7 
7 Industries of Insects
Throughout history, insects have given us many products of great significance, and many of these products have retained their significance to this day. Some are well known, such as honey and silk. Others you may never have heard of or even realized that they originated from an insect, such as the red coloring in your strawberry jam or the glossy sheen on the skins of supermarket apples.
As always in the case of insects, we’re talking about enormous numbers. Even the close to 1.5 billion head of cattle on the planet pale into insignificance when we add up all the livestock in the insect world. According to statistics from the UN’s Food and Agriculture Organization, more than 83 billion honeybees buzz around the world in our service. And every year, upward of 100 billion silkworms sacrifice their lives to provide us with silk.
Honeybees make honey of course, as discussed in chapter 5 (see page 86). But they also make beeswax, a soft mass produced by special glands in their abdomens, which they use to build nurseries and warehouses for their honey. Beeswax also has many applications for humans and plays a major role in a mythological tale that will be familiar to many.
In Greek mythology, Daedalus and his son, Icarus, flee Crete using wings that Daedalus has created from birds’ feathers and beeswax. Daedalus cautions his son against the dangers of complacency and arrogance before they set off: if his son doesn’t make enough of an effort, he’ll end up flying too low and the sea will destroy his wings; if, on the other hand, he is overcome by hubris and fails to recognize his own limitations, he will fly too high and the sun will melt the beeswax that holds his wings together (a psychologist might perhaps note that the father would have been better off telling his son what he ought to do instead of teaching him about all the pathways to catastrophe). Young people clearly didn’t listen to their parents in those days, either: Icarus flew too close to the sun, the wax melted, and he crashed into the ocean. But at least he had a sea (the Icarian Sea, which is part of the Aegean) and an island (Icaria) named after him.
Nowadays we use beeswax to make candles and cosmetics rather than wings. The Catholic Church has traditionally been a major consumer because the candles used during Mass had to be made of beeswax. The pale wax was supposed to symbolize Jesus’ body, while the wick at the center represented his soul. The flame that burns when the wax candle is lit gives us light, while the wax candle itself burns down—sacrificing itself, as Jesus did, for humanity. Only the very purest wax could be used for this purpose, and bees scored high on that count: since nobody had observed them mating, they were long assumed to be virgins who lived a life of sexual abstinence. Only in the 1700s was this misapprehension corrected (see page 40), but to this day the candles used for Mass in the Catholic Church must contain at least 51 percent beeswax.
It has become increasingly common to use beeswax in cosmetics such as creams and lotions, lip balm, and mustache wax. Honey is also an important component of cosmetics, by the way. If, say, you make one of the many recipes for homemade honey face masks on the internet, you’ll be glad to hear that you are in illustrious company: the wife of the Roman emperor Nero, Poppaea—who, of course, didn’t have the option of ordering products from the online outlets of the finest French cosmetics companies—made her own face masks from honey mixed with asses’ milk. At least that means it doesn’t matter if you happen to get some on your lips. Indeed, beeswax mixed with vegetable oils is an excellent lip balm.
Beeswax is also used to help oranges, apples, and melons keep better and to make them look shiny and tempting. This familiar foodstuff is applied to the surface of fruits, nuts, and even food supplement pills. A significant amount of the beeswax extracted from hives these days is also used to produce new beeswax frames that are placed back into the hives. A proper thank-you present!
Silk billows beautifully, is strong but light, is cool against the skin, and has a special sheen all its own. It’s an exclusive fabric. It’s hardly surprising that in China, silk from silkworms—the larvae of the Bombyx mori butterfly—was long reserved for the emperor and those closest to him.
