Go to a park and look down at the ground. A colony of ants may be scurrying about, ferrying food here and there.
You are witnessing a small wonder of nature. The way the ants collaborate is a classic example of how animals maintain an efficient and effective network design. The ants get and move their food in an expeditious manner, minimizing energy use and maximizing calories.
“The striking thing about ants is that they build their networks without any central planning. Unlike human systems, there is no single ant having the big picture,” says Arianna Bottinelli, a math professor at the Uppsala University, in Finland. “Every single ant has just a bit of information about what is going on. Still, due to very frequent interactions, the whole colony together manages to build good networks.”
By “good,” Bottinelli means optimal for the ants’ environment, efficient, and robust. Studying meat ants for two years, Bottinelli has found the mathematical patterns that underlie the animals’ on-the-fly, decentralized network-making and has begun to think about the lessons could be applied to human planning. The work is published in the the Royal Society journal Interface.
The ants have a simple rule: “connect to the closest node,” which they do again and again. (Meanwhile, slime mold has the same network properties as the Tokyo rail system.) The ants join up with one another in an apparently random but wholly dynamic way. “We have learned that a simple rule iterated several times during the growth of a network balances efficiency and cost fairly well, and that can be also made robust,” