The role of edible insects to mitigate challenges for sustainability

4.1 Environmental impact

It is estimated that around 80% of the GHG emissions caused by the agricultural sector comes from livestock production on a broad sense, which includes the emissions originating in land used for foraging, from the energy used to grow cereals for animal feed, and also from the transportation of feed and meat to the processing companies and to the sales players (McMichael et al. 2007). In view of this, alternative approaches rely on insect-based protein supply because of the minored environmental impact of insect breeding. This is so because insects possess single physiological characteristics and biological structures, which allow high efficiency in the conversion of protein into animal protein and also feed energy into food energy, when compared to traditional livestock species. Because insects are poikilothermic (i.e., their internal temperature varies considerably), their metabolism does not need to supply energy to maintain their body temperature, contrarily to homeothermic animals (hot-blooded). This is the reason why the feed conversion ratio (FCR) sometimes designated by feed conversion efficiency (FCE) is considerably higher. FCRs vary considerably depending on the class of animal and the particular conditions of each meat production. Nevertheless, estimations based on the statistics for the United States indicate that the FCRs for traditional meat production systems are 10 for beef, 5 for pork, and 2.5 for chicken, whereas the FCRs for edible insects are comparatively lower, around 1. Figure 1 shows, as an example, the comparative input/output balance for beef and cricket production, showing that to obtain 1 kg of beef the consumption is 3,000 times more water, 12.5 times more feed, and the necessary areas for husbandry are much higher, when compared with crickets (Smil 2002; Ramos-Elorduy 2008; Nelson et al. 2009; Huis 2013; Huis et al. 2013; Halloran et al. 2016).

Figure 1

Comparative input/output balance in beef and cricket production.

Rearing edible insects create lower impacts on the environment when compared to producing other animal proteins. The environmental impacts of insect production, considering feed conversion, land use, and water spending, are incredibly lower than for other types of animals, specifically poultry, pig, and cattle, as indicated in the graphs in Figure 2. The graphs compare the amounts of feed, land, and water required to produce an equivalent amount of insect, chicken, pig, and beef. Insects require the least, followed by chicken, pig, and cow for feed, land, and water usage. Comparatively, cows require over five times more feed, land, and water than insects. It is also taken into consideration the fraction of edible mass, which varies significantly amid conventional livestock and insects. Calculations for protein efficiency indicate that beef, pork, and poultry have values of 190, 150, and 200 g protein/kg of edible mass, respectively, whereas in the case of cricket the values are 154 and 205 g/kg, respectively, for nymphs and adults (Finke 2002; Huis 2013).

Figure 2

Some measures of environmental impact of animal production, according to the species.

The use of insects as food and animal feed appears as a very interesting choice from the perspective of environmental impact in comparison to the usual and more conventional sources of animal protein. The quantification of this impact is currently made through life cycle assessment (LCA) calculations. Halloran et al. (2016) suggested a versatile reference framework for LCA applications in systems for insect production, based on the selection of standardized settings.

4.2 Economic and social impact of the market of edible insects

Over the 5-year period from 2018 to 2023, the edible insect market is expected to grow from about $400 million in 2018 to almost $1.2 billion in 2023 (Figure 3), corresponding to an increase of about 25% per year. Further ahead predictions indicate that this market might be worth around $8 billion by 2030. Although Asia-Pacific and Latin America account for over 50% of the market, it is expected that strongest increases might happen in North America and Europe (Goldstein 2018; Bombe 2019).

Figure 3

Expected growth of edible insects’ market value according to the different regions.

The market of edible insects in Asia Pacific area is expected to exceed $270 million by 2024. In Cambodia, insect farming is becoming a key factor to fight against rural poverty. Family farmers and poor families are upscaling cricket production, thus improving their livelihoods. One can with 150–200 g of fried crickets is worth between 0.40 and 0.70 €.

