Insects in certain taxonomic groups have played an important role in the history of human nutrition. Although their use as food has long been taboo in almost all Western cultures, their traditional use in tropical and subtropical countries continues to be widespread and to provide significant benefits—nutritional, economic, and ecological—especially for rural communities. The potential benefits of continued or wider use are obvious enough that there seems to be a lessening of the negative attitude in the West.
The type of metamorphosis undergone by an edible species determines which life stage(s) is likely to be consumed. In the insect orders with simple or incomplete metamorphosis (i.e., the Hemimetabola), the life stages usually eaten are the nymphs and/or adults. These orders include the Orthoptera (grasshoppers, locusts, katydids, crickets), Isoptera (termites), Heteroptera (true bugs), and Homoptera (cicadas). Legs, wings, head, and any other hard parts are usually removed before cooking. Orders having complex or complete metamorphosis (i.e., the Hemimetabola) include the Lepidoptera (moths, butterflies), Coleoptera (beetles, weevils), and Hymenoptera (bees, ants, wasps). The life stage usually eaten is the larva, but sometimes it is the pupa or, rarely, the adult.
The insects used as food are, for the most part, clean-living in their choice of food and habitat. Most feed on leaves or other parts of plants. Some of the coleopterous and lepidopterous larvae are wood borers in either dead or living trees and bushes; some, such as cicada nymphs, feed on plant roots. Some hemipterans and coleopterans are aquatic, and some of these and other edible insects are preda-ceous. Some hymenopterans such as wasps provision their nests with insect prey upon which the young feed. Some edible species have other aesthetic qualities. Some African termites are architects, erecting earthen cathedral-like termitaria that may rise to heights of 3 or 4 m or more. Cicadas and crickets are songsters.
To collect wild insects for use as food, one should be knowledgeable about which local species are edible, particularly in Western cultures in which insects are not among traditional foods that are widely recognized. Some insects secrete toxins or sequester toxic chemicals from food plants or serve as a source of injectant, ingestant, con-tactant, or inhalant allergens. Bright colors, especially red, or showy behavior such as slow, deliberate flight may suggest that an insect contains toxins, or is unpalatable, and should be avoided.
There are many environmental and ecological ramifications relevant to the use of insects as food. Because of the large number of insect species and the consequently wide variety of plants used as hosts, in general, insects are potentially capable of converting a much wider range of vegetation and waste substances into animal biomass than are the animals currently considered acceptable as food by Western cultures. Many plants that either are not used efficiently or are not used at all in food production serve as hosts for edible insects. In Mexico, it has been suggested that some plants that are widespread and characteristic of arid regions, but of limited food value, such as mesquite, madrono, and some cacti, could be used for cultivation of their associated insects, the weevil Metamasius spinolae and the larva of the skipper butterfly, Aegiale hesperiaris. The protein and fat content of these insects is many times higher than that of their plant hosts. In general, insects also are higher in their food conversion efficiency than are other food animals when both are fed diets of high quality (see the house cricket, Acheta domesticus).
ORTHOPTERA (GRASSHOPPERS, LOCUSTS, KATYDIDS, CRICKETS)
Family Acrididae (Shorthorned Grasshoppers)
Grasshoppers and locusts are included among the foods of almost every culture having any history of using insects as food. In southern Africa, before there were crops to protect, the arrival of a locust swarm, some of which were dense enough to block out the sun, was hailed with rejoicing as a time of harvest. Villagers collected them in the evenings after the swarms had alighted and were benumbed by the cool of the night. The locusts were roasted or boiled or, when plentiful, dried and crushed in mortars to make a much appreciated flour. Sometimes the flour or porridge was mixed with honey to make a sort of cake. Early reports noted that indigenous populations with access either to these vast locust swarms or to winged termites soon grew “visibly fatter and in better condition than before.” Grasshoppers were also an important food of Indian tribes in western North America. Various methods of harvest were used, but, most frequently, the grasshoppers were encircled by a number of people and driven into a pit previously dug or onto a bed of coals. Thus, slightly roasted, they could either be eaten or dried and kept for winter food.
