Mysterious, miraculous and rich world of insects
• There is a fortune of natural wisdom to be found among the vast empires of these tiny beings
AChristmas beetle smacks repeatedly into the television. More than a few incessant flies circle the braai. A moth, flitting around the light bulb, careens noisily and nonstop in a lampshade. A cockroach scurries along the kitchen skirting board and disappears into the pantry.
These and similar familiar irritations shape our predominant view of insects, and there is probably a can of Doom or a similar product in almost every SA household. But, as expressed by John Berger in his 1972 book Ways of Seeing, “the relation between what we see and what we know is never settled”. With the planet in dire shape, it’s high time we understand unseen forces and look closer at the small things.
Mike Picker, UCT emeritus professor of biology specialising in entomology, has been doing precisely this his entire life. “As a child, I would run after every insect, and ever since I’ve been obsessed with them,” he says. His knowledge is a window into a world within the world.
It took a decade to research and write Picker’s latest coauthored book, Southern African Moths and their Caterpillars. Extraordinarily, it features more than 10,000 of the 11,000 or so known lepidoptera species in Southern Africa, lepidoptera being the order, or classification, of moths and their larval stage caterpillars. This is just a small proportion of the world’s estimated 160,000 different species of moths, second only to beetles in sheer diversity. Astonishingly, moths make up about 15% of today’ sknown insect species, and 10% of all species of life on earth.
Metamorphosis from caterpillar to moth is a real-life miracle. A caterpillars can live for a few weeks or a few years. Its sole purpose is to get enough food to transform its body into a pupa. In pupa stage the whole body collapses into a soup; each species of moth has a genome that is complex enough to code for two very different organisms
— the caterpillar and the adult moth. Metamorphosis into a butterfly or moth is a truly radical transformation in which wings are grown, the chewing mouthparts of the caterpillar discarded in favour of a coiled proboscis, and the entire organ and tissue system rebuilt to a new plan.
In a dramatically changing world, where humans don’t generally cope well, lepidoptera give us a transformation template. How adaptable are we, really, in comparison to these marvels of the insect world? Why should we care?
Gross, we think, when we see a fat caterpillar chewing our roses. Yet it seems every Generation Z woman has, or aspires to get, a butterfly tattoo. We love or loathe insects without understanding and appreciating what they do, or simply respecting them as creatures.
Indisputably, insects are crucial to Earth’s systems and its ecological health. Dr Floyd Shockley, overseer of the entomology collection at the Smithsonian National Museum of Natural History in Washington, DC, the US, admits to running out of time and patience for people who ask, “What’s the point of mosquitoes?” or “What’s the point of cockroaches?” Exasperation aside, he has a pithy answer: “Without mosquitos, you impact the diets of larger invertebrates. Without those larger invertebrates, fish [or birds] have nothing to eat. At a certain point, you’re going to reach something that matters to people.”
If you enjoy an occasional sweet treat, like, for example, Woolworths’ Chuck les flavoured yoghurt, you should know that the gloss on the chocolate and the sheen on the jelly bean is often thanks to an insect, the kerria lacca scale bug whose secretions on the bark of certain trees in Southeast Asia are used extensively in cosmetics, hardware resins, and as coatings in food and pharmaceutical products. So beetle juice is real, usually listed in the fine print of ingredients as shellac.
If this is difficult to digest, consider that in the not too distant future humankind may need to rely on insects as a significant primary food source. Insect farming is already big business and is projected to be a $6.3bn industry by 2030.
In his book The Insect Crisis, environmental writer Oliver Milman details the ways in which the Anthropocene is triggering the decline of insect populations — habitat destruction, climate change, habitat destruction, pesticides, pollution, even electric light — and what this loss may mean in the future if it continues, pessimistically portraying an unnatural, monochrome world. We should think about our food, too, because most crops require pollination by insects, meaning that ants, bees, beetles, flies, moths and butterflies play a critical role in agriculture.
Without them, farmers would need to rely on windpollination, so cereals like maize, rice and wheat would be even more commonplace on tables. For dessert? Chocolate lovers may be dismayed to know that cocoa crops are pollinated by a dozen different species of biting midges — relatives to the flies we hate sitting in our kitchen and those responsible for causing horrible diseases.
Envisaging bland meals 30 years from now is an overdramatisation, because though 75% of the variety of agricultural crops are pollinated by insects, not all of these are wholly reliant on insects. Further, these represent only a third of worldwide crop yields. Overall, without insects as pollination agents, projections are that global production would fall 5% in higher-income countries, and 8% in low-tomiddle-income nations.
Still, writes Hannah Ritchie in an authoritative data-drive assessment on the Our World In Data website, “It’s unfortunate that the wildlife we care least about provides us with the most functional value. We favour the bears over the insects, despite relying on the latter much more,” she notes. “There is nowhere that this is more obvious than food production.”
