What makes ants talented traffic controllers, even better than humans.
By Anne Kuckertz
It’s a common human experience, the sitting, the waiting, the cars honking around you. The wondering if your boss will be angry that you’re late or if your friends will wait for you to order dinner. It’s our shared mortal enemy: traffic. In 2020 Americans spent twenty-six hours stuck in traffic jams on average. So, what’s the solution to such a big problem? Perhaps it’s a tiny creature: an ant.
Ants are surprisingly good at traffic modulation. Hundreds of them somehow manage to simultaneously follow the same path efficiently and without big slowdowns. They don’t spend an obscene amount of time stuck in traffic, impatiently anticipating the minute they can get home and settle down to an episode of Netflix with a glass of wine. While humans experience a slow down in the flow of traffic once a road reaches forty percent capacity, ants can travel their trail systems up to an eighty percent capacity without issue.
Unlike us humans, whose sprawling concrete highways mar landscapes, ants’ “roads” are invisible. They’re built by scouts who set out from the nest in search of a food source. When they find a delicious fallen hot dog or forgotten ice cream cone, they head back to their colony, laying down a chemical trail as they return. It’s these pheromone-based paths that the rest of the ants follow, allowing their highway system to reshape itself as existing food sources are depleted, and new trails are laid by the constantly searching scout ants.
Once a path is set down, it’s flooded by ants traveling in both directions. One might think that this increased foot traffic would lead to ants bumping in to eachother, causing a melee of tangled antennae. And for some species of ants, it absolutely does. But for ants such as the black-backed meadow ant these ant-on-ant collisions may lead to increased efficiency. Making use of their robust exoskeletons, these black eyed speed machines actually increase their pace when more ants are on a path, leading to frequent crashes. But the industrious insects make use of these collisions to pass on information about the surrounding environment, leading to an overall faster flow of traffic. Imagine running in to a minivan and taking it as an opportunity to inform the driver that geese were crossing the road up ahead.
Not all ants utilize head-on collision messaging, in fact, the majority follow a traffic model somewhat similar to our own. Like our civil engineers, ants make use of some form of lane segregation, meaning that ants traveling in one direction stick to a similar path and those hurrying in another direction file through on another trail. For some species this means all outbound ants rush along two outer lanes and all inbound ants travel through a center path, flanked by their outbound coworkers. Other species send their outbound ants traveling along one side of a center lane and their inbound members on the other, leaving room in the center for a no-ant’s land where coming and going travelers make their way in a seemingly chaotic manner, somehow managing to avoid eachother. Of course, unlike concrete highways, these lanes are not absolutes. Lines blur together as needed, allowing for more efficient traffic management.
An eagle-eyed reader might have noticed that while what ants do to regulate foot traffic has been discussed, the how of it all is still unexplained. How do black backed meadow ants communicate during their collisions? How do other species coordinate where they draw their “lane lines?” “How has a creature whose mass is 0.000006% of our own solved such a ubiquitous human problem?” Currently, these mysteries are unsolved. There’s still much we don’t know about ant communication. Comparatively, we are most knowledgeable about ants’ chemical messages. We know that they use pheromones to lay down chemical trails. We know that ants use chemical signaling for a whole host of functions including deciphering the difference between ant stages of development, determining if an ant is deceased, and sending distress signals. Some studies have found that ants also use acoustic communication to broadcast messages like “Predator over here, come quick!” Scientists found that ants even shout out their social status, something along the lines of “Hey I’m your boss. Send help now!” This provides a possible explanation for the seemingly telepathic coordination of ant movement.
Although we have yet to decode what all these audio signals may mean, they could provide insight as to how ants are directing their traffic flow. This is information us humans could implement into our own transportation systems. We already benefit from reversible lanes where the direction of a lane can change as needed to best support traffic flow, a very ant-like method. But who knows what hidden secrets ants are whispering as they march in their disorderly ordered manner?
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