In more modern times, within the past 20 years, grasshopper harvest has at one time or another replaced insecticide spraying in parts of Mexico, Thailand, and the Philippines. Sphenarium is the grasshopper genus of greatest commercial food importance in Mexico. The rice grasshopper, Oxya velox, was formerly widely eaten in Japan and Korea. Following reduced use of pesticides on rice in both countries, it is again increasing in numbers. Known as inago in Japan, it is now found in supermarkets as a luxury item; known as metdugi in Korea, it is considered a health food.
Family Gryllidae (Crickets)
Several species of crickets are important as food. In Southeast Asia, Brachytrupes portentosus lives in tunnels that are about 30 cm deep, usually one cricket per hole, and comes out only at night. They feed on young plants and are an agricultural pest. They are collected by digging, by filling the holes with water, or as they fly around lights at night. After the wings are removed they are eviscerated, then fried, grilled, or put into curry as a substitute for meat. They are sold by villagers in the markets. In the market at Chiang Mai in Thailand, the shopkeeper takes the crickets live from a plastic bag and spits them longitudinally from head to abdomen on a bamboo stick, three or four crickets per stick. They are then fried in oil in front of shoppers.
Another species of Brachytrupes, the sand cricket (B. mem-branaceus), occurs widely in eastern Africa. Like its cousin in Asia, its presence is indicated by a small heap of soil pushed out from its burrow. It is usually collected by the women and children, and as many as 100 can be collected in a day. It has been said of the sand cricket, “When well prepared it is considered a delicacy, for it turns an ordinary meal into a dinner.” In Zimbabwe and likely elsewhere, B. membranaceus is one of the species that has increased in numbers in recent years because it is particularly suited to the new kinds of agroecosystems. It is now a significant pest in sand-soil fields, and it is sold in urban markets.
The cricket most readily available to Western insect gourmets is the cosmopolitan house cricket, A. domesticus ( Fig. 1 ), which is widely reared commercially as food for pets and other small animals. Studies in the United States led to estimates that this cricket, when kept at temperatures of 30°C or higher and fed diets equal in quality to those used in bringing conventional livestock to market condition, shows a food conversion efficiency about twice as high as those of broiler chicks and pigs, four times higher than sheep, and nearly six times higher than steers when losses caused by dressing percentage and carcass trim are taken into account. In addition, female crickets have much higher fecundity than beef animals; each cricket lays 1200- 1500 eggs over a period of 3-4 weeks. In beef production, by contrast, four
FIGURE 1 Mass-reared edible house crickets, A. domesticus.
animals exist in the breeding herd for each market animal produced, thus giving crickets a true food conversion efficiency close to 20 times better than that of beef.
ISOPTERA (TERMITES)
Termites are a highly regarded food throughout sub-Saharan Africa. They are eaten raw, fried, or roasted and are found widely in village markets. The fungus-growing termites of the genus Macrotermes (family Termitidae) are most widely used as food.
The large winged adults (sexual forms) are collected as they emerge from the nests on their mating flights at the beginning of the rainy season. They are strongly attracted to light and this behavior is utilized in harvesting them. The high termitaria of some species of Macrotermes are a spectacular feature of the African landscape; they are even considered private property in some areas. In southern Congo (Kinshaza), the termitaria average three to five per hectare and may cover 4.3-7.8% of the miombo woodland. The flora of the mounds is characteristic and quite different from that of the surrounding miombo, thus increasing habitat diversity. This diversity is in danger of being lost, however, because in suburban regions and towns, the characteristic flora and fauna are being destroyed and the mounds converted to other uses.
Winged termites are a rich source of fat; analysis of M. subhyalinus in Angola yielded an energy value of 613 kcal/100g and M.falciger in Zimbabwe a value of 761 kcal/100g on an ash-free basis. Protein and fat content of the latter were shown to be 41.8% and 44.3%, respectively, on a dry weight basis. In addition to the winged adults, soldier termites are also eaten.
The high regard in which winged termites are held in Zambia has been documented by Silow in 1983 and appears typical for other countries in Africa: “The Mbunda, Nikangala, Lucazi, Luvale, Cokwe, and Yauma generally agree that the meat of Macrotermes spp. [winged sexuals] is better than meat of animals, birds, [or] fish. Perhaps one or another of the edible caterpillars is comparable with them, but most of my informants are of the opinion that [Macrotermes] or honey is the best existing food.” Silow notes that there are a few people who simply do not like termites and that some missionaries have condemned termite eating as a heathen custom. But he further states that Bemba, Namwanga, Nyanja, and Nsenga whom he has met unanimously declare that Macrotermes winged adults “are more delicious than anything else, or at least among the most delicious dishes.”