Some entomologists disagree with the issues, projections and conclusions in The Insect Crisis. But there is scientific consensus that interfering or messing with the balance of nature, including by harming minuscule creatures, may open a Pandora’s box. Everything is connected, hence the Butterfly Effect in chaos theory, which holds that a minute change in one state of a non-linear system may cause a huge effect in a later state. Unsurprisingly, then, insects, according to the subtitle of Milman’s book, are the Tiny Empires That Run the World.
Everything has value and means something, even if we can’t easily see or grasp what it is.
Ephemeral beauty
Children love ladybirds, which may account for loveliness as their collective noun. But butterflies are probably the most attractive insects to adults. “Literature and butterflies are the two sweetest passions known to man,” wrote Vladimir Nabokov, one of the 20th century’s most influential literary figures and himself a butterfly collector. Indeed, through the centuries famous poets such as the Romanticists John Keats and William Wordsworth, Emily Dickinson and Robert Frost connected butterflies within imagery of beauty, fragility, and the fleetingness of life.
Modern literature is littered with insect references. In Ann Patchett’s State of Wonder, set in the Amazon, insect life is woven into the story as part of the hazard and the quest. In Mayflies by Andrew O’Hagan the title is a metaphor for shortlived joy followed by tragedy (a mayfly is a species of dragonfly without a mouth; an adult lives for just one day, shifting nutrients within aquatic ecosystems as it flits from one plant to another). Walden, the famous book by 19th-century American naturalist and poet Henry David Thoreau, has a section on his observation of “a bellum, a war between two races of ants, the red always pitted against the black, and frequently two red ones to one black”.
And artists’ wholehearted fascination with butterflies began at least as far back as the 17th-century Dutch Golden Age, encapsulated in the works of Rachel Ruysch, Otto Marseus van Schrieck and Maria Sibylla Merian. It was Merian who first documented metamorphosis and corrected the belief that insects spontaneously generated from mud and waste material. Later, the impressionist master Vincent van Gogh painted a significant number of works featuring butterflies, including an 1889 piece, The Giant Peacock Moth, starring Europe’s largest specimen.
It’s something of a letdown, then, to learn that butterflies sit firmly within the moth order, and are vastly outnumbered by their less brightly coloured biological relatives. “They are just day-flying moths,” says Picker. And, irrespective of their degree of beauty, they live on average for less than a month.
Deadly insects
Insects also present dangers to human health. Sitting on a tropical beach, for example, comes with an awful, albeit small risk — that of being targeted by an infected female phlebotomine sandfly, a vector for the parasite that causes leishmaniasis. The World Health Organisation (WHO) estimates a million people contract leishmaniasis each year, causing disfiguring skin lesions or ulcerated damage to the mucous membranes, and 70,000 deaths. It notes that the impact of climate change on rainfall and temperatures is widening the distribution of sandfly populations and concomitantly the geographic incidence of the disease, which is now also endemic to southern Europe and most of Africa — including neighbouring Namibia.
The sandfly is one of the Ceratopogonidae family of tiny, biting, bloodsucking midges. Their painful bites notwithstanding, they have cute colloquial names: miggies in SA, no-see-ums or punkies in the US.
A different insect, the tsetse fly, is the vector for the parasite that causes sleeping sickness, a risk for 65-million people in 37 sub-Saharan African countries. It’s fatal unless treated promptly; the incidence in underserved rural communities is difficult to ascertain, but the WHO estimates 50,000 people die annually.
But malaria is Africa’s biggest vector-borne disease, killing 593,000 people in 2021. Africa accounts for 96% of worldwide malaria deaths, with Nigeria, the DRC, Niger and Tanzania comprising over half of the global total.
There is a malaria risk in northeastern KwaZulu-Natal and parts of Mpumalanga and Limpopo. But, because only an infective female Anopheles mosquito transmits the parasite and, for many reasons, the Anopheles and the malarial pathogenic parasite aren’t both prevalent in the rest of SA, most of the country isn’t a malaria zone.
This ambit of insect behaviour and impact is enough to make anyone’s skin crawl, and it’s no surprise that medical entomology is a huge field in its own right.
What price?
In recent years, Burkina Faso’s Health Sciences Research Institute has been experimenting with gene drive nanotechnology aimed at making malaria-carrying mosquitoes sterile and dying out over subsequent generations. But other scientists point out that altering the genome of even one mosquito species may have unintended consequences. Essentially, it’s playing with fire because the future ecological effect cannot be ascertained.
And if medical doctors, religious leaders and ethicists view human or mammal gene editing as unnatural or even immoral, should that not also apply to the realms of the insect world? Ironically, as the world
makes progress to eliminate malaria — Cameroon recently became the first country to roll out vaccinations against the disease — Anopheles mosquitos are expanding their turf. Over the past century these insects have spread 4.7km polewards/year, and 6.5m higher annually in areas of altitude. Climate change is quickening this displacement.