The history of silk reads like a tale from the Arabian Nights: it’s exotic yet brutal, and it’s difficult to separate fact from fiction. Two strong women play a central role in the legend. In the beginning, 2,600 years before the Western Common Era, the Chinese princess Lei-tsu was sitting drinking tea under a mulberry tree in the garden of the imperial palace when a silkworm cocoon fell out of the tree and into her cup. Lei-tsu tried to fish it out, but the heat of the liquid dissolved the cocoon, transforming it into the most beautiful thread—long enough to cover the entire garden. In the innermost part of the cocoon lay a tiny larva. Lei-tsu immediately grasped the potential of this discovery and got the emperor’s permission to plant more mulberry trees and breed more silkworms. She taught the women at the imperial court to spin the silk into a thread that was strong enough to be woven, thereby laying the foundations of Chinese silk production.
Silk production would remain an important cultural and economic factor in China for several thousand years. Indeed, the country is still the world’s largest silk producer, and to this day the cocoons are placed in boiling water to kill the larvae and loosen the thin silk threads.
China guarded the secrets of silk for a long time. Eventually, the trading routes known as the Silk Road opened up between China and the Mediterranean countries, where silk was an important product because the Romans loved it. That said, some viewed this new, almost transparent fabric as immoral; indeed, certain people went so far as to claim that silk dresses were practically an invitation to adultery because they left so little to the imagination.
Be that as it may, we might speculate whether it was actually the amount of gold leaving the Roman Empire to pay for the silk that people found immoral rather than the fabric itself—because China’s monopoly on silk production earned the country an enormous income. Consequently people were strictly forbidden to share the secret: an attempt to smuggle out silkworm larvae or eggs was punishable by death.
In the end, the secret came out anyway, and once again a woman played a central role if we are to believe another of the many legends. It is said that a Chinese princess married the prince of Khotan, a Buddhist kingdom in the west of modern-day China that lay along the Silk Road. On her departure, the princess smuggled out silkworm eggs and mulberry tree seeds in her headdress. In that way, the secret spread, the monopoly was broken, and several other countries started to produce silk. Today, more than 200,000 metric tons of silk are produced each year to make clothing, bicycle tires, and surgical thread. Silkworms are still the main producers, although a few other related species are also used.
Silkworms are not the only insects that spin silk. This skill has probably cropped up more than twenty times among insects over the course of evolution. Green lacewings, for example, fasten their eggs onto small stalks of silk. They look like tiny Q-tips, with the eggs like a clump at the end, and their purpose is to stop ants and other starving souls from getting the eggs. Caddis fly larvae spin silken trapping nets in streams, using them to capture small creatures for their dinner; the larvae of certain members of the mosquito family spin a trapping net that they use to gather up spores beneath fungi or to trap small insects. Some fungus gnat larvae are even luminous, emitting a blue-green light; nobody has managed to explain why. Unlike the luminous mosquito larvae in the caves of New Zealand, which are predators and use the light to lure their food into the net, European Keroplatus species seem content to obtain their protein from fungus spores and have no obvious reason to play at being light bulbs.
Among some species of dance flies the males use silk to pack up a delightful “nuptial gift” for the female. The males themselves are not predators—they subsist peacefully on a diet of nectar—but they’ll do anything for their greedy, protein-crazy inamoratas. So they trap an insect (preferably another male, because that reduces the competition for females—two birds with one stone, so to say) and wrap their prey up beautifully in silk produced by special glands on their forelegs. A suitor bearing gifts that he’s even taken the trouble to package himself—it sounds delightful, but the reality isn’t especially romantic. This behavior simply shows the hidden hand of evolution at work, as always. One theory is that the bigger the present and the better the packaging, the more time the male gets to mate. Consequently he transmits more sperm and has a greater chance of passing on his genes. And it’s fantastic for the female to receive a hefty dose of protein, because laying eggs is an energy-intensive business.
But there’s always the odd trickster who’ll try to get the benefits without putting in the effort: some males give the female an empty ball of silk—and then have to get the mating over with pretty fast before the lady discovers she’s been tricked.
