Overstory #245 - Edible forest insects

Food insects for sale at Chanthaburi, Thailand, market

Introduction

In the broadest sense, insects have enormous economic value in terms of the ecological services they provide. A recent study in the United States, for example, found that the annual value of insects’ services amounted to more than US$57 billion. The study found that native insects are food for wildlife that supports a US$50 billion recreation industry, generate more than US$4.5 billion in pest control and pollinate crops worth US$3 billion (Losey and Vaughan 2006). If such a study were expanded to include the entire world, the total figure indeed would be staggering.

In addition to the ecological services provided by insects, there is also a long historical relationship between insects and human culture that extends back to antiquity. In the nineteenth century, useful insects were studied in considerable detail and were divided into the following seven categories: 1) insects producing silk; 2) insects producing honey, wax, etc; 3) insects as sources of dyes; 4) insects producing manna (sap or juice exuded by a plant pricked by an insect); 5) edible insects; 6) insects as sources of medicine; and 7) insects as ornaments (Bodenheimer 1951). The foregoing categories are not mutually exclusive because many useful insects fit into more than one category, but in all cases there is a close linkage to ecological services.

The eating of insects appears to be culturally universal, only varying with location, insect populations and ethnic group. It is very likely that progenitors of modern humans in Africa ate insects as part of their diet; the living primates of today consume certain insects with gusto. Exactly how insects (which are not obviously edible) became human food cannot be determined with any certainty. One plausible scenario is that harvesting and eating wild honey led to the collecting and consumption of bee brood (honey, eggs, larvae and pupae in the hive) as a source of protein. This discovery could have led to sampling other insect larvae and pupae (and, perhaps later, adults) that were encountered. These were presumably adopted, over time, as normal, ritual or emergency food sources.

Wherever forest insects are part of the human diet, they have generally been collected from the wild. In most cases, minimal management of forest vegetation has been practised in association with the exploitation of forest insects, and actual domestication of insects thus far has been limited to only a few species such as silkworms and bees. The most commonly eaten insect forms are larvae and pupae, usually with little or no processing of the insects before they are consumed.

Edible forest insects and their food uses

Worldwide, nearly 1 700 insect species are reported to be used as human food. Table 1 identifies them according to taxonomic orders, common English names and number of species. Four insect orders predominate, in rank sequence: Coleoptera, Hymenoptera, Orthoptera and Lepidoptera, accounting for 80 percent of the species eaten (Ramos-Elorduy 2005).

Table 1. Number of edible insect species reported in the world (Source: Ramos-Elorduy, 2005)

Edible forest insects represent rich sources of protein for the improvement of human diet, especially for individuals suffering from poor nutrition because of a protein deficit. Gram for gram, insects often contain more protein and minerals than meat. In fact, nutritionists represent the leading group of researchers in food insects, motivated by a desire to remedy the problems associated with protein-deficient diets.

Interaction between edible forest insects and forest ecosystems

Insects, edible and non-edible alike, are key life forms in forest ecosystems, functioning as pollinators, aiding in the decomposition of dead plants and animals and aerating soil through their burrowing. Insects are important food sources themselves for birds, reptiles, etc. and even provide food directly to carnivorous plants such as the Venus Flytrap (Dionaea muscipula). In some cases, mutualistic symbiotic relationships have evolved; for example, between ants and acacia trees, where apparently in exchange for nutritious leaf sap the ants protect the leaves from leaf-cutting caterpillars.

The scientific identities and details about the life cycles of many forest insects are not known. Forest degradation and clearing may unintentionally disrupt the life cycle of an insect species and could result in its extinction. Globally, this represents the leading cause of insect extinctions. Insects account for the greatest amount of biodiversity in forests, but are the least studied of the biota.

A few edible insects enhance their habitat in specific ways. For example leaf-cutter ants in South America, cultivate “fungus gardens” that convert cellulose into carbohydrates; termites in Africa increase local plant species diversity because some plants can only grow on termite mounds (DeFoliart 1997).

Overexploitation of food insects for socio-economic purposes is a danger in some areas. In Hidalgo, Mexico, field studies revealed that out of about 30 species of insects used as food, 14 species are under threat as a result of current levels of commercialization. Previously, insects primarily had been gathered for local subsistence purposes. Because edible insects are not recognized at the national level as a food resource, there are no regulations on the exploitation of natural populations. The culture of edible insects would seem to be the most practical remedy because their care is simple and has minimal environmental impact (Ramos-Elorduy 2006, 2005).

A recent study by Samways (2007) identified six basic interrelated principles to guide synthetic conservation management of insects. They are to: 1) maintain reserves; 2) maintain as much landscape heterogeneity as possible; 3) reduce the contrast between remnant forest patches and neighbouring disturbed habitats; 4) promote the concept of land sparing outside reserves; 5) simulate natural conditions and natural disturbance; and 6) connect similar patches of quality habitat with protected corridors.

All projects or programmes aimed at promoting edible forest insects should carefully ascertain the conservation status of the insect species directly involved, to avoid risk of contributing to species extinctions. The World Conservation Monitoring Centre (WCMC) in the United Kingdom maintains separate searchable animal and plant databases, accessible on the Internet, containing the identity of species of conservation concern, meaning they are under some level of threat of extinction in the wild. For those species identified, information is provided on the accepted scientific names, common names, geographic distribution, conservation status and related information. Species that do not appear on WCMC lists are assumed not to be under threat. The WCMC database can also be used to verify the conservation status of insect host plant species.

Commercial potential of edible forest insects

The capturing, processing, transporting and marketing of edible forest insects provide important income and livelihood opportunities for an undetermined number of people around the world. Traditionally, these activities were all locally based and largely underrecognized. Recently, however, more sophisticated and wide-reaching marketing and commercialization of edible forest insects have been advanced, including attractive packaging and advertising. Some advocates believe that creating a wider market for food insects could provide an economic incentive for conserving insect habitats.

Published research thus far has paid little attention to the subject of marketing and commercialization of edible forest insects in Asia and the Pacific. The absence of economic data represents a serious constraint to the commercial development of edible insects.

Realizing the commercial potential of edible forest insects must go hand-in-hand with one or more of the following: 1) increased production of wild edible insects through expansion or intensification of the harvests; 2) adoption of forest management practices to enhance productivity; 3) steps toward insect ranching and domestication. These and other topics are addressed in a recent book, Ecological implications of minilivestock (Paoletti 2005). This book represents a clear benchmark in the state of knowledge about edible insects and is the most significant technical study on the subject since the comprehensive Insects as human food (Bodenheimer 1951).

Existing practices to gather forest insects for local subsistence purposes must not be impacted negatively by commercialization. In fact, commercialization may increase the quantity of edible forest insects available for local consumption and thereby provide positive nutritional benefits, as well as create local employment opportunities. Development of edible forest insects must be considered with respect to local, domestic, interregional and international markets because each presents a different set of challenges and requirements for success. In the absence of research results, the extent to which edible forest insects possess commercial potential is difficult to ascertain and generalize about because contemporary dietary habits vary so widely among different populations and ethnic groups.

Insect exploitation and forest management

Insect collection activities generally have a nominal impact on forests and management practices involving timber and non-wood forest products. The minimal impact is likely because edible insects are simply collected from forests, most often on a small scale.

Among land managers, there is little knowledge or appreciation of the potential for managing and harvesting insects sustainably. There is almost no knowledge or experience in manipulating forest vegetation or harvest practices to increase, maximize, or sustain insect populations. Indeed, as many insects cause massive damage and mortality to valuable commercial trees and crops, virtually all insects are considered undesirable pests by many farmers and forest managers. What knowledge does exist in these respects is often held by traditional forest dwellers and forest-dependent people.

Despite this lack of formalized knowledge, the great diversity of forest habitats harbouring edible insects presents an array of opportunities for innovative management of food insects so as to simultaneously contribute to maintaining habitat diversity for other life forms. DeFoliart (1997) suggested five general approaches to protecting forest biodiversity, focused on the insect populations, as follows:

• Enhance forest management by taking into consideration the wishes and needs of local people. A good example is to be found in Central Africa where seasonal burning practices are essential to sustain caterpillar populations that represent a traditional food item.
• Allow sustainable exploitation by local people of edible insects within otherwise protected areas to reduce illegal poaching pressures. For example, the collecting of caterpillars in Malawi woodlands.
• Reduce the use of pesticides in agriculture by developing efficient methods of harvesting pest species that are also traditional foods, such as grasshoppers.
• Increase overall productivity by developing dual product systems, where appropriate, which accrue economic and environmental benefits. Examples are silk for fabric and silk moth larvae and pupae for food; honey as a sweetener and honey bee brood for food.
• Reduce organic pollution by recycling agriculture and forestry wastes into food or feed, using palm weevils and fly larvae as the processors.

References

Bodenheimer, F.S. 1951. Insects as human food. The Hague, Netherlands, Junk. 352 pp.

DeFoliart, G.R. 1997. An overview of the role of edible insects in preserving biodiversity. Ecology of Food and Nutrition, 36(2/4): 109-132.

Losey, J. & Vaughan, M. 2006. The economic value of ecological services provided by insects. Bioscience, 56(4): 311-323.

Paoletti, M.G., ed. 2005. Ecological implications of minilivestock. Enfield NH, USA, Science Pub. 648 pp.

Ramos-Elorduy, J. 2006. Threatened edible insects in Hidalgo, Mexico and some measures to preserve them. Journal of Ethnobiology and Ethnomedicine, 2: 51 (online journal)

Ramos-Elorduy, J. 2005. Insects: a hopeful food source. In M.G. Paoletti, ed. Ecological implications of minilivestock, pp. 263-291. Science Pub., Enfield NH, USA.

Samways, M.J. 2007. Insect conservation: a synthetic management approach. Annual Review of Entomology, 52: 465-487.

Original Source

This article was excerpted from the original with the kind permission of the publisher:

Patrick B. Durst, Dennis V. Johnson, Robin N. Leslie and Kenichi Shono (Eds). 2010. Forest insects as food: humans bite back. Proceedings of a workshop on Asia-Pacific resources and their potential for development, 19-21 February 2008, Chiang Mai, Thailand.  FAO, Bangkok, Thailand.

Author Contact Information

Dennis V. Johnson, 3726 Middlebrook Ave, Cincinnati OH 45208 USA. Email: djohn37@aol.com

Related Editions of The Overstory

• The Overstory #241: Forests for food and nutritional security
• The Overstory #222: Forests and human health in the tropics
• The Overstory #169--Forestry and sustainable livelihoods
• The Overstory #158--Forest Culture
• The Overstory #139--"Hungry season" food from the forests
• The Overstory #128--Wild Foods in Agricultural Systems
• The Overstory #127--Food Security
• The Overstory #109--Cultural Landscapes
• The Overstory #41--Microlivestock