Leaving awake of dishes in the sink one Saturday night, we settled in to watch Casablanca. Bogart glowered and Bergman glowed, but meanwhile, in the kitchen, a scout from a nearby ant colony had found a bowl of icing-sugared popcorn. It returned to the nest with the news, dragging its abdomen to leave a chemical trail like a line of Post-it notes. By the time we emerged from 1940 Morocco, a bristling black ribbon of at least a thousand ants was running in geometric precision through the open window and across the wall.
I shrieked and started manically wiping them off. The cloth was black with stinking corpses, even as the ants poured through the window faster than ever. (I was unaware that a squashed ant emits an alarm pheromone, attracting reinforcements from the colony.)
I’ve since discovered a gentler approach to ant control, advocated by the world’s leading authority on the creatures, Harvard professor emeritus Edward O. Wilson.
“The question I’m most often asked about ants,” he writes in his book In Search of Nature, “is, ‘What do I do about the ones in my kitchen?’ And my answer is always the same: ‘Be careful of where you step: Be careful of little lives. Feed them crumbs of coffeecake. They also like bits of tuna and whipped cream’.”
Wilson is convinced that we have a lot to learn from ants. For one thing, ants have been around for at least 100 million years. And although we’re seldom aware of them, there are about a million billion ants, making them one of Earth’s dominant animals. They’ve achieved this feat of world domination without voices or language, and yet they’re incredibly skilled communicators.
“Buy a magnifying glass and watch ants closely,” Wilson suggests, “and you will be as close as any person may ever come to seeing life as it might evolve on another planet!”
Wilson is speaking of ant societies, but even in the morphology of ants there is something that fits our notion of alien life forms. With their inscrutable, mask like faces, any of the world’s 12,000 or so described species would look at home on the set of a George Lucas movie, but ants are as physically varied as the countless ecological niches to which they have adapted. Some look meek and deferential, others wizened, some cheeky and bird-like, others hulking and muscular.
As if waiting for messages to arrive from a distant mothership, ants appear to lean forward intently, hunched over slim, agile legs that carry them at a speed of nearly 800 times their own body length per minute. Their purposeful, frantic movements have an intensity that is hard to equate with anything we experience as humans. They seem controlled by a force outside themselves, and in a way they are.
Unburdened by the constant jostle between morality and self-interest that is part of the human ego, ants need only respond robotically to the chemical messages produced by the members of their colony—together, we thrive.
Messages pour forth from several parts of an ant’s body—Dufour’s glands, poison glands, and glands on the hindgut, rectum and hind tibia. The alarm pheromone, with which ants warn the colony of danger even as they are dying, is located in the mandibles; when capturing prey, ants call for help using short-range recruitment signals from their sternal gland.
These chemical messages, known as pheromones, are received by the forward-pointing, elbowed antennae, which act much like a nose. When ants meet, they run antennae over one another, ‘sniffing’ for smells and tastes that function in the same way as facial expressions, words and tone of voice do for us.
If the ant smells of their colony, they know it to be a friend; if it smells unfamiliar, they are wary of a potential foe. Among members of a colony, more complex chemical profiles communicate information about where an ant has been foraging and how desirable the food source was. Ants swap roles within the colony according to the chemical information emitted by their bodies—researchers found that ants that were allowed to succeed in foraging efforts continued to work as foragers, while another group that failed soon elected to work in the colony’s nursery.
Pheromones are also passed throughout the colony by trophallaxis—feeding from mouth-to-mouth—so that whatever is eaten by one ant is eventually distributed throughout the stomachs of every ant in the colony. Wilson emphasises the significance of food sharing as a more important indicator of social advancement than leadership or dominance. He points out that sharing of food is a central ritual in almost all human cultures and suggests that it is also at the heart of an ant colony’s ability to act as a superorganism—a community of organisms with the collective intelligence that makes them more capable than solitary insects.
“When everyone has roughly the same stomach content, individual decisions become similar, and a more harmonious form of mass action is possible,” he writes.
The idea of the superorganism, whereby an ant colony thinks and acts as if it were a living entity, has fascinated scientists and mathematicians. The system works as a sort of chemical democracy—the votes the result of many small decisions and interactions of its members.
One ant puts forward a motion by leaving a pheromone message suggesting others might like to investigate it too. If the motion (for example, an appetising food source) is found to be true by subsequent ants that follow the scout’s trail, the pheromone message grows stronger, and stronger still, until the food source is exhausted or the arrival of predators makes foraging unsafe.
But ants also display effective communal behaviour in other ways. The colony ensures high levels of nurture: nurse-worker ants are fastidiously attentive to the eggs, larvae and pupae that they are responsible for—licking them to protect from bacteria in the soil, and moving them from chamber to chamber at different times of the day to ensure they are kept at optimum temperature. Ants rush to sacrifice their own lives in defence of the colony as a whole. There is even evidence that they are tender with one another—when a colony shifts to a new nest site, an ant that is reluctant to make the long journey is prodded gently by a stronger ant, and if it still proves reluctant, it is picked up and carried.