HETEROPTERA (TRUE BUGS)
Family Belostomatidae (Giant Water Bugs)
A giant water bug, Lethocerus indicus, is widely eaten in Southeast Asia and is especially popular in Thailand, where it is known as ma-lang-da-na. The bugs are 5-8 cm in length and fierce predators on frogs, large insects, and small fish. They are caught using nets or at lights, to which they are attracted. There are many methods of preparation, including roasting, frying, steaming, and grilling. After cooking they may be pounded and used for flavoring sauces and curries. The males secrete a fragrant liquid from two abdominal glands and are made into a much-prized sauce to accompany meat and fish. In the markets, males sell for three or four times the price for females. Artificial water bug flavoring is now produced, but people still prefer to eat the real bugs.
Imported bugs (known as mangda) from Thailand and extracts of the bug (known as mangdana essence) can be found in Southeast Asian food shops in California. They are popular with Thai and Laotian customers who use them to make a bug paste called nam prik mangda prepared by mashing a whole bug with salt, sugar, garlic, shallots, fish sauce, lime juice, and hot Thai capsicum peppers. The nam prik man-gda is commonly used as a vegetable dip and as a topping for cooked rice. The extracts known as mangdana essence can be used as a substitute for a whole bug in the preparation of nam prik mangda, but they are considered inferior in taste to that prepared from a whole bug.
Families Corixidae (Water Boatmen) and Notonectidae (Backswimmers)
The famous Mexican “caviar,” also known as ahuahutle . is composed of the eggs of several species in these families. These insects formerly bred in tremendous numbers in the alkaline lakes of central Mexico and were the basis of aquatic farming for centuries. Lake water pollution has now reduced their numbers. The eggs are harvested by what amounts to setting oviposition trap lines. Bundles of shore grass are tied together and weighted with a stone and then distributed by canoe. They are left in place for about 3 weeks during which the adult bugs swim up and lay their eggs on the submerged grass. The bundles are then collected, brought to shore, and dried in the sun. When dry, they are shaken and the eggs fall off. The “caviar” is a true delicacy that appears on the menus of the finest restaurants in Mexico.
HOMOPTERA (CICADAS AND OTHERS)
When there is an emergence of one of the species of periodical cicadas (family Cicadidae), many Americans, for whatever reasons, seem to regard them as legitimate fun food. During a recent (1990) emergence in Chicago and northern Illinois, for example, the Chicago Sun-Times carried several articles, the second of which began: “Millions of tasty, entrees-if-you-dare will be available for the gathering during the next month in northern Illinois, and some Chicagoans will want to know how cicada fanciers prepare them.” Several recipes were provided. Articles described cicada biology and how to prevent damage caused by egg laying on very young plants and urged Chicagoans to forego the use of insecticidal sprays. There were many radio reports, a cicada hotline, and even Time magazine published a recipe.
There are six species of periodical cicadas (Magicicada) in North America, three with a 13-year cycle and three with a 17-year cycle. The nymph remains in the soil, feeding on the roots of various plants until ready for the final molt. It then digs itself out of the ground, climbs the nearest tree or shrub, and attaches itself firmly. The adult lives for a month or longer. The so-called dog-day cicadas, such as those of the genus Tibicen . have shorter life cycles, but even they require at least 4 years. Cicadas are eaten in many countries, but probably most widely in the countries of southeastern Asia.
LEPIDOPTERA (BUTTERFLIES, MOTHS)
Lepidopterans reach their maximum food importance in Africa where, in many countries, more than 20 species are consumed. In the southern part of Congo (Kinshasa), for example, caterpillars of at least 35 species are consumed.
Family Saturniidae (Giant Silkworms)
In 1980, Malaisse and Parent analyzed 23 species (17 of which were Saturniidae) eaten by humans, using samples that were prepared in a manner identical to that preceding their culinary preparation and then dehydrated. Crude protein content averaged 63.5%, kcal per 100 g dry weight averaged 457, and most species proved to be an excellent source of iron, 100 g averaging (in 21 species analyzed for iron) 335% of the daily requirement. In Angola, the sat-urniid caterpillar Usta terpsichore was found to be a rich source of zinc, iron, thiamine, and riboflavin.