We can’t talk about silk without mentioning spiders, even though they are arachnids rather than insects. The group takes its name from the person who became the first spider, according to Greek mythology: a talented weaver called Ariadne, who had the temerity to challenge none other than Athena, the Greek goddess of war and wisdom, claiming to be a better weaver than she. The punishment for her arrogance was to be transformed into a spider. And what an ancestral mother Ariadne turned out to be. Today, we know of more than 45,000 species of spiders. The silk isn’t just to make webs to trap their prey; it’s also a kind of compensation to the arachnids for lacking the wings of their distant relatives the insects, which they can only envy. By climbing up to an airy spot and producing a long silken thread that the wind can catch, small spiders can sail away on the breeze using their own kiting technique.
Spider silk has impressive qualities. On a per weight basis, it is six times as strong as steel, but at the same time it is highly elastic. This is why a heavy fly that blunders into a web can’t simply pass straight through it. Instead, the web gives, a bit like the arresting cables that help fighter planes land on aircraft carriers. This enables thin fabric made of spider silk to halt a flying projectile—a property that can be used to make extremely light bulletproof vests, superabsorbent helmets and a new type of airbag for cars. If only we could learn how to get hold of sufficient amounts of spider silk.
Experiments have shown that it is possible to harvest around 110 yards of silk from a single spider, but it’s when you want to scale up that the trouble starts. Unlike the fat, laid-back silkworm larvae, which think of nothing but eating the leaves of the mulberry tree and spinning silk, spiders are predators who have no qualms about eating one another. So it isn’t especially easy to keep them in captivity in order to set up industrial-scale silk production.
A beautiful golden silk dress woven from the silk spun by golden orb spiders from Madagascar broke records for visitor numbers when it was exhibited in the Victoria and Albert Museum in London in 2012. That’s hardly surprising, because it is a truly remarkable garment that was four years in the making. Every morning, eighty workers collected new spiders. They were hooked up to a small hand-operated machine, where they were “milked” of their silk and then released again in the evening. In all, 1.2 million spiders were needed.
It’s plain to see that this is an unsustainable option for industrial production, so people have started to think along different lines. In 2002, the first “spider goats” saw the light of day. With the aid of gene technology, scientists simply transferred “spinning genes” from a spider to a goat, which then began to produce milk that contained the proteins involved in silk production. This sparked considerable media attention but hasn’t yet yielded any concrete results to speak of. Norway’s neighbors have also thrown themselves into the race to produce synthetic spider silk. The Swedes recently reported that they had produced more than half a mile of thread using water-soluble proteins produced by bacteria. The protein solution solidifies into spider silk when chemical conditions are altered, exactly the same thing that happens at the opening of the spider’s spinnerets.
We’re still a long way from commercial production, and perhaps that’s not so surprising: after all, spiders have had around 400 million years to perfect their silk.
Shakespeare’s plays and Beethoven’s symphonies. Linnaeus’s flower sketches and Galileo’s drawings of the sun and the moon. Snorre’s Sagas and the US Declaration of Independence. What do all these things have in common? They were all written using iron gall ink, a purplish black ink that we have an insect to thank for: the gall wasp. These tiny insects are parasites on plants and trees, and they are most commonly found on oaks. Gall wasps secrete a chemical substance that triggers a growth on the plant that forms a house and pantry around one or several larvae.
There are many varieties of galls. One type that is often used for ink is the oak gall, also known as an oak apple. It does, in fact, look like a small apple—perfectly round with a reddish tinge—except that it happens to be stuck to an oak leaf.
Inside their oak apples, gall wasp larvae lie chomping away on plant tissue in peace and quiet, protected against all foes. Well, only partly, because some parasites have parasites of their own: unwelcome guests who turn up for dinner uninvited and refuse to leave again—such as guest gall wasps, which simply move into other wasps’ galls because they can’t make their own. Worse still are the interlopers that use their long egg-laying stingers to poke their way through the walls of the gall and lay eggs in the very gall wasp larva that is living there. As a result, the insect that hatches out of a gall may be very different from the species responsible for the gall’s creation in the first place.
The walls of the oak gall are stiff with a form of tannic acid. This acid occurs naturally in many plants and trees and is the substance that links your leather jacket with a fine red wine. Tannic acid is crucial for tanning hides and leather, and a master wine connoisseur can distinguish grape varieties and storage methods based on the tannins in a wine.