In Darwinian terms, altruism and cooperation are the means by which ants have survived so long, but it’s also easy to draw parallels between our societies.
Ants consistently practise what humans know at our best moments: that there is no lasting happiness for any one of us until there is happiness for all of us. Or, in Wilson’s words, “Karl Marx was right, socialism works, it’s just that he had the wrong species.”
This is not to suggest that an ant colony is a kind of subterranean hippy commune. Ants are bellicose creatures—“the most warlike of all known animal groups, solitary or social,” according to Wilson—as well as fierce predators of other small animals. ‘Scout’ worker ants keep a close eye on the health and status of nearby colonies, ready to sniff out weakness. Medieval-style tournaments, which involve a stiff-legged dance equivalent to the posturing of knights on horses, advertise a colony’s willingness to scrap.
When colonies decline, as they inevitably do in the course of a natural life cycle, they are quickly raided by a watchful neighbour. In ant wars, those ants that aren’t killed in combat are often taken as slaves, brainwashed with a new chemical identity and added to the dominating colony’s workforce.
Unlike the 95 per cent of insects that are solitary, ants—along with bees, termites and wasps—have figured out that doing everything yourself makes for inefficiency and risk. As every human parent knows, tasks such as child-rearing impede one’s progress in other chores; foraging for laundry powder and baked beans, for example, becomes almost unbearably inefficient when carried out in conjunction with the task of tending to small children. Ants cut down on this multitude of inefficiencies by delegating tasks very specifically within their colonies. The most dramatic of these delegations is reproduction.
One unenviable female—although she bears the glorious title of queen—is entirely responsible for laying the colony’s eggs, remaining deep in the bowels of the nest and laying an egg as often as every 15 minutes for as long as she lives, which could be up to 20 years. Worker and soldier ants divide up the tasks required to support the reproductive efforts of their queen between them, bringing food into the colony, taking care of the young and making sure the nest is safe. These ants are all females that are electively sterile, suppressing their reproductive capabilities in favour of supporting the queen.
A small number of males are present in the colony, but they’re kept firmly in their place, the nursery, until they’re physically mature. At this point, these pampered young males, known as drones, are pushed out of the nest with strict genetic instructions to go forth and multiply. Physically different from their sisters, the features they will need most are emphasised—they have wings, big eyes, enormous genitalia and a tiny brain hard-wired to fly away, find a willing female, pass on the colony’s precious genes, and die.
The female larvae that are designated to reproduce—called virgin queens—are also nurtured in the nursery and sent forth in mating season. The journey before the virgin queen is rather more epic than that of her semen-loaded brothers. Her nuptial flight is a kind of prima-ballerina solo, an event of brief and dazzling importance, when all the hopes of the colony are projected onto that one large, potentate figure.
In the warm breath of a summer morning, she breaks free of the maternal hold of the queen mother, bolstered by the nurture of sisters and borne on wings which she will use for a single grand performance. In the air, she is mated by one or several males, before she flies as far as she can from her home nest and settles to the ground. Not to die, however: a lifetime’s supply of sperm is brewing inside her. Snapping off her wings, which will henceforth be useless in her subterranean life, she selects a nest site and starts to dig, all the while beset by the likelihood that she’ll be picked off by any one of a range of predators. When there is enough of a chamber to offer rudimentary protection, she starts to lay newly fertilised eggs.
At this point, a new danger sets in. The soil around her teems with fungi and bacteria that, given a second’s inattention, would colonise the newly laid eggs and destroy them. With saliva full of antibiotic properties, the queen licks the eggs constantly to prevent this. Larvae hatch out of the eggs and she feeds them with fatty reserves regurgitated from her own body before they undergo several moults and pupate. When they finally step out as fully formed adult ants, the queen has some help at last. Her daughters are the first workers of the newly formed colony. They fall instinctively to their tasks: some leave the nest to forage for food, others stay near the queen to clean the nest and support her while she regains her strength and continues to lay eggs.
Once established, ant colonies can grow quickly, benefiting all around them.
Ants play a key role in the pollination of low-growing flowers, and are hardworking dispersers of seed. They are critical to soil health—more so even than earthworms—as their galleried cities provide permanent plumbing to aerate the soil. Through their tireless retrieval of plant and animal matter from the world above, ants feed their hungry larvae and inadvertently improve the nutrient levels of topsoil. They are also vitally important to the control of other insects, keeping potential pest species in check. Their small size does not matter in this instance; they work in teams to haul whatever nutrients they can scavenge or kill—languishing caterpillars, cicada legs, pieces of discarded exoskeleton, Marmite sandwiches.
If we can learn anything from ants, it might be some lessons in longevity and community. Faced with a biosphere out of balance and a human population living beyond its resources, we might be well served to pay heed to these quietly powerful critters which put their civilisation before themselves, lest they, as Wilson suspects, “outlast our own fractious and impatient species”.