Ants have a unique processing center in the brain that is not found in other social animals, say scientists.
It sheds fresh light on how they provide food, shelter and defense for an entire colony.
The ‘superpower’ enables a lone scout to invade your home – before summoning its nest mates inside.
Traps catch only a few – but soon, the others have mysteriously disappeared.
The phenomenon has even stumped entomologists until now.
“Humans aren’t the only animals with complex societies and communication systems,” said the lead author Dr. Taylor Hart, of The Rockefeller University New York.
“Over the course of evolution, ants have evolved extremely complex olfactory systems compared to other insects, which allows them to communicate using many different types of pheromones that can mean different things.”
They detect the chemicals with their antennae. Ants first appeared up to 168 million years ago – when dinosaurs ruled the Earth. There are now more than 12,000 species.
Ants outnumber humans by a million to one. The findings shed fresh light on their success – showing how scents they emit activate a specific part of the brain that changes the behavior of an entire nest.
The communication stations can interpret alarm pheromones, or “danger signals,” from peers.
It’s believed to be even more advanced than that of honeybees, which rely on many different parts of their brain to coordinate in response to a single pheromone.
“There seems to be a sensory hub in the ant brain that all the panic-inducing alarm pheromones feed into,” said the corresponding author Dr. Daniel Kronauer, also from Rockefeller.
The U.S. team used an engineered protein called GCaMP to scan the brain activity of clonal raider ants that were exposed to danger signals.
The gene works by attaching itself to calcium ions, which flare up with brain activity, and the resulting fluorescent chemical compound can be scanned on adapted high-resolution microscopes.
Only a small section of the ants’ brains lit up in response, but they still showed immediate and complex behaviors in response.
They involved ‘panic’ actions such as fleeing, evacuating the nest and transporting offspring from the nest toward a safer location.
Species of ants with different colony sizes also use different pheromones to communicate a variety of messages.
Dr. Hart said: “We think that in the wild, clonal raider ants usually have a colony size of just tens to hundreds of individuals, which is pretty small as far as ant colonies go.
“Frequently, these small colonies tend to have panic responses as their alarm behavior because their main goal is to get away and survive. They can’t risk a lot of individuals.
“Army ants, the cousins of the clonal raider ants, have massive colonies—hundreds of thousands or millions of individuals—and they can be much more aggressive.”
Regardless of the species, ants within a colony divide themselves by caste and role, and ants within different castes and roles have slightly different anatomy.
The researchers chose clonal raider ants because they are easy to control – and only female workers to ensure consistency and therefore make it easier to observe widespread patterns.
Once researchers have a clearer understanding of the neural differences between castes, sexes, and roles, they may better be able to comprehend exactly how different ant brains process the same signals.
“We can start to look at how these sensory representations are similar or different between ants,” said Dr. Hart.
Dr. Kronauer added: “We’re looking at the division of labor. Why do individuals that are genetically the same assume different tasks in the colony? How does this division of labor work?”
The study was published in the journal Cell.
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