Thailand, where many people enjoy eating a wide variety of insects, leads the world production of insects aimed at human consumption. In recent years, the annual insect production is 7,500 tons, originating mostly from small family enterprises spread all over the country, thus generating a multimillion-dollar industry. The insect production is actually saving poor Thai farmers, generating income and providing a means of livelihood to families. There are over 20,000 listed farms in Thailand, most of them small-scale household operations. Many of them breed crickets, which grow very fast, take up little space and with minimal work (Hanboonsong et al. 2013; Takoradee 2019). On the contrary, Mueller (2019) reported recently a decreasing trend in the insect-eating traditions in Laos and Thailand, owing to the “Westernization” of their dietary habits. This is particularly intense in rural areas, because in urban areas there seems to be some revivalism of the insect-eating practices. Therefore, despite the growing global interest in using insects as human food, some issues still need to be analysed (Mueller 2019). Meyer-Rochow et al. (2008) reported that in Laos people do not have insect in high consideration, seeing them as inconvenient and carriers of disease.

Besides the food and feed markets, also other possibilities are linked with the insect production. In China, recently, cockroach farming has flourished, with some entrepreneurs becoming wealth by selling dried cockroaches for processing into cosmetics and traditional medicines.

In South Korea, the silkworm pupae are a by-product of the silk industry, but because they are edible they have been used as food since many centuries back. On the contrary, edible crickets are much more recent, being reared and consumed for only about 20 years now. Despite being more recent, cricket farming has potential to grow, because the demand for cricket flour is increasing because of its utilization as protein-rich additive in the baking industry (Meyer-Rochow et al. 2019; Cappelli et al. 2020c). As reported in 2019 by Meyer-Rochow et al. (2019), the quantity crickets produced in Korea is muffled by the production of silkworm pupae (10 tons of silkworm pupae are grown per year, from which only 20% are aimed at the market of food and feed).

In many African countries, such as Kenya, Cameron, Uganda, and Burundi, insects provide earnings for many people along the edible insect supply chain, including farmers, collectors, wholesalers, and retailers (Odongo et al. 2018; Tamesse et al. 2018; Baiano 2020). Odongo et al. (2018) studied the edible insects market in the basin of Lake Victoria (areas included in Uganda and Burundi). Their results indicated that edible insects were traded mostly on urban areas, being considered as treats. In addition, they postulate that this market has the potential to increase because of the increasing demand, because at present the demand largely surpasses the offer, which leads to an increase in the prices of insects as compared with beef, pork, or poultry (Odongo et al. 2018).

Tamesse et al. (2018) investigated the importance of certain key insects in Cameroon (honeybees, crickets, cockchafers, and termites) for local villagers. Their results have shown that most people (around 3/4) eat insects and allowed identifying the most consumed as being termites and crickets and the least as being honeybees, because of fear of their venom. Besides their use as food, people in Cameroon also use them in folk medicine, cultural rites, and indigenous traditions (Tamesse et al. 2018).

6.1 Insects as ethnic food

In some populations, insects are considered a delicacy. Insects like grasshoppers, cockroaches, larvae, among others are consumed because of their rich protein content, attractive crunchiness, and appreciated taste. Nevertheless, there are important obstacles to consumers’ acceptance of edible insects and foods with ingredients derived from insects, especially in western countries. In this way, although entomophagy is naturally recognized in some countries around the world, most especially in Africa, Asia, and South or Central America, it is also true that it is not fully accepted or understood by westerners. Disgust and neophobia were identified as chief psychological barriers averting the consumption of insects (Payne et al. 2016; Verneau et al. 2016; La Barbera et al. 2020).

Insects are consumed by over 2 billion people (Baiano 2020). More than 2,000 species of insects (2,140, as reported) are recognized as being consumed by more than 3,000 ethnic groups in up to 130 countries, concentrated mostly in sub-Saharan Africa, central and south America, or in the southeast Asia and the Pacific. The countries with the highest consumption of insects as food include: Democratic Republic of the Congo, Congo, Central African Republic, Cameroon, Uganda, Zambia, Zimbabwe, Nigeria, and South Africa. Nevertheless, there are 11 countries in Europe which are entomophagous (Ramos-Elorduy 2009; Mitsuhashi 2017; Gahukar 2020; Hwang and Choe 2020).