Probably the best known of the edible caterpillars is Gonimbrasia belina, the so-called mopanie worm, which is widely eaten in southern Africa. The South African Bureau of Standards has estimated annual sales of mopanie through agricultural cooperative markets at about 40,000 bags, each containing 40 kg of traditionally prepared, dried caterpillars. This total represents only those entering reported channels of commerce and does not include those privately collected and consumed or sold. The caterpillars, up to 10 cm in length, grip the host plant tightly and cannot be shaken off; they must be picked by hand. A good picker in an average infestation can collect 18 kg per hour. In areas where they are abundant and bulk-dried, they are first eviscerated and then roasted for 15 min before being spread out to dry. About 2 days are required for the product to become dry enough for storage.
The mopanie caterpillar is an important food item and is actively traded not only in South Africa but also in Botswana and Zimbabwe and is exported by the ton to Zambia. From extensive studies in South Africa, Dreyer and Wehmeyer concluded in 1982 that “the consumption of mopanie caterpillars can to a substantial degree supplement the predominantly cereal diet with many of the protective nutrients.” The amino acid composition of the dried caterpillars is relatively complete, with high proportions of lysine and tryptophan (which are limiting in maize protein) and of methionine (limiting in legume seed proteins). There is increasing concern in South Africa that the mopanie caterpillar might be collected to the point of extinction.
In Malawi, G. belina and another saturniid, Gynanisa maia, still occur abundantly in Kasungu National Park; the larvae are in season from mid-October to December, a time of year when food stocks of families living near the Park are running low. The caterpillars are nonexistent outside the Park because of the absence of host trees, which have been displaced by extensive agriculture. A study has shown that opening Kasungu National Park to controlled sustainable use, such as caterpillar harvest, by local people can reduce the problems of poaching in parks and other protected areas. Similarly, of ecological benefit, observations in Zambia have shown that there are very few late bushfires in areas where the caterpillars of Gy. maia are found. Fires late in the dry season cause considerable damage by killing trees, reducing regrowth, and increasing erosion. The caterpillars are a highly prized food, and in areas where they are abundant they provide the incentive for people to burn early, thereby protecting the caterpillars and enhancing woodland regeneration. There are other examples in Africa where protection of caterpillars as a food resource enhances biodiversity.
Family Bombycidae (Silkworm Moths)
A by-product of the silk industry, pupae of Bombyx mori remain after the silk is reeled from the cocoons. These pupae are widely sold, often canned, in markets in Eastern Asia. In China, the pupae, along with waste materials from the reeling factories and from the silkworm rearing, are also used as fish food in pond-fish culture. Canned pupae are exported, especially from Korea, and can be found in Asian food shops in the United States.
Family Cossidae (Carpenterworms, Leopard Moths)
Many insects were important foods for the Aborigines of Australia and among the most prized were the witchety or witjuti grubs, several species of root-boring cossid larvae belonging to the genus Xyleutes. Tindale conducted in 1953 the definitive study on these insects and stated, “Aborigines with access to witjuti grubs usually are healthy and properly nourished. …Women and children spend much time digging for them and a healthy baby seems often to have one dangling from its mouth in much the same way that one of our children would be satisfied with a baby comforter.” Over a period of several months spent observing nomadic Pitjandjaras in the Mann and Musgrave Ranges, it was noted that part of nearly every day’s diet consisted of these larvae. Tindale states elsewhere that the taste of witchety grub, “when lightly cooked in hot ashes, would delight a gourmet.”
Recently in Australia there has been an explosion of interest in native, or “bush tucker,” foods, including witchety grubs and other insects such as bardi grubs (Cerambycidae) and honey ants. Bush food is increasingly found in restaurants frequented by tourists, and topic stores are well stocked with topics on bush tucker. Witchety grubs are on the menu of the posh restaurant Rountrees on Sydney’s North Shore; the chef says of them, “They have a nice, nutty flavor when roasted.”
