James L. Franklin
Chicago, Illinois, United States
|Figure 1 – Khoisan – Igniting a Fire|
On a recent wildlife adventure to the Kalahari Desert in Botswana, our group of adventurers was treated to an afternoon walk with a group of local Khoisan villagers. They were eager to show us how they were able to live off the land. Highlights of that visit included hearing fluent speakers of a “click language,” a demonstration of fire building with collected brush and branches ignited by swirling a stick (no matches), locating edible tubers (figures 1 and 21), and unearthing a scorpion that was eaten on the spot (figure 3). The photograph led me to think about insects as a source of nourishment, a practice foreign to our “Western” sensibility. Scorpions, spiders, and insects belong to the arthropod phylum. To be correct, scorpions are arachnids, not insects. They have four pairs of legs while insects have three.
Of course, we need a learned word to frame our inquiry. Entomophagy, from the Greek éntomon, “insect,” and phagein, “to eat,” seems to have entered our vocabulary only recently, in 1975. Broadly, the term applies to both non-humans and humans. Entomophagy is practiced throughout the animal kingdom, from insects that feed on other insects, to mammals that specialize in eating insects (insectivores such as aardvarks and pangolins), to primates and our closest relatives, the great apes. The versatility of language does not fail us, and we arrive at “anthropo-entomophagy,” human consumption of insects, the subject of this paper.
|Figure 2 – Khoisan – An edible tuber|
Sources vary, but up to 2,086 species are consumed by 3,071 ethnic groups in 130 countries throughout the world.2 If we look at insect consumption across the globe, an interesting pattern emerges. The human consumption of insects is best predicted by closeness to the equator and to tropical regions. The lowest consumption is in locations farthest from the equator.3 The countries where insects are not routinely eaten include the United States, Canada, and members of the European Union. Since entomophagy may offer a means of combating world food shortage and a potential hedge against climate change, it is relevant to ask why Western culture is averse to eating insects. Explanations include: a core disgust associating insects with food spoilage, an aversion to eating recognizable animal parts (insect legs, eyes, and antennae), the view of insects as agricultural pests, and the fear of eating something new or capable of transmitting disease.
The Khoisan of the Kalahari are representative of a globally diminishing hunter-gatherer culture. Before the domestication of plants and animals by Homo sapiens about 10,000 years ago, people survived on natural resources. Over the last century, the study of surviving hunter-gatherer cultures has allowed us to make inferences about the human diet before the advent of agriculture. While men pursued the hunting of game that was both dangerous and uncertain, women gathered reliable sources of food close to their home base, allowing for childbearing and childrearing. The collection of edible insects occurred in this setting and women were more likely to rely on this food source to meet the nutritional demands of pregnancy.
Entomophagy may have been practiced by the earliest members of our hominid lineage. Observations made by Jane Goodall in the 1960s of chimpanzees in Tanzania revealed that they fashion tools to retrieve termites from termite mounds (figure 4). Her work was revolutionary and overturned the uniqueness of man as a tool maker. It also led to the inference that our last common ancestors with the chimpanzee lineage may have consumed insects. Inferences like these and those made from studies of contemporaneous hunter-gatherer societies are intriguing and may be valid, but they are not proof.
The decrease in entomophagy as one moves away from the equator correlates with an ecological phenomenon known as the latitudinal gradient of diversity. The great biodiversity in tropical regions decreases as one moves toward the poles. During the dispersal in two separate waves, our early hominid ancestors, first Homo erectus 100,000 years-ago and then Homo sapiens some 50,000 years ago, had to adapt to this decrease in biodiversity, which included a decrease in insect species available for food. In colder latitudes, they had to depend on hunting and fishing to meet their caloric needs. In 1999, Gene R. DeFoliart compiled a comprehensive summary of the consumption of insects across the globe. His country-by-country overview of insect consumption highlights the nutritional and economic benefits for rural communities.4 He notes that caterpillars and termites (winged sexuals) are the most widely eaten and marketed insects in Africa.
Termites of the genus Macrotermes evolved in Africa 20 million years ago (figure 4). An attractive hypothesis suggests that termite consumption afforded australopithecines and the early members of genus Homo with the nutritional means to support the requirements of their enlarging brains. The most direct evidence supporting this theory comes from bone tool artifacts found at the Swartkrans site in South Africa. The markings on these tools suggest they were used to excavate termite mounds. This phenomenon has been reproduced experimentally using simulated bone tools. An analysis and critique of current methodology into the potential role that entomophagy may have played in the diet of early hominids has been thoughtfully reviewed by Julie J. Lesnik in Edible Insects and Human Evolution.5
One might speculate that an aversion to eating insects followed the spread of the Judeo-Christian tradition across Europe. While Leviticus condemned “winged swarming things that have four legs” as an abomination, the text allowed that “you may eat the following: locusts of every variety; and all varieties of bald locust; crickets of every variety; and all variety of grasshoppers.”6 In the Gospel according to St. Matthew, when John the Baptist preached in the wilderness, “his meat was locusts and wild honey.”7 Examples of insect consumption by the Greeks and Romans can be found in the writings of Aristotle and Pliny the Elder. Aristotle wrote on the natural history of the cicada, noting the most efficient way to harvest them, and found them delicious. A naturalist, Pliny the Elder in the first century CE described how the larvae of the Cossus was highly regarded as food.8
Looking to the future, it is clear from many sources that entomophagy offers a mitigating approach to two of the major problems we face today: food shortage and climate change. This topic has been extensively explored in a number of sources.9 The argument may be summarized under two headings: the nutritional value of insects and the potential for insect consumption to help reduce the production of greenhouse gases (GHG).