Besides, there are other mosquitos. Alongside the Anopheles, avian malaria is vectored by different mosquito genera; so, puffins in north European zoos get it, as do many seabirds off SA’s west coast — and the Cape’s penguin colonies regularly suffer mortalities.
Social species dominate
It would seem impossible to estimate the number of ants on the planet. But biologists and scientists have somehow done this and concluded that their aggregate biomass exceeds that of all wild mammals and birds combined, and is about a fifth of that of humans. No wonder they play such a crucial role in ecosystems, often being more important in driving processes than the more conspicuous large mammals such as big cats and herbivores.
And they are one of the most advanced species of insects, largely because they are social. They form colonies that are sometimes enormous, such as those of the leafcutter ants. In 2012 a large abandoned ant nest in Brazil was painstakingly uncovered by scientists led by São Paulo State University professor Luiz Carlos Forti, revealing an underground megalopolis. Subterranean highways and secondary pathways lead with directional efficiency to queens’ large chambers, fungus gardens as a food source for ants’ larvae, and smaller chambers for food storage or waste.
The well-ventilated structure spans 50m² to a depth of 8m; it would appear to be designed by a great architectural mind, but the feat was the collective endeavour of the ant colony, as a superorganism, over perhaps decades. “The equivalent of constructing the Great Wall of China,” says the narrator of an astonishing video showing the scene. A University of Missouri anthropology professor summarises the discovery, in
the structure’s size and complexity, “blurs the lines between humans and animal”.
Yet this abandoned colony is neither unusual nor even the largest found. An estimated 307-million red wood ants lived in a supercolony of 45,000 nests spread over 16km in Hokkaido, Japan, discovered in the early 1970s. The Guinness World Record recognises the research of French, Danish and Swiss scientists whose findings were published in 2002 of a 6,000km stretch along southern Europe as being the biggest supercolony, comprising more than 1-million interlinked nests.
These and other discoveries prove that ants are architects and engineers, farmers and nurses, graziers and gourmands. They interact with almost all food chains, controlling or shaping ecosystems such that they are a keystone species, defined as one that has a disproportionately large effect on its natural environment. They display gallantry, leadership, self-sacrifice, and when they co-operate they form superpower units; they are also vicious and cruel, warmongers and slave-takers that predate on fellow social species like termites as well as each other. Just like humans, then.
Think, Am?
Of course, anthropomorphism is unhelpful to science in seeking an understanding of the insect world, and at its worst it misleads or hinders fuller understanding among the layman.
Still, some small anthropomorphism is at play when we admire or observe an insect (or, when we write about them). Questions arise. Just possibly, are they sentient? Do they experience their lives with any feeling?
If so, should this alter the way we interact with them? Absolutely, according to
Buddhism. Insects are sentient, and must not be killed.
But this religious edict has recently been supplemented with a surprising volume of cognitive science research supporting the position that they have the capacity for selfexperience as a requisite form of consciousness — basically, that they feel, whether we interpret that as joy, or suffering, or anything else.
Building on this, bioethicists and moral philosophers are thinking anew about issues such as the mass slaughter of large-scale pesticide use and agribusiness insect farms like InnovaFeed that kill trillions of insects every year for use in livestock and fish-farming feed products. Is this utilitarian attitude humane, even if the science is inconclusive?
Assigning human qualities to insects misses the point. Rather, we can assign insect attributes towards human innovation. This biomimicry has resulted in many astonishing technological inventions or product adaptations. The anatomy and functioning of grasshoppers’ legs have inspired robotic arms used in manufacturing process automation and developments in bionic legs for amputees. Observations of the dragonfly’s compound eye, comprising thousands of tiny lenses, has prompted the development of microlenses used in optical devices and a range of Industry 4.0 manufacturing applications. Weevils, among others, have inspired materials science design improvements.
The list goes on, though, contrary to expectation, insect flight and the composition of their wings is so complex that we are unable to apply it in aeroplane design. Bees and flies, for instance, beat their wings more than 1,000 times/second
— while all aeroplanes start with wing design that is fixed. Proof that nature, in this case insects, is an evolutionary miracle and is far more advanced than we are.
After all, they’ve been around for 480-million years. We think we’re smart, but as a 200,000year-old species we’re comparative newcomers and novices, still learning. So we should be humble enough to respect and appreciate, and to observe. After all, we must pay attention to tiny beings, believed the 19th-century Japanese art critic and scholar Okakura Kakuzo, lest “we ignore the large in ourselves”.
IT’S UNFORTUNATE THAT THE WILDLIFE WE CARE LEAST ABOUT PROVIDES US WITH THE MOST FUNCTIONAL VALUE
THEY DISPLAY GALLANTRY, LEADERSHIP, SELFSACRIFICE, AND … THEY FORM SUPERPOWER UNITS