The first types of ink, made in China several thousand years before the Common Era, used carbon from lamp soot. The soot was mixed with water and gum arabic, a natural gum obtained from acacia trees, which kept the soot suspended in the liquid. But if you were unlucky enough to spill a cup of tea over your writing, your thoughts would be lost forever. Carbon ink was water soluble and easy to wash away—which people also tended to do if they ran short of writing materials and needed to reuse what they had already written on.
Later, people learned to make ink from oak galls mixed with an iron salt and gum arabic. The great advantage of this new ink was that it was nonsoluble: it ate its way into the parchment or paper it was written on. What’s more, it wasn’t lumpy and was easy to make. From the 1100s to well into the 1800s, oak gall ink was the most commonly used kind in the Western world.
If it hadn’t been for the little oak gall wasp, it is far from certain that we would have so many well-preserved and legible documents from the great artists and scientists of the Middle Ages and the Renaissance. If we’d had only lampblack ink, many ancient thoughts, tunes, and texts would have been washed away by water, either because storage conditions were poor or because somebody wanted to reuse the parchment.
Insects provide us with colors other than the brown-black hue of oak gall ink. They are also responsible for a beautiful, deep bright red color that was, for several hundred years, exclusively produced in the Spanish colonies and that is still in use today in both food and cosmetics.
Carmine dye is harvested from the females of a particular species of scale insect (Dactylopius coccus), peculiar creatures the size of a fingernail that are also known as cochineals. Their natural habitat is in South and Central America, where the females spend their entire life on a single spot, wingless and firmly clamped beneath the protective shield of a prickly pear.
The dye was known to both the Aztecs and Mayans long before the arrival of the Europeans, and they bred a variant that yielded a more intense red color. Since this color was both difficult and expensive to produce in late-medieval Europe, dried cochineal bugs were one of the Spanish colonies’ most important wares, valued on a par with silver—because carmine was an intense, powerful red color that withstood sunlight without bleaching. The famous red coats of British soldiers were dyed with carmine, and Rembrandt, among others, used the color in his paintings.
Since the dried insects were small and had no legs and it was before the days of microscopes, Europeans were long uncertain whether the grains of carmine were animal, vegetable, or mineral in origin. The Spaniards kept the secret close to their chests for nearly two hundred years to ensure their monopoly and the vast income the little insect earned them.
Nowadays, carmine comes largely from Peru. The dye is used in many red-colored food and beverage products, such as strawberry jam, yogurt, juice, sauces, and red sweets. You will also find it in various cosmetics, such as lipstick and eye shadow.
What do jelly beans, phonograph records, violins, and apples all have in common? A substance extracted from an insect, of course. It’s a product with an incredible number of applications, yet you have probably never heard about its origins. We are talking about shellac, a resinlike substance that is produced by the lac bug, a relative of the cochineal bug that gives us carmine. There are heaps of these little creatures on the branches of various tree species in Southeast Asia. According to some sources, the name derives from the Sanskrit word lakh, meaning “one hundred thousand,” and refers to the enormous numbers of these bugs that can be found in a single place. (A brief diversion: the same source has it that the Norwegian word for salmon, laks, has the same linguistic origin for the same reason, because of the large numbers of salmon that gather in the mating season.)
There are several species of lac bugs, but the most common “productive” variety is Kerria lacca. Lac bugs are members of the true bug family (see page 28) and spend most of their lives with their snouts stuck into plants—a pretty dull existence. But good heavens, the things this little life has given us humans! One science article went so far as to say that “Lac is one of the most valuable gifts of nature to man.”
The tradition of cultivating lac bugs goes back a long way. The insect is mentioned in Hindu documents from 1200 BCE, and Pliny the Elder described it as “amber from India” in writings dated CE 77. But it wasn’t until the end of the 1300s that Europeans set their eyes on the product, first as a dye and later as a varnish—in other words, a substance to apply to wood to create a glossy, waterproof surface. Furniture, woodwork, and violins were all traditionally treated with shellac.