|Figure 3 – Scorpion, Kalahari Desert, Botswana|
The world human population is predicted to approach nine billion by 2050. The demand for food will continue to increase, particularly in industrializing nations like China and India and in continental Africa. It is possible that a third of the world’s population will suffer from some degree of food insecurity and outright malnutrition. Insects as a group are comparable or superior nutritionally when compared with other meat or vegetable sources. They provide comparable levels of protein by percentage of dry weight as well as providing essential amino acids. Insects have concentrated in their tissues iron, calcium, zinc, and long-chain essential fatty acids. Meaningful comparisons must be made by studying the nutritional profile of each specific insect. For example, in an analysis based on dry weight, beef is 55% protein, whereas mealworms contain 49% protein. Mealworms and crickets have differing combinations of amino acids. Through a medley of insect species, it is possible to ensure a diet that contains all the essential amino acids. Mealworms and crickets also have less fat than beef but are rich in essential fatty acids.10
The use of edible insects as a major food source might help in our fight against climate change. Insects can be produced more sustainably than traditional livestock, requiring less pastureland, feed, and water. Food conversion ratios are a measure of the efficiency with which livestock convert feed into food for human consumption. Animals with smaller bodies in general have lower food conversion ratios. For cattle the ratio is 10:1, for pork it is 5:1, and for chicken it is 2.5:1. In contrast, crickets have a conversion ratio ranging from 1.47 to 1.84.
Water shortage is another threat of climate change. In the “West,” 80% of water supply goes to agriculture, which includes both crops and livestock. Of this 80%, half is used to produce feed for livestock. It is estimated that producing one pound of beef requires 1000 gallons of water, one pound of pork requires 600 gallons of water, and one pound of chicken requires 150 gallons of water. In general, one pound of insects can be produced with one gallon of water.
It is well recognized that the loss of forests and wilderness to agriculture and grazing reduces photosynthesis, which is an important trap for carbon dioxide (CO2) and replenishes oxygen (O2) in the atmosphere. To produce one pound of beef requires 200 square feet of pasture (2 acres/cow), one pound of pork requires 175 square feet of pasture (2/3 acre/pig), while in general, one pound of insects can be grown in 2 cubic feet of space.11
|Figure 4 – Termite Mound, Kalahari Desert, Botswana|
“Greenhouse gas (GHG) produced by livestock accounts for approximately 18% of global human emissions.”12 As ruminants, cattle are the most important contributors of methane (CH4) emissions. The output of GHG in five insect species for CO2, CH4, and nitrous oxide (N2O) has been measured and found to be lower than cattle. Crickets and mealworms produce less GHG than traditional livestock species. Termites, however, produce large amounts of methane as they consume cellulose-dense food.
One of the hurdles to overcome if entomophagy is to play a significant role in addressing food security and climate change will be the “ick factor.” This issue has received considerable attention.13 The “West” and industrializing nations will have to adjust their attitude or risk being perceived by developing nations to be preaching—“let them eat cake [bugs]”—while continuing their love affair with beef. Insects are on an evolutionary path far removed from humans, and when compared with livestock or birds, are less likely to transmit disease. Safety issues with regard to production and preservation will have to be addressed. It should be noted that those with allergies to shellfish may be unable to consume insects. If we look to a world where entomophagy plays an important role in addressing food insecurity, a varied group of insects will have to be selected that may be adapted to mass production. The methods of production, storage, packaging, and distribution will all have to be solved.
- The figures included in this article are from the author’s personal collection.
- Julieta Ramos-Elodury, Anthro-entomophagy: Cultures, evolution and sustainability, Entomological Research, 39 (5): 271-288, September 2009.
- Julie J. Lesnik, Not just a fallback food: Global patterns of insect consumption related to geography, not agriculture. American Journal of Human Biology 29(4) e22976, 2017.
- Gene R. DeFoliart, Insects as Food: Why the Western Attitude is Important. Ann. Rev. Entomology, 44:21-50, 1999.
- Julie J. Lesnik, Edible Insects and Human Evolution, University Press of Florida, 2018. This publication provides a thorough analysis of the research methods and literature relevant to this subject. Chapters six and seven are devoted to the subject of early hominids and members of the genus Homo.
- The Jewish Study Bible, Adele Berlin and Zvi Brettler, editors, Oxford University Press, 1999, p. 230 (Leviticus 11:20-23).
- The Bible: Authorized King James Version with Apocrypha, Oxford World Classics, 1997. The Gospel According to St. Matthew 3:4, (p. 5).
- Julie J. Lesnik, Edible Insects and Human Evolution, p. 27.
- Arnold van Huis, Potential of Insects as Food and Feed in Assuring Food Security, Annu. Rev. Entomol. 58:563-83, 2013; Julie J. Lesnik, Not just a fallback food.
- Scott Solomon, Why Insects Matter: Earth’s most essential species, The Great Courses, 2021, Lecture 12, “Insects as food for people.”
- Daniella Martin, Edible, New Harvest, Houghton Mifflin Harcourt, Boston – New York, 2014, pp. 28-29.
- Arnold van Huis, Potential of Insects.
- Gene R. DeFoilart, Insects as Food: Why Western Attitude is Important, Annu. Rev. Entomology, 44:21-50, 1999; Julie J. Lesnik, Edible Insects and Human Evolution chapter 2, Understanding the Ick Factor.
JAMES L. FRANKLIN, M.D., is a gastroenterologist and associate professor emeritus at Rush University Medical Center. He also serves on the editorial board of Hektoen International and as the president of Hektoen’s Society of Medical History & Humanities.