste created by insect production for food and feed, and the benefits the waste could have on growing sustainable crops.
Insect farm byproducts could potentially provide farmers with an organic soil additive that promotes plant growth and impacts the soil microbiome in a way that can promote plant health.
“A new organic soil amendment is emerging from the production of a new source of animal protein, namely the production of insects such as the yellow mealworm (Tenebrio molitor), small mealworm (Alphitobius diaperinus), house cricket (Acheta domesticus), soldier fly (Hermetia illucens), or house fly (Musca domestica) for food and feed,” the authors of the paper state.
The production of insects for food and feed generally results in two by-products: exuviae and insect excreta. Exuviae are the exoskeletons left behind after insects molt, and excreta are essentially insect poop and uneaten insect food; both byproducts could become potential alternatives to conventional fertilizers and pesticides.
“An important component of insect exuviae is chitin, a high molecular weight amino sugar polysaccharide that is also present in the fungal cell walls and exoskeleton of many crustaceans. Soil amendments containing chitin have been shown to promote plant growth,” the authors note.
“However, there is a set of bacteria that can metabolize chitin, and these microbes help plants be more resistant to diseases and pests,” says Marcel Dicke, a plant biologist at Wageningen University in the Netherlands and co-author of the study. paper.
“When exuviae are added to the soil, populations of these beneficial bacteria increase.”
In addition, adding insect excreta to the soil can promote plant growth because insect excreta are rich in nitrogen, a nutrient that is crucial for plant growth but can be scarce in most soils. Nitrogen is often added to soils in the form of synthetic fertilizer.
“Similarly, adding insect excrement to soil has been shown to provide nitrogen and other nutrients to plants that increase their biomass and nutritional content. Chitin and insect excreta amendments impact the composition of the soil microbiome, which may be an important factor in promoting plant growth and health,” the paper’s authors state.
The researchers also mention the potential of exuviae as a means of pest control. Beneficial soil bacteria that metabolize chitin from exuviae may not only stimulate plant growth, but also cause changes in plant physiology, attracting mutualistic insects.