Two Brains are Better than One: Ant Colonies Optimize their Search for Food

The old adage "two brains are better than one" could not be more true for the seemingly unintelligent ant. Scientists have taken a closer look at these insects' movements and found that while individually they seem random, together they are organized in a way that allows the colony to efficiently search for food.

"Ants have a nest so they need something like a strategy to bring home the food they find," lead author Lixiang Li said in a press release. "We argue that this is a factor, largely underestimated so far, that actually determines their behavior."

In order to better understand the collective foraging behavior of ants, scientists piled everything they knew about the insect into equations and algorithms and fed this data into their computers. What they have come up with is that there are three stages to an ant's hunt for food: first, scout ants chaotically move around in circles, tiring themselves out so much that they return to the nest to eat and rest. Then, when one of these scouts is lucky enough to stumble onto some food in the vicinity, it takes a tiny piece of it back to the nest, leaving a trail of "breadcrumbs" so to speak that releases a scent-emanating substance called pheromones. Other ants follow this trail and bring more food home; yet because the trail is initially so weak, the ants will follow different trails. Over time, though, the trail will be optimized as more ants use the best trail and leave pheromones to mark it.

"While the single ant is certainly not smart, the collective acts in a way that I'm tempted to call intelligent," co-author Jürgen Kurths commented. "The principle of self-organization is known from for instance fish swarms, but it is the homing which makes the ants so interesting."

The mathematical model developed in studying the ants is applicable not only to very different kinds of animals which share their same problem-solving behavior, but also offers a new perspective on behavioral patterns of humans in areas that are as diverse as the evolution of web services.

The findings were published in the journal Proceedings of the National Academy of Sciences.