Eat the Beetles!: An Exploration into Our Conflicted Relationship with Insects

by David Waltner-Toews

  Species successfully reared on a large scale and sold for both domestic consumption and export: Acheta domesticus (house crickets) worldwide; Gonimbrasia bellina (mopane caterpillars) in sub-Saharan Africa.

  Species with a long history of domestication by humans and also sold commercially as food: Apis mellifera (honey bees) and Bombyx mori (silkworms).

  Species not traditionally consumed by humans that are currently farmed on a large scale, intended for use as food and feed: Tenebrio molitor (mealworms) and Hermetia illucens (black soldier flies).

  Having listed the criteria for which insects they wanted to consider, the authors then set inclusion criteria, which required that the studies were based on whole, unfortified, uncooked insects, tested at a stage in which they were usually eaten —adults, pupae, larvae, or brood. They also wanted the results on an as-eaten, not dry-weight, basis. Since a lot of animal feeds are prepared on a dry-weight basis, this criterion excluded a lot of studies. In the end, they found no usable data for stink bugs, wasps, and rice grasshoppers.

  Given the criteria, their review would have excluded a 2010 report from Japan that found that silkworm pupae were about 56 percent protein by dry weight (compared to the 18 percent on an as-eaten basis reported by Payne et al) and had an amino acid profile that would satisfy WHO requirements for proteins appropriate for human consumption.22 The author of the 2010 report concluded that silkworm pupae “are good sources of high quality protein and lipid and have an α-glucosidase inhibitor, DNJ, which may retard the absorption of carbohydrates and reduce post-prandial hyperglycemia.”

  Payne’s review found considerable variations within and between species. For instance, although the protein content of house crickets and honey bees was about 15 grams per 100 grams of edible tissue, and for mealworms 21 grams per 100 grams, in each case the variations around those averages were 8–9 grams per 100 grams. Similarly, weaver ants were about 11 grams of fat per 100 grams of insect, and the mealworms were about 15 grams of fat per 100 grams, but in both cases the variations were so large that I am unsure what “average” means. Since these were whole animals that were tested, the researchers had expected less variation than they found.

  Protein and fat contents differ somewhat between pigs, chickens, and cows of course. Some of this variation is based on their genetics, what they are fed, and how they are managed, but much of it comes down to what is being tested: hamburger versus lean steak versus liver, or eggs versus thighs. Since variation among cuts of meat is not relevant to testing insects, which are eaten whole, Payne’s review suggested that the variation for major components such as proteins and fats was mostly an artefact of nonrandom sampling and small numbers of insects sampled. It may have also been that these insects, not having been genetically selected for their nutritional values, actually do have large variations of protein and fat content.

  Despite the variations in study type and results, Payne and her co-researchers did venture to make a few generalizations: palm weevil larvae and termites are high in saturated fats, while crickets and silkworms are relatively low. Most insects, especially honey bees, termites, weaver ants, and palm weevils, were sufficiently high in iron that they could be “recommended as a food source to combat iron deficiency.” Similarly, crickets and mealworms, being high in zinc, could be combined with iron to protect against iron deficiency. High copper levels in termites, palm weevils, and mealworms could be problematic, as could the high saturated fats in palm weevils and termites. Variation in micronutrients such as iron and calcium reported for insects may reflect genuine variation based on small sample sizes (think of comparing six haphazardly met people in a shopping mall), differences in geographical origin, and what the insects were fed.

  A second literature review, by Verena Nowak and her colleagues at FAO in Rome, was focused more on gathering data for an international database and, as far as I could tell, cast a wider net, but summarized and reported results on only one insect — Tenebrio (mealworms).23 Again, the study reported the nutrient content in grams per 100 grams of “edible portions.”

