Greenhouse gas (GHG) production, as a cause of climate change, is considered as one of the biggest problems society is currently facing. The livestock sector is one of the large contributors of anthropogenic GHG emissions. Also, large amounts of ammonia (NH₃), leading to soil nitrification and acidification, are produced by livestock. Therefore other sources of animal protein, like edible insects, are currently being considered. An experiment was conducted to quantify production of carbon dioxide (CO₂) and average daily gain (ADG) as a measure of feed conversion efficiency, and to quantify the production of the greenhouse gases methane (CH₄) and nitrous oxide (N₂O) as well as NH₃ by five insect species of which the first three are considered edible: Tenebrio molitor, Acheta domesticus, Locusta migratoria, Pachnoda marginata, and Blaptica dubia. Large differences were found among the species regarding their production of CO₂ and GHGs. The insects in this study had a higher relative growth rate and emitted comparable or lower amounts of GHG than described in literature for pigs and much lower amounts of GHG than cattle. The same was true for CO₂ production per kg of metabolic weight and per kg of mass gain. Furthermore, also the production of NH₃ by insects was lower than for conventional livestock. This study therefore indicates that insects could serve as a more environmentally friendly alternative for the production of animal protein with respect to GHG and NH₃ emissions. The results of this study can be used as basic information to compare the production of insects with conventional livestock by means of a life cycle analysis.

Throughout history humans have manipulated their natural environment for an increased predictability and availability of plant and animal resources. Research on prehistoric diets increasingly includes small game, but edible insects receive minimal attention. Using the anthropological and archaeological literature we show and hypothesize about the existence of such environmental manipulations related to the procurement of edible insects. As examples we use eggs of aquatic Hemiptera in Mexico which are semi-cultivated by water management and by providing egg laying sites; palm weevil larvae in the Amazon Basin, tropical Africa, and New Guinea of which the collection is facilitated by manipulating host tree distribution and abundance and which are semi-cultivated by deliberately cutting palm trees at a chosen time at a chosen location; and arboreal, foliage consuming caterpillars in sub-Saharan Africa for which the collection is facilitated by manipulating host tree distribution and abundance, shifting cultivation, fire regimes, host tree preservation, and manually introducing caterpillars to a designated area. These manipulations improve insect exploitation by increasing their predictability and availability, and most likely have an ancient origin.

Many of the most nutritionally and economically important edible insects are those that are harvested from existing agricultural systems. Current strategies of agricultural intensification focus predominantly on increasing crop yields, with no or little consideration of the repercussions this may have for the additional harvest and ecology of accompanying food insects. Yet such insects provide many valuable ecosystem services, and their sustainable management could be crucial to ensuring future food security. This review considers the multiple ecosystem services provided by edible insects in existing agricultural systems worldwide. Directly and indirectly, edible insects contribute to all four categories of ecosystem services as outlined by the Millennium Ecosystem Services definition: provisioning, regulating, maintaining, and cultural services. They are also responsible for ecosystem disservices, most notably significant crop damage. We argue that it is crucial for decision-makers to evaluate the costs and benefits of the presence of food insects in agricultural systems. We recommend that a key priority for further research is the quantification of the economic and environmental contribution of services and disservices from edible insects in agricultural systems.

Insects used as food and medicine are receiving increased attention. There is a need to scrutinise recent estimates of which and how many insect species are used as we have noticed inappropriate assessments and overestimations. We review the contemporary list of edible insects of the world published online by Wageningen University and compiled by Ijde Jongema since it is widely used in the literature. Each of the 2403 entries were scrutinised, including checking name validity, verifying insect usage in cited references, and categorising each entry. Our revision indicates inappropriate assessments and inclusions such as spiders (not insects) and insect products (e.g., honeydew) when the insect itself is not used. With relevant and accepted definitions, we provide a critical assessment and estimate of the number of food insects (1611) and medicinal insects (81), which is lower than Wageningen University and Jongema’s estimate of 2111 “edible insects”. We acknowledge that our critical assessment may also be an overestimate or an underestimate and deserves further scrutiny, and we encourage a more practical use of a database of food and medicinal insects with our suggestion for a querying online curated database. We conclude that making accurate estimates is a difficult feat but that inappropriate assessments can and need to be avoided.

Madagascar has a long history of using Orthoptera as food and feed. Our understanding of the biological diversity of this resource, its contemporary use, and its future potentials in Madagascar is extremely limited. The present study contributes basic knowledge of the biological diversity and local uses of edible Orthoptera in Malagasy food cultures. Data was collected with key informants in 47 localities covering most of the ecoregions of Madagascar and corresponding to 12 of the 19 ethnic groups. Orthoptera are consumed throughout Madagascar. We report 37 edible Orthoptera species, of which 28 are new species records of edible Orthoptera in Madagascar and 24 are new species records of edible Orthoptera in the world. Most species are endemic and occur in farming zones. Children are the primary collectors and consumers of edible Orthoptera. The insects are eaten both as snacks and main meals. Edible Orthoptera are primarily collected casually and marketing is rare, with the notable exceptions of the large cricket Brachytrupes membranaceus colosseus and during locust outbreaks (e.g., Locusta migratoria). The use of Orthoptera as feed seems rare. Further investigations of cultural and personal preferences are required to assess the future potential roles of Orthoptera in Malagasy food habits.

Insects are increasingly promoted as a sustainable protein alternative for human consumption. Yet consumers have shown varied levels of acceptance, especially in countries without a tradition of eating insects. Even in countries where people traditionally eat insects, farmed insects might be considered novel foods if they are not the same species locals traditionally consume. In this work, we measured acceptance of a farmed cricket ( Gryllus madagascariensis ) as food at eight primary schools in the central highlands of Madagascar, a country with a long tradition of eating insects but not this species. We evaluated the role of education as a strategy to increase acceptance of insects as food. We also assessed whether education interventions affect children’s willingness to try cricket-based products, comparing three five-minute education interventions : historical overview of entomophagy in Madagascar, nutritional benefits of consuming insects, and preparation of cricket-based meals. Out of the 483 children, 73% had consumed insects in the past. The percentage of children willing to eat novel farmed crickets in school meals jumped from 16% before the education sessions to 87% after the education sessions. Education based on preparation of cricket-based meals was the most effective, as 86% of the reluctant children changed their minds. Finally, we found strong evidence that males were more willing to try insects than females before and after education. Our results are in line with past studies, and underscore the importance of education in promoting insect consumption. The drastic increase in the proportion of children willing to try insects suggests that barriers to consuming farmed insects are low in countries with a tradition of insect consumption and can be overcome through education. Our study supports the acceptability of novel farmed insects as an alternative protein solution to combat malnutrition in children in developing countries like Madagascar.