The most frequently consumed insects comprise crickets, caterpillars, palm weevils, and termites. About 200 types of edible insects are consumed in the south-eastern part of Asia. In India, Ayekpam et al. (2014) documented 46 insect species which are used as food among various tribes in Manipur. The Muria tribes in Madhya Pradesh state traditionally consume some species of ants and also an insect known as chin kara. According to some authors, an ancient practice of entomophagy is also present among the people of the Ao-Naga tribe, which populate the district of Mokokchung in the Indian state of Nagaland (Firake et al. 2019; Pongener et al. 2019; Johnson 2020). According to Mozhui et al. (2020), entomophagy is very common in the Nagaland, whose ethnic groups eat a variety of insect species as healthy foods after cooking or raw.

Honeypot ants, with a very prominent belly (swelling to the size of grape berries) filled with a particular nectar, are consumed raw as sweet delicacies by the aborigine peoples in Australia. The huhu beetle grub, similar to big maggot, is eaten as uncooked snack or sautéed as a singular meal in New Zealand, where it is considered a delicacy. Palm weevil larva is eaten in Nigeria, Papua New Guinea, and Malaysia. Wasp larva is eaten as a crunchy snack in some areas of Japan, cooked in sugar and soy sauce, and sometimes mixed with cooked adult wasps. Dragonfly is eaten in Indonesia, boiled or fried as a special treat. Scorpion is eaten in Vietnam, Thailand, and China, boiled or fried as a special treat. Silkworms, known as Nhon Mhai, are the preferred Thailand insect food, principally when fried, being a very popular snack for locals. Water bugs are also eaten in Thailand, where they are very popular, being frequently found in the small street stands in Bangkok. They are consumed in one piece, after cooking by streaming or frying with a spicy sauce. In addition, they are found roasted or canned for consumption by locals (Redford 1987; Melo-Ruíz et al. 2016).

Eating insects is very popular in Chinese culture, where they have been consumed for more than 2000 years. At present, 324 species of insects from 11 orders are documented as being edible or they are associated with entomophagy in China, but the number of edible insects continues to rise as a consequence of more scientific papers that are being published. Insects are frequently consumed at home or in restaurants all year round. Local restaurants regularly serve edible insects such as locusts, ants, silkworm pupae, bamboo insects, termites, Chinese caterpillar fungus, bees, and wasp larvae (Hu and Zha 2009; Feng et al. 2016, 2018).

In Mexico, some native peoples have been using insects as food for very long ages. The Jumil Festival is a Mexican celebration in which people harvest stinkbugs in the woods to consume them raw or alternatively grounded and mixed with chiles to fill tacos. Stinkbug owes its name to the stink it releases and therefore needs a preparation before being fit for consumption, by soaking in warm water. It is rich in vitamin C and is traditionally eaten in Mexico and Southern Africa. Presently, 535 types of edible insects are used in Mexico, in regions situated in the centre, south, and southeast parts of the country. For example, the natives of Los Reyes Metzontla eat 17 different types of insects, at least. Some species of insects are highly valued as delicacies for Mexicans, having a high demand in markets and urban centres. “Chapulines” (grasshoppers of the genus Sphenarium) are among those insects, being consumed roasted to a crunchy texture and mixed with lime and chile, being bought at street stands or alternatively in markets in Oaxaca. In Mexico, some people eat the so-called “insect caviar,” which corresponds to eggs of a giant ant (the black Liometopum). These eggs are consumed in tacos, after boiling or frying in butter. Alternatively, they are consumed with tortillas in escamoles, which is also a traditional dish (Ramos-Elorduy 2006; Ramos-Elorduy et al. 2006; Acuña et al. 2011).

The leafcutter ant Atta laevigata is traditionally consumed toasted, similar to popcorn or peanuts, in some parts of Colombia and in the northeast Brazil. In the State of Bahia, as in the whole North and Northeast of Brazil, the “coco-bugs” (several families of Coleoptera) are amid the most popular insects among indigenous. People in rural areas obtain these larvae by breaking the coconuts, and these insects, when well fried, are a popular dish among farmers, although many people appreciate them raw. The Suruí Indians, from the Aripuanã Indigenous Park, in Rondônia, Brazil, consume Bruchidae larvae of the species Pachymerus cardo F. and Caryobruchus sp., called “Kadeg” and obtained from the coconut of the Babaçu palm. They can be consumed raw or roasted in its own fat. Fried larvae are highly appreciated as an accompaniment to roasted corn or popcorn. The Yanomamo of Brazil and Venezuela extract and prepare the larvae of Bruchidae that infest the fallen fruits of the palms. In Manaus, Amazonas, Brazil, at the Jungle Warfare Instruction Center (CIGS) of the Brazilian army, soldiers consume Bruchidae larvae present on fruits of various native palms during jungle survival exercises (Ramos-Elorduy et al. 2006).

Tarantula spiders, although technically arachnids, are compared with insects in relation to eating, being consumed in Latin America (Cambodia and Venezuela). They are usually fried in oil and salted or sweetened with sugar, but sometimes other condiments, like garlic, are used to intensify taste. They have a crispy texture and are traditionally sold in the streets of Cambodia. The indigenous Piaroa people, living in Venezuelan jungles, consume roasted goliath bird-eating tarantulas, which can grow as much as 20 cm diameter (Yen and Ro 2013).

In Africa, stinkbugs are decapitated and pressed so as to empty a gland, and after they are cooked and dried in the sun, to prepare an appetizing snack. In southern Africa, in countries such as Botswana, Zimbabwe, or South Africa, the mopani or mopane worm (the moth Gonimbrasia belina’s large caterpillar) is very common and constitutes a good source of food protein. Termites are popular in Australia, West Africa, and some parts of South America, being consumed uncooked, as appetizing snacks, or after preparation, roasted or fried (Redford 1987; Latham 2015).

Meyer-Rochow (2005) presents some cultural roots of practices linked with insect and spider consumption in some ethnic groups of some regions (Northeast India, Papua New Guinea, Australia, and New Zealand). In addition, the reasons for consumption of these foods were addressed. In India, the type of insects consumed varies according to geographical region and is also associated with climate. In Australia, insects are eaten by some aborigine tribe, also varying according to geographical location. In New Zealand, insects are reported as a traditional food for the Maoris ethnic group, whereas in Papua New Guinea people regularly consume a variety of insects and spiders.

6.2 Consumers’ acceptance of insects and insect-based foods

Insect consumption, especially for individuals in many western societies, is still interpreted as a taboo (Sidali et al. 2019). Although they represent an interesting source of high-quality nutrients, insects can provoke some adverse reactions, even disgust, besides being considered as a primitive feeding practice. Nevertheless, in recent years some changes have been observed in the recognition and acceptance of insect-based foods. In particular, the sensory characteristics are important for consumer acceptance, so the sensorial characteristics of edible insects and foods which incorporate insects as ingredients, for example insect flour, are pivotal for minimizing rejection and making them more attractive to consumers (Cheung and Moraes 2016; Mishyna et al. 2020).

Meyer-Rochow and Hakko (2018) reported that, despite the well-documented aversion that people from western societies have towards insects as food, when insects are turned into flour or paste they are more easily accepted by western consumers because they do realize their presence, as compared with products that are advertised as having insects in their constitution.

A research undertaken with Brazilian consumers indicated that the main reason explaining why the participants do not attribute the food status to insects is the difficulty in perceiving and characterizing them as food, associating them with expression like “no food” or “disgusting.” Therefore, production and commercialization of insects as sources of proteins for humans must focus on the barriers of the consumers, by making them believe that it is a good food and linked with pleasant sensations and thoughts. Only then, aspects such as nutritional value, sustainable production, or reduced water footprint will also be included in the decision-making process (Cheung and Moraes 2016). Another study about how Brazilian consumers perceive edible insects showed that men are more prone to consume insects than women. Although it was observed a general preference to consume “disguised” insects, in the form of flour, for example, there were some participants who prefer the whole insect, especially those more familiar with this type of consumption (Schardong et al. 2019).

A study was undertaken with German consumers to examine the factors determining acceptability of edible insects (whole or processed into insect-based foods) (Orsi et al. 2019). The researchers found that there is a low disposition among Germans to try insects, mostly because of psychological and personality barriers including disgust and food neophobia. However, the attitudes were not so strong towards processed insect products, therefore constituting a possible strategy to gradually introduce entomophagy (Orsi et al. 2019).

In the Netherlands, the most important motivations to try eating insect foods are highly variable according to price, taste, availability, and “fit,” which are also factors affecting everyday consumption of commonly consumed more traditional foods. Higher acceptance of insects as food and their related products is more likely for consumers who are categorized as adopters of other novel foods, and which, by this reason, should receive greater attention (House 2016).

