Ants Form 'Superorganism' When Threatened
Ants are so incredibly coordinated that many of them together behave as one.
Ants are so in tune with each other that they function as a single superorganism when under threat, new research finds.
The discovery, reported in the journal PLOS ONE, adds to the growing evidence that ultra social beings, such as ants, act more as one living entity than as individuals, at least under certain circumstances.
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The resulting superorganism is "much greater than the sum of their individual parts," wrote lead author Thomas O'Shea-Weller of the University of Bristol and colleagues Ana Sendova-Franks and Nigel Franks.
Using a fine-tipped brush, the researchers simulated different predator attacks on 30 migrating ant colonies. To do so, they removed ants that were serving as scouts on the colony periphery. Then, separately, they removed worker ants from the center of the nest.
The scientists found that when scouts were moved from the periphery, the foraging "arms" of the colony retracted back into the nest, with the individuals appearing to move as one, sort of like a marching band in formation seen from above.
Conversely, when the worker ants were removed from the center of the nest, the whole colony fled as one and sought refuge in a new location.
The authors draw parallels with the nervous systems of individual humans and other solo organisms. The first ant disturbance, and subsequent reaction, was likened to a person burning his or her hand on a stove. The second, they say, was "more of a house on fire scare."
As O'Shea-Wheller said in a press release, "Ants react very differently, and in a coordinated fashion, to perceived predator attacks depending on their location."
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He added, "Just as we may respond to cell damage via pain, ant colonies respond to the loss of individuals via group awareness and reaction."
The term "superorganism" was coined way back in 1789 by scientist James Hutton, who is often referred to as the "Father of Geology." It technically refers to "a collection of agents which can act in concert to produce phenomena governed by the collective."
A question then to ask is: What is to be considered the individual? Consider that earlier research found that 90 percent of the cells within our bodies are not ours, but are instead microbes.
Superorganisms may be far more common than we thought.
Close-up of an ant colony in an artificial nest.
Real-life ants have powers beyond Hank Pym’s super-strength. They also float on water, build massive skyscrapers, dig crazy underground tunnels and will attack much larger creatures in huge numbers using massive jaws. With a nod to Marvel’s new film “Ant-Man,” here’s a look at some unusual abilities of our formic friends.
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Ants are nature’s excavators. They move pebbles, rocks and bits of soil in all kinds of conditions to help the colony survive, often one holding onto another like a tiny ant jackhammers. “If you put a fire ant in soil, it will begin to dig,” said Dan Goldman, physics professor at Georgia Tech who studies how animals build and move. “They do it over and over in any soil. They use their mandibles, limbs and antenna to shape and create these snowballs and move them thousands of body lengths onto the surface to create the mound.”
There is no fiercer predator than tens of thousands of army ants pouring across the jungle floor in search of hapless prey. These ants are among the largest species, and are either blind or have almost no eyesight. Yet they can still scour the forest floor for insects, small birds or, on occasion, unwary villagers. “They are the pack hunters of the tropics,” says Sean Brady, chair of the department of entomology at the Smithsonian Institution’s National Museum of Natural History in Washington.
Ants build the equivalent of human skyscrapers with no blueprints and nobody telling them what to do. “Every construction worker is lifting their own stuff, all milling around, banging around in the complete dark relentlessly day in and day out,” said Georgia Tech’s Goldman.
Ants don’t vocalize, but they still talk amongst themselves, using their antennae. They also secrete chemicals called pheromones to either warn the colony of an attack, or to lay a trail to food for others to follow. “It’s all chemical and tactical,” says the Smithsonian’s Brady. “What they are saying to each other and how they figure out where to go, we don’t understand that yet.”
Here’s a video of two ants communicating
via antennae, a method biologists call “stimergy.”
When Hurricane Katrina swamped much of the Gulf Coast, local residents not only had to worry about finding clean water or shelter, they also had to avoid bumping into huge floating mats of living fire ants.
Ants have big chompers. The bullet ant is so named because its bite feels like getting shot. The trap-jaw ant has such a powerful bite that researchers have watched them get pushed backward when chomping onto a hard surface, such as a wall or glass.
Some ants have evolved a cooperative existence with other insects, such as aphids or scales. The ants watch over these plant-sucking critters, keeping predators away, while the aphids provide ants with a sweet liquid called honeydew. Beats getting in fights all the time.
When ants have to cross an obstacle, they build a living bridge, gripping each other to let the others crawl across. “A bridge may be several ant lengths long and they will be that way for hours,” said Michael Goodisman, associate professor of biology at Georgia Tech who also worked as a consultant on the new “Ant-Man” film. “Imagine a human chain would last a minute. They can hold onto each other and support many ants themselves.”
Even though each ant has its own role -- worker, drone, soldier and queen, they behave more like one big insect with the goal of keeping the colony alive, well-fed and reproducing. “Ants have the most sophisticated social characteristic of any animals,” Goodisman said. “They need each other. They cannot survive on their own. It has to be associated with a colony to transfer its fitness to future generations. Ant colonies act as super-organisms.” This hive behavior was exploited in H.G. Wells' "Empire of the Ant," made into
Most male ants are pretty useless -- they exist to mate (then quickly die) and take part in few defensive or care-taking roles, experts say. But male army ants do get to fly around. In fact, they are so big that call them “sausage flies.”