  Nowak’s data on mealworms showed protein levels ranging from about 14 to 22 grams per 100 grams, which is within the range reported by Payne and her colleagues. Nowak’s numbers on fat ranged from about 9 to 20 grams per 100 grams, of which 20–60 percent were polyunsaturated fats. Nowak and her colleagues further stated that according “to the thresholds for food labels [set by the World Health Organization and FAO] . . . T. molitor larvae are a source of calcium, zinc and high in magnesium; pupae are a source of magnesium; and adult mealworms are a source of iron, iodine, and magnesium, and high in zinc.”

  They also noted that these conclusions could be influenced by the practice of “gut loading,” which involves “feeding nutrient-dense feeds in order that the nutrients [such as calcium] in the gastrointestinal tract complement the nutrients contained in the insect’s body.”

  When we eat insects, as when we eat arthropods (including shrimp and shellfish), we are, with a few exceptions (such as lobsters), eating the whole animal — gut, shit, and all — so that gut loading can strongly influence the final products in terms of both nutrition and food safety. Shellfish are often put into clean seawater for a few days to flush out impurities, a process called depuration. Similarly, among societies where insects comprise an important part of the traditional diet, wild-caught terrestrial insects are often cleaned, de-gutted, and boiled before eating.24

  Other original research papers describe mopane caterpillars as good sources of all the essential amino acids, linoleic acid, alpha-linolenic acid, and many essential trace minerals critical to normal growth, development, and health maintenance. Like many larval forms of insects, the mopane caterpillars are generally reported to have higher fat and protein content than the adults, and seem to compare well with chicken and beef. Payne and a different group of researchers also studied trace minerals in insects sold at market in South Africa.25 They discovered that the mopane caterpillars had a surprisingly high level of salt, especially as sold in markets, where they were measured as high as 2,600 milligrams per 100 grams. The salt content of mopane caterpillars and manganese in termites led the authors to caution that “salt should be limited in commercial products; and that further research is required to determine whether common serving sizes of termites may put consumers in danger of manganese poisoning.”

  Although many studies have demonstrated the laboratory- determined nutrient content of insects, there remains the question of whether those nutrients are in a form digestible for humans. In a December 2015 interview on the BBC, Oxford biologist Dr. Sarah Beynon wondered whether Europeans, not having eaten insects for a very long time, might have lost the ability to digest them in ways that make their nutrients available.26 The inability to digest chitin, for instance, has been mentioned by some skeptics as an impediment to the availability of proteins, fats, and micronutrients from insects. Insect exoskeletons are built up out of chitin, the second most common biopolymer (after cellulose) in the world. Is chitin, like cellulose or lignin in plants, just indigestible baggage — the suitcase the bug lives in, if you will — that comes along with eating insects?

  Newer nutritional claims have not been as well investigated as the protein, fat, and micronutrient content of commonly eaten insects. If we wander into the shopping malls of diet and health claims and counterclaims, for instance, we come across reports that chitin is not only an important source of fiber, but also an essential part of a healthy, cancer-free life.

  These claims about chitin could be dismissed as fantasy if there weren’t a number of scholarly reviews reporting on the antioxidant, antihypertensive, anti-inflammatory, anticoagulant, antitumor, anticancer, antimicrobial, hypocholesterolemic, and antidiabetic effects of chitin and its derivative chitosan. Much of this research was done in the lab and in vitro, and focused on chitin that had somehow been processed, but if replicated in other contexts it would open up new possibilit
ies for medicinal insect products that go far beyond food security.

  One partial answer to Beynon’s question about digestibility comes from a 2007 research report documenting the presence of chitinase, the enzyme that enables an animal to digest chitin, in the gastric juices of twenty of twenty-five Italian patients being examined at a medical clinic in Padua.27 Although 5–6 percent of healthy Caucasians do not seem to have the ability to digest chitin, levels of chitinase are reported to be much higher in people from sub-Saharan Africa, particularly those who live in poor socioeconomic conditions. The presence of the enzyme not only speaks to the issue of digestibility today, but is also one piece of evidence from which some have inferred that early humans probably also ate insects.

