Environmental impacts
Land use
Overall, the operation of insect farms, including large-scale farms, requires comparatively smaller infrastructure and facilities than for other animal-rearing operations. Growing feed (e.g., grains and carrots) account for the largest portion of land use in insect production.
Insects are generally reared in closed environments using vertical farming solutions or modern technologies (e.g., bioreactors).[1] Recent studies indicate that the land use impact of insect production is 0.36–3.6 m² per 1 kg of biomass as opposed to 23.1 m² in the case of beef, 4.64 m² for chicken and 1.48 m² for feed formulations.[2]
Water use
Together with land use and antibiotics, water usage is one of the few main agricultural inputs that farming insects requires. To date most studies evaluating the water footprint of insect production have focussed on insects grown on conventional diets. Their findings indicate that the lowest insect water footprint is in the range of 0.4-0.8 m3 per 1 kg of insects biomass, which is higher than conventional protein sources.[3]
Greenhouse gas (GHG) emissions
GHG emission levels in insect production are largely influenced by the substrates used to feed the animals. These can be further reduced by feeding insects on organic waste, for example.[4]
The carbon footprint of insect farming has been estimated to be on average in the range of 0.3 – 3.0 kg CO2 equivalents per 1 kg of insect biomass, which is lower than conventional alternatives, and broadly equivalent to feed formulations.[5]
Waste
The main by-product of insect farming is frass (insect excrement), which can be used as a fertiliser, for soil improvement and crop protection.[6] Uneaten feeding substrates are also a by-product of insect production.
Insects have significant potential in terms of circular economy. Most species can be fed on organic waste (e.g., manure, kitchen waste etc.), thereby valorising by-products that otherwise would not be exploited, and used for human and/or animal consumption.[7]
Also, insect feed conversion ratios (FCRs) – that is the amount of feed required to produce 1 kg of edible meat – are better than that of other food-producing animals. Depending on the diets they are fed, the FCR of black soldier fly may range from 1.4 up to 2.6, while in the case of yellow mealworm from 3.8 up to 6.1. Consequently, such species perform better than beef (FCR = 8.8), whereas only the black soldier fly compares to poultrymeat (FCR= 2.3).[8]
[1] Jiang G, Ameer K, Kim H, Lee EJ, Ramachandraiah K, Hong GP, Strategies for Sustainable Substitution of Livestock Meat, Foods, 2020, 9(9), 1227.
[2] Smetana S, Bhatia A, Batta U, Mourim N, Tonda A, ‘Environmental impact potential of insect production chains for food and feed in Europe’, Animal Frontiers, Volume 13, Issue 4, 2023, p. 112–120, https://doi.org/10.1093/af/vfad033.
[3] Smetana S, et al., 2023.
[4] Smetana S, ‘Circularity and environmental impact of edible insects’, J Insects Food Feed, 2023, 9(9), p. 1111-1114.
[5] Smetana S, et al., 2023.
[6] Hénault-Ethier L, Reid B., Hotte N., Paris N., Quinche M., Lachance C, et al., Growth Trials on Vegetables, Herbs, and Flowers Using Mealworm Frass, Chicken Manure, and Municipal Compost, ACS Agricultural Science & Technology 2023, https://doi.org/10.1021/acsagscitech.2c00217 and Wantulla JJ A, van Loon A and Dicke M, Soil amendment with insect exuviae causes species-specific changes in the rhizosphere bacterial community of cabbage plants, Applied Soil Ecology 2023 Vol. 188, p. 104854, https://doi.org/10.1016/j.apsoil.2023.104854.
[7] Wang Y and Shelomi M, Review of Black Soldier Fly (Hermetia illucens) as Animal Feed and Human Food, Foods 2017, 6, 91.
[8] Oonincx DGAB, van Broekhoven S, van Huis A, van Loon JJA, Feed Conversion, Survival and Development, and Composition of Four Insect Species on Diets Composed of Food By-Products, PLoS One, 2015 Dec 23;10(12):e0144601.