Family Megathymidae (Giant Skippers)
The larva of the giant skipper butterfly, Aegiale hesperiaris, known as gusano blanco de maguey, or the white agave or maguey worm, is in demand by people of all social classes in Mexico. Whereas campes-inos with access to maguey plants can collect their own larvae to eat or to sell, restaurants in the larger towns and cities charge as much as U.S. $25 per plate. The gusanos are served fried or roasted in butter, chili, or garlic sauce. They are also exported as gourmet food. Two other edible insects are associated with the maguey. The pink worm of the maguey, Xyleutes redtenbachi (family Cossidae), also called the red agave worm or gusano rojo de maguey, is the larva used in bottles of tequila. They are sold in the markets and are also used to season sauces or they may be roasted or fried with salt and eaten in tacos. Along the maguey’s roots are often colonies of ants, which serve as a source of the prized escamoles, or so-called ant eggs, which actually are ant pupae.
Family Pyralidae (Wax Moths, Grass Moths)
Taylor and Carter wrote in 1976 as follows: “Larvae of the greater wax moth (Galleria mellonella) are tasty and, fortunately, easily reared, hardy and odorless. If only they were commercially available, we would probably have centered most of our recipes around them. They are our favorite insect. They are thin-skinned, tender, and succulent.
They would appear to lend themselves to commercial exploitation as snack items.” The authors note that the larvae, when dropped into hot vegetable oil, immediately swell, elongate and burst, looking then not like an insect, but like popcorn, and having the flavor of potato chips, corn puffs, or the like. These larvae, known as wax moths, are now available from various dealers in North America.
COLEOPTERA (BEETLES, WEEVILS)
Family Curculionidae (Snout Beetles, Weevils)
The larvae of palm weevils, several species of Rhynchophorus, also called palm worms, are widely eaten and greatly esteemed. A modern cooktopic on Cameroon cuisine includes a recipe describing “coconut larvae” as “a favorite dish offered only to good friends.” The major species are Rhynchophorus palmarum in the Western Hemisphere, R. phoenicis in Africa, and R. ferrugineus and R. bilineatus in southeastern Asia, Indonesia, and the western Pacific. All of these species have long been semicultivated or “farmed” by indigenous peoples and are excellent examples of how harvests of edible insects from natural populations can be increased by intentional creation of additional breeding sites. Cultivation consists basically of cutting down palms and leaving the logs in the forest with the expectation that larvae will be ready to harvest from the decaying pith 1-3 months later. The flavor of the sago grub (R. ferrugineus papuanus) in Papua New Guinea has been described as “tender and sweet with a slightly nutty flavor.” The insect not only sells regularly in local food markets and is bought by foreigners as well as Papua New Guineans, it also is the focus of annual “grub festivals.” Palm weevils are also destructive pests of palms and, in the Western Hemisphere, are vectors of the nematode Bursaphelenchus cocophilus, the causal agent of red-ring disease. Although insecticides have been used in attempts to control the weevils, emphasis is on cultural methods. With the palm worms considered such a delicacy, it has been suggested it might be possible to combine increased production with more efficient recycling of dead and diseased palms and as part of reduced-pesticide integrated pest management (IPM) programs and disease control on coconut and other palms.
Family Scarabaeidae (June Beetles, Dung Beetles, Rhinoceros Beetles)
Of the several edible groups within this family, the most interesting is probably the subfamily Dynastinae or giant rhinoceros beetles, particularly the genus Oryctes. Three species, including two that breed mainly in dead standing palms, are eaten in Africa, whereas Oryctes rhinoceros is a major pest of palm in Asia and the western Pacific. Main hosts of the adult beetles are coconut, oil, and date palms, whereas the larvae live in a variety of dead but not yet decomposed plant material, including dead standing coconut palms, stumps and logs on the ground, and other types of decaying wood, as well as compost, dung heaps, rotting straw, rotting coconut husks, coffee and cacao pulp waste, refuse from sugar cane factories, ricemills, and sawmills, and other wastes from agricultural processing. Control of rhinoceros beetles is based on sanitation and cultural practices similar to those recommended for Rhynchophorus weevils, suggesting that Oryctes might also be incorporated into palm IPM programs, recycling an endless variety of tropical wastes into animal protein and fat.
Family Cerambycidae (Longhorned Beetles)
In this family, it is the larvae, primarily, that are used as food. They are wood borers in both living and dead trees and in logs and stumps. They have long life cycles, a year or more, so would not be good candidates for mass-rearing under controlled conditions. A major genus, with edible species, is Batocera in Asia.