  Even if chitin is not fully digestible, the research literature suggests that it could be a very useful source material for high-tech insect processors like Ynsect. In a similar biotech vein, in 2016 a team of laboratory researchers reported on a study of the “milk” produced by Diploptera punctata (the Pacific beetle cockroach),28 which — like the tsetse fly — gives birth to live young. Protein crystals in the “milk” of these beetles have three times more energy content than the same amount of buffalo milk, which is richer than cow’s milk. Buffalo milk is used for ghee in India and mozzarella cheese in Italy. I suspect that we are not likely to see pasture-fed cockroaches lined up in a barn for milking, nor a worldwide craze for cockroach mozzarella, but this work does open up the prospect of new bioactive insect-based products.

  Given all the scientific cautions about the variation and uncertainty of measurements, are insects as good for people to eat as the new entomophagists suggest? It depends. These data, and the wide variations reported, should give us pause when we’re making general claims about the superiority of insects. Payne and her colleagues, recognizing these uncertainties, suggest that honey bees, termites, weaver ants, and palm weevil larvae could be added to diets to combat iron deficiency, especially if complemented with house crickets and mealworms, which are relatively high in zinc. Finally, while termites and palm weevil larvae are packed with energy and protein, they also have relatively high saturated fat contents and may thus be less than ideal as primary food sources in populations among whom cardiovascular disease is a problem.

  When making health claims, the ingredients are of course important, but not all eating is about the list of ingredients. Indeed, most of the benefits of foods have to do with the social contexts in which they are eaten and the ecologically complex relationships connecting how they are grown, processed, and transported from the land where they are raised to our mouths. The notion of fortifying local foods with micronutrients and vitamins, or of using nutrient-dense garnishes, has a well-established role in almost all cultures, as does the practice of eating seasonally appropriate foods. The Amazonian Tucanoan people, for instance, have traditionally eaten insects in quantities inversely proportional to the availability of fish and game; used in this way, entomophagy has made a significant contribution to stabilizing their protein intake.

  If done well, working with traditional cooks and local food producers, this combination of garnish and supplements may combine the best of the ingredients with food preferences and nutritional concerns, creating an insect-based version of the Mediterranean diet. Some innovative chefs in Kenya, Nigeria, and Mexico have already enriched maize flour with termites and baked bread fortified with African palm weevils, wheat buns enriched with termites, and maize-based flatbreads enriched with ground mealworms.29

  For some of us, however, our concerns have less to do with our personal health and more to do with whether these foods are healthy for the planet our kids and grandkids will inherit. Sometimes, those outcomes are in conflict with each other.

  OB-LA-DI, OB-LA-DA

  The Last Green Hope?

  Happy ever after in the market place

  The Beatles’ bouncy, singable tune “Ob-La-Di, Ob-La-Da” paints a scenario in which romance, happiness, domesticity, family life, and gender relationships are worked out in lives based on a local market economy and music bands.

  In an April 2016 Motherboard article titled “How Eating Insects Empowers Women,” writer Matt Broomfield asserts not only that raising and selling insects empowers women, but also that “ten kilogrammes of feed produces six kilogrammes of edible crickets, but just one kilogramme of beef” and that insect farming “creates just 1 percent of the greenhouse gases generated by farming an equivalent mass of beef or pork.”30

  This is the ideal, the aspiration, of the new entomophagists. Insects will no doubt make interesting and important contributions to the sustainability and diversity of human diets around the world, but how those contributions play out in real time will be more complicated, I fear, than the glossy promotional literature suggests. Having accepted that insects are at least as good, nutritionally, as the best of our other meat options, let’s explore the ecological aspects of this utopian bug-eating paradise further.

  First of all, it’s important to note that most of the social and ecological arguments in favor of entomophagy are based on farming, not foraging, insects. The basic argument is that a global shift from farming and eating the usual suspects (cows, pigs, chickens) to eating insects (crickets and mealworms, mostly) will decrease the human ecological footprint and mitigate climate change impacts, even as it provides sustainable food security for seven or eight or nine billion people. These assertions sound very attractive. The question is: are they true?