A consumer survey was undertaken in some European countries (Germany and Czech Republic in central Europe and Finland and Sweden in northern Europe) to investigate how consumer knowledge affects disposition to buy insect food. The main findings of the study highlighted that the level of knowledge is a determinant of the willingness to purchase insect food; the effects of knowledge were variable according to country or region, differing between countries in central Europe and countries in the northern Europe. Finally, it was also evidenced that the possible marketing of insect foods might be more successful in northern European countries (Piha et al. 2018).

Ghosh et al. (2020) studied the perceptions of Korean and Ethiopian consumers about entomophagy and found that the predisposition of Koreans to eat insect-based foods was substantially higher than that of Ethiopians. Moreover, genders differences were observed, so that male participants on the survey were more prone to eat insects than women. In addition, the results indicated that there is a wrong idea that people from developed countries are not so open to the idea of eating insect as people from developing countries.

Oliveira et al. (2017) produced a flour from cinereous cockroaches (Nauphoeta cinerea) which they added into white bread as a way to enrich the product in protein. The inclusion of 10% cockroaches’ flour led to an expressive increase in protein content, by 133%, while at the same time reducing fat content by 65%. The researchers measured the consumer’s acceptance index and obtained a value over 75% in all sensory attributes evaluated. As for the buying intention, 22% stated they would certainly purchase and 41% stated they would possibly purchase the bread with cockroaches’ flour.

In a work by Megido et al. (2016), four different hamburgers were prepared: beef and lentil burgers, and their counterpart versions with 50% insect (mealworm). They observed that testing by means of hedonic assessments reduced insect neophobia. In addition, the participants rated the attributes of taste and appearance with higher scores for the insect-added burgers when compared with the control. Finally, the insect-based burgers were rated between the 100% meat burger and the 100% vegetable burger.

Recent studies have demonstrated that there is a greater disposition, especially among populations not traditionally entomophagous, to consume products which incorporate grounded instead of whole insects. A work by Cicatiello et al. (2020) investigated the determinants for acceptance of insect-based snacks among Italians, namely products with whole insects versus products that included insect flour as the principal ingredient. Despite the still existing strong cultural barriers, there seems to be a willingness to test some insect-based products among young Italian consumers, because towards those products they do not feel the same level of repulse as for the products where the whole insect is fully visible.

A relevant number of works continue to focus on the use of insects as food or food ingredients for human consumption, either from the point of view of the products’ characteristics or the consumer acceptance. Food neophobia determines to a great extent the consumer’s decision making when they have to opt between unknown new foods or those that he already fully recognizes. However, there are also neophilic consumers, who are willing to try new foods and can develop a good acceptability towards the taste of new foods. It has been reported that the liking for new foods raises as consumers are increasingly exposed to them, and therefore become more familiar with their characteristics (Loss et al. 2017; Guiné et al. 2020a,b).

6.3 New gastronomic trends

Preparation and enjoyment of foods are seen as multi- and transdisciplinary phenomena. From the primary production of animal and agricultural products, until they can be regarded as food, they encompass many operations, including processing, cooking, and the ultimate experience of eating and sensing the product (Fooladi et al. 2019).

According to Traynor et al. (2020), culinary education has an important impact on the attitudes and behaviours towards novel food products, so that individuals with culinary education tend to have a greater overall liking for innovative products.

The perception of insects as food has been gradually establishing in places where they were not traditionally seen as food. Insects have been introduced into high-profile spots, such as culinary events, gastronomic shows, and chef’s recommendations. According to Chef Hal Daniel, an entomophagy expert and Biology Professor at East Carolina University, insects are the green food of the future. There is a recognized role of chefs in introducing insects into gastronomy in the western countries, by making them more popular and seen as trendy and exquisite (Cheung and Moraes 2016; Mishyna et al. 2020).

However, the willingness to try new and unfamiliar food has been shown to be guided both by beliefs regarding a food’s disgusting properties and by interest, where interest in trying new things has been defined as an important motivational aspect in food choice (Martins and Pliner 2005; Sogari et al. 2017). This also indicates that there is great value in increasing our understanding of the factors that make us interested and choose certain foods (Mancini et al. 2019).