We were asked if ants served a purpose. Now, that question tends to make us squirm as we’d rather no one looked too closely at what purpose human beings serve. But a little research turned up some interesting information about ants, their history, anatomy, community, and interactions with the natural environment. And, yes, they are very useful inhabitants of our planet.
A Place in History
Ants first scurried across the earth 140-160 million years ago in the Jurassic period. Their closest living relatives appear to be bees and wasps. Like bees, ants build nests, return to the nest after foraging, and many of them live in colonies. There are several wasp species that closely resemble ants. One is even known as the velvet ant.
Termites are only distantly related to ants. Their body structure is quite different, although both insects live communally. Termites are much more common in South America and Africa than they are in North America.
Ants were rare at first, but their numbers have grown as they’ve adapted to different locations. Some build their nests in decaying logs deep in the forest, while others nest in the soil or in tall trees. What they lack in number of species (approximately 8,800 worldwide with 580 found in North America), they make up for in sheer mass, which is greater than that of all wild birds and mammals combined.
Superorganisms
A single ant colony can contain millions of individual ants. Life is carefully structured with one or several queens responsible for reproduction, a few male drones whose only job is to mate with the queen, and lots and lots of female worker ants that are responsible for foraging for food, maintaining and protecting the nest, and looking after the young. Due to the size of the colonies, ants – like humans – build highways, set up public health units, and go to war.
Ant colonies are often referred to as superorganisms as, by working together, they achieve much more than they could individually. Their ability to share information is fundamental to their ability to work cooperatively. By secreting pheromones (scents), they share information about danger as well as promising sources of food. Their antennae serve to not only pick up scents from their surroundings but also give off scents that let other ants know whether they are friend or foe.
Insects spend up to 30% of their time grooming themselves to ensure they are in prime condition for picking up on sensory clues from their surroundings. For example, ants pull their antennae through a clamp-like structure on their front legs where bristles and combs trap and remove different sizes of particles.
Farmers & Herders
Many ants forage to find food, from fruits and grains to dead insects and mushrooms. Other ants have become farmers and herders.
Leaf-cutting ants carefully chop off chunks of leaves but don’t eat them. Instead, “They are compost – to nurture the gardens of delicious mycelium grown in the ants’ underground cities.” It’s a symbiotic relationship as the ants have done “such a good job of predigesting leaves that the fungus got rid of its cellulase enzymes. The ants, in turn, stopped making their own supply of the amino acid arginine as it is so plentiful in the fungal cells.” [The Hidden Kingdom of Fungi, Keith Seifert]
Other species of ants herd troupes of aphids in order to eat the sugary syrup they secrete. The ants herd the aphids around to the juiciest parts of plants, protect them from predators, and carry them into their nests at night and for winter.
Recyclers, Distributors, Warriors & Prey
Ants play an important role in creating healthy soil. They transport soil from deep below the surface up to ground level and create tunnels that aerate the soil and help water to penetrate below the surface. In addition, they transform leaves, dead wood, and other plant detritus into rich compost.
A few ant species, particularly in the deciduous forests of eastern North America, are key distributors of seeds. Seeds from plants such as the great white trillium have developed an oil-filled appendage that is prized by ants who drag the seeds away, eat the appendage, but leave the seed itself intact to germinate in a new location.
Ants in Oregon and Washington are fierce predators, destroying up to 85% of defoliating moth pupae.
African acacia ants defend acacia trees from grazing animals, receiving sap and accommodation in return. The ants will start patrolling a tree’s branches when vibrations alert them to the presence of a herbivore. They don’t react if the tree is moving in the wind.
Ants are small but numerous and are an important source of food for pileated woodpeckers and bears in British Columbia.
Idlers
Ants may appear to be always on the go and extremely industrious, but a recent study of worker ants in 5 forest ant colonies showed that half the ants spent their days doing nothing. Why this is the case remains a mystery. They could be guards, a back-up work squad, or providing food for tired workers.
Fun Stuff
In the game, The Ants: Underground Kingdom, you can build your own anthill, grow the colony, and defend it against enemies.
A rather neurotic ant tries to break from his totalitarian society while trying to win the affection of the princess he loves in the movie Antz.
In Tales from the Ant World, Edward O. Wilson recalls his lifetime with ants, from his first boyhood encounters in the woods of Alabama to perilous journeys into the Brazilian rainforest.
Ants: Little Creatures Who Run the World, an hour-long documentary hosted by Edward O. Wilson, explores the possibility that ants’ superpower is their ability to cooperate and work together unselfishly.
Photo credit: https://www.flickr.com/photos/apmckinlay/52698629515
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