  One way to begin to disentangle the probable reality from the improbable claims is by analyzing pieces of the problem and hoping that one can fit the pieces back together. That’s the conventional way of doing science. It doesn’t always work, but it is a place to start.

  Often, when people are advocating for one kind of meat over another within a farming system, they use a measure called a Feed Conversion Ratio, or FCR for short, which allows for comparison of how many kilograms of feed it takes to produce a kilogram of steak versus how many it takes to produce a kilogram of chicken or cricket. A higher number means you need more feed to produce the same amount of output — meat, milk, eggs, crickets, and so on. A 2015 study31 compared the FCR for Acheta domesticus (domestic house crickets) fed poultry feed or food waste with the FCR for carp (the fish, not the diem), chicken, pork, and beef. If we look generally at how many kilograms of dry feed it takes to produce a kilogram of edible meat, then crickets, carp, and chickens are in the same ballpark — between 1.3 (crickets on poultry feed) and 2.3 (chickens on chicken feed); pork is at 5.9 and beef at 12.7. These data suggest that crickets are at least no worse than carp or chickens. But the published studies report FCRs that are as low as 5 for cows, 3 for pigs, and even lower for farmed fish. The problem is that FCRs vary according to the quality of what the animals are being fed. The higher the quality of the feed, the better (lower) the FCR. What if we focus on grain-fed farm animals — say, chickens versus crickets — and look at their efficiency at converting protein in the feed to protein in the meat? Here, chickens and crickets are about the same.32 At what point, a skeptic might ask, does the cultivation and processing of crops for crickets cause them to lose their ecological advantage?

  To begin to explore that, we need to look beyond FCR, which is not the only measure of how “green” insects are compared to other livestock.

  Consider, for instance, the issue of greenhouse gas (GHG) emissions. Some insects produce greenhouse gases, and different ways of farming insects or foraging for them have different implications for GHG emissions. The question of whether raising insects makes a smaller contribution to the overall total than the production of larger livestock, such as cattle, remains. Food-related greenhouse gas production is not simply a function of adding up the number of cows and crickets and comparing their collective average fart and burp volumes.

  The authors of a 2014 article on “food-demand management” argued that “it is imperative to find ways to achie
ve global food security without expanding crop or pastureland and without increasing greenhouse gas emissions.”33 Most of the major organizations that work on livestock agriculture, such as the International Livestock Research Institute, based in Nairobi, and FAO,34 admit that even if livestock-rearing offers poor farmers a path out of poverty, and even if that livestock has become ecologically essential in many cultivated landscapes, the kinds of large-scale agriculture developed in European-diaspora countries is simply not sustainable. We don’t have enough water. We don’t have enough land. What few can agree on, however, is how to increase food supplies to meet the demands of increasing human populations while striving toward some reasonable global semblance of social and economic equity without at the same time destroying the planet. For the European diaspora to lecture their former colonies about what they should or should not eat seems at best uncharitable, and at worst, hypocritically cynical. Can insects save us from this quandary?

  On December 11, 2015, during the COP21 climate change negotiations in Paris, the BBC posted an interview with chef Andrew Holcroft, of the Welsh restaurant the Grub Kitchen, and his partner, Oxford biologist Dr. Sarah Beynon.35 The piece was titled “How Eating Insects Could Help Climate Change.” The interviewer, BBC Persian’s Sahar Zand, repeated claims made by others that the amount of greenhouse gas released by producing 200 grams of steak is the same as that released by producing 20 kilograms of edible insects, which is an order of magnitude more conservative than Matt Broomfield’s assertion.

  Greenhouses gases may be emitted by livestock themselves (as in cow burps or termite farts), or by the methods used to produce them (industrial, grain-fed versus free-range and pasture-fed). For animals being grown for food, the question is how much GHG is produced per unit of weight gain. Under at least some experimental conditions, insects appear to be the winners. These conclusions, however, need to be reexamined in the context of the production systems being promoted and the landscapes on which they depend.