Environmental benefits of insects as food
Edible insects are an environmentally attractive alternative to conventional livestock because they require less feed and water; they produce lower levels of greenhouse gases and can be raised in small spaces. Worldwide, livestock production is considered among the most ecologically harmful of all anthropogenic activities with massive direct and indirect contributions to global warming (72-78% of total agricultural emissions). This is due to low feed-conversion efficiencies, enteric fermentation in ruminants, and manure-related emissions (van Huis, 2020).
Greenhouse gas production (global warming potential), energy use and land use due to the production of 1 kg of protein from mealworms, milk, pork, chicken and beef.
Figure 1. The global warming potential, energy use, and land use are compared for mealworms are compared with milk, pork, chicken, and beef. Mealworms were found to have significantly lower greenhouse gas emissions along with a smaller production footprint (van Huis and Tomberlin, 2017)
Insects are physiologically and biologically different from other animal species. Insect metabolism does not require a constant body temperature like the vertebrate species traditionally used for human consumption. Being cold blooded insects have a high feed conversion efﬁciency. This means more efficient use of resources such as feed and water and emit fewer greenhouse gases by a factor of 100.
Figure 2. Gut morphology of the House cricket Acheta domesticus L (Drawing by Stijn Schreven) (Eilenberg and van Loon, 2018)
Feed-to-meat conversion rates (how much feed is needed to produce a 1 kg increase in weight) vary widely depending on the class of the animal and the production practices used, but nonetheless insects are extremely efﬁcient. On average, insects can convert 2 kg of feed into 1 kg of insect mass, whereas cattle require 8 kg of feed to produce 1 kg of body weight gain.
Insects use significantly less water than conventional livestock. Mealworms, for example, are more drought-resistant than cattle. Insect farming is less land-dependent than conventional livestock farming. In addition, the final mass of the insects is completely usable, guaranteeing yields close to 100%.
Insect rearing holds the potential to reduce some environmental problems. In most cases the advantages are related to the fact that the insects are more efficient at converting feed into protein than other animals (Halloran et al., 2018).
Eilenberg, J., van Loon, J.J.A., 2018. Insects: Key Biological Features, in: Halloran, A., Flore, R., Vantomme, P., Roos, N. (Eds.), Edible Insects in Sustainable Food Systems. Springer International Publishing, Cham, pp. 3–15. https://doi.org/10.1007/978-3-319-74011-9_1
Halloran, A., Hansen, H.H., Jensen, L.S., Bruun, S., 2018. Comparing Environmental Impacts from Insects for Feed and Food as an Alternative to Animal Production, in: Halloran, A., Flore, R., Vantomme, P., Roos, N. (Eds.), Edible Insects in Sustainable Food Systems. Springer International Publishing, Cham, pp. 163–180. https://doi.org/10.1007/978-3-319-74011-9_11
van Huis, A., 2020. Insects as food and feed, a new emerging agricultural sector: a review. J. Insects Food Feed 6, 27–44. https://doi.org/10.3920/JIFF2019.0017
van Huis, A., Tomberlin, J.K. (Eds.), 2017. Insects as food and feed: from production to consumption. Wageningen Academic Publishers, The Netherlands. https://doi.org/10.3920/978-90-8686-849-0