But shellac turned out to have many more areas of application. For fifty years, from the end of the 1800s right up until the 1940s, shellac was the main ingredient of phonograph records. It was mixed with ground rock and cotton fiber to produce what Norwegians used to call steinkaker, or “stone cakes”: brittle, breakable 78 rpm records. The sound reproduction was so-so, but the early record players—or “talking machines,” as they were known—were tremendous fun. Bear in mind that radio hadn’t yet become common; the world’s first-ever wireless radio broadcast wasn’t transmitted until 1906 in Brant Rock, Massachusetts, and in Norway test broadcasts didn’t start until 1923. So for a long time phonograph records provided the only opportunity to host a “virtual” orchestra or band in your own living room.
Record production was at such high levels in the 1900s that US authorities started to worry, because shellac was also important to the military industry, which used it in detonators and as a waterproof sealant for ammunition, among other applications. So in 1942, the US government ordered the record industry to reduce its shellac consumption by 70 percent.
How do these tiny insects produce a substance with so many varied areas of application: varnish, paint, glazing, jewelry and textile dyes, false teeth and fillings, cosmetics, perfume, electrical insulation, sealant, the glue used to restore dinosaur bones, and a raft of other areas in the food and pharmaceutical industries?
It all starts with thousands of tiny lac bug nymphs settling on a suitable twig. With their sucking mouths, they slurp down plant sap; this undergoes a chemical change inside them and oozes out at the rear as an orange resinlike liquid, which hardens when it comes into contact with air. This forms small, shiny orange “rooftops,” which initially cover only the individual bugs but gradually merge into one giant roof that shelters the entire colony and can cover a whole branch. After shedding their skins a few times, adult scale insects hatch out, then mate and lay eggs, well protected by the roof. The adults then die, and the eggs hatch into thousands of new nymphs, which break through the resin roof and set off to find themselves a suitable new branch.
In order to make shellac, the resin coating must be scraped off the branches. It is then crushed and cleaned of insect fragments, after which it is ready for market as small amber-colored flakes or dissolved in alcohol.
Most shellac production occurs in India these days. The good thing is that small-scale farmers in rural villages are the ones doing the job. Some 3 million to 4 million people, many of whom have few other means of earning money, are estimated to earn their bread from keeping lac bugs as livestock. Moreover, the production helps keep species diversity rich in the “grazing areas” of this tiny domestic animal. One reason for this is that little or no pesticide is used, because that would also put these creatures’ lives at risk.
Don’t those shiny apples in the fruit aisles of your supermarket look delicious? That’s hardly surprising, because they’ve been for a waxing session at the lac bug’s skin care clinic. What happens is this: we humans eliminate the apples’ natural wax coating when we wash them after harvesting. And without wax, apples quickly turn into wrinkly, unappetizing fare that few people would want to sell and even fewer would want to buy. So apples have to be waxed again—and that’s where shellac comes in, like a sort of antiwrinkle cream.
Many other types of fruit and vegetables also undergo a round of shellacking to ensure that they last longer and look more appealing. The substance is approved for use on citrus fruits, melons, pears, peaches, pineapples, pomegranates, mangos, avocados, papayas, and nuts. In 2013, shellac was also approved to buff up hens’ eggs in Norway. The idea is to make the eggs nice and shiny and increase their shelf life.
Shellac also turns up as glazing for various sweets, such as jelly beans, sugar-coated chocolates, lozenges, and the like. This glazing agent also goes by many other names: lacca, lac resin, candy glaze, or confectioner’s glaze.
Shellac is used in cosmetics, too: in hair spray and nail varnish and as a binding agent in mascara. It is also used in pills in capsule form, and not just to make the surface shiny: because shellac doesn’t dissolve very easily in acid, it can be used to make delayed-release pills—in other words, capsules that dissolve only when they reach the gut.
Once you realize just how many strange places this product pops up in, perhaps it no longer seems so peculiar that somebody should call shellac one of the most valuable gifts of nature to man.