Family Tenebrionidae (Darkling Beetles)
Tenebrionids have a bad reputation as pests of meal, flour, and other stored and packaged cereal foods, but, despite this, the yellow mealworm, Tenebrio molitor, has been reared by zoos, aquaria, and commercial dealers as food for birds, fish, and a variety of small animals since at least the 18th century. Their easy availability makes them one of the insects most commonly recommended for inclusion in recipes in the West. There is a problem of quinone contamination in some tenebrionid-infested food products, but this appears to be much less a problem in T. molitor than in species of the genus Tribolium.
HYMENOPTERA (ANTS, BEES, WASPS)
Family Apidae (Honey Bees)
Honey is prized by many indigenous cultures, and bee pupae/ mature larvae, sometimes called “grubs” or “brood,” are often as highly prized as the honey. In southeast Asia, three species of wild bees, Apis dorsata, A. florea, and A. indica, are important sources of honey, wax, and brood. A. dorsata is the largest species and its nests, in the higher branches of large trees, may be up to 2 m in diameter. Its honey is also the most expensive, but honey from A. florea is most commonly found in the markets. People often eat the grubs uncooked, but they are also fried or put into soup. In Latin America, the grubs of A. mellifera and of species in several genera of stingless bees (subfamily Meliponinae) are used as food, and some of the bees, in Brazil and Mexico, for example, are semidomesticated. Bees, including stingless species, are also important in Africa. In some places, such as the Congo (Kinshasa), honey and brood are still harvested by cutting down the tree although the practice has been much criticized. Apiculture in the United States is based on the introduced honey bee, A. mellifera, and it has been suggested that, because of its good public image, this species might be a valuable tool in helping to reshape attitudes toward insects as food in the United States.
Family Formicidae (Ants)
Many kinds of ants serve as food in different parts of the world and they are generally considered delicacies. In Colombia, for example, toasted leafcutter ants (genus Atta) are said to constitute the highest attainment of Colombian cookery. A campesino, by collecting and selling Atta ants, can earn during the 3-month season the equivalent of a year’s wages for the average rural worker. The genus is restricted to the Western Hemisphere. Only the alates are eaten, the large females being especially prized. They are collected as they swarm from the nest by the thousands on their mating flights during the early part of the rainy season. Two species, A. cephalotes and A. sexdens, are the most widely consumed, being relished across northern South America, with the former extending up into Mexico.
Fungus gardens grown on chewed leaf fragments are tended in the underground chambers of the large nests of the leafcutter ants. The fungus converts cellulose into carbohydrates that can be metabolized by the ants, thus allowing them to tap the virtually inexhaustible supply of cellulose in their forest environment. Forest trees are able to survive the grazing pressure of the ants, but the ants are serious pests of many cultivated trees and other crops when nests are located at the edges of forests adjacent to cultivated areas.
Escamoles are eaten by all social classes in Mexico and the ants have been described as the most enjoyable and expensive edible insect in the markets. Although called “ant eggs,” escamoles are mainly mature larvae/pupae of two species of the genus Liometopum, L. apiculatum and L. occidentale var. luctuosum. Digging out the underground nest where the escamoles are found is very labor intensive. After harvest of ants from the nest (two or three times per year between February and June), the nest is covered with nopal, dried grass, and fresh weeds to maintain an environment suitable for survival and regrowth of the colony. People who collect escamoles, known as escamoleros, sometimes make more money during the harvest season than other rural people make during the entire year. The Liometopum ant is considered such a special treat in Mexico that it is the subject of songs, dances, and festivities.
Honey ants are a source of sweet treats in Mexico (species of Myrmecocystus) and Australia (several species in the genera Camponotus and Melophorus). Specialized worker ants, called repletes, store the honey in the abdomen, which may become the size of a small marble. They are eaten by grasping the head of the ant and sucking the honey from the abdomen. In Australia, Camponotus infla-tus develops the largest repletes and they are considered a great luxury by the indigenous population. The repletes are found in galleries in the underground nests, where they are immobile and must be fed by the workers. Some aborigines expend much time and effort digging for the repletes but they only partially dig up the nests so as not to destroy the colonies and thus to preserve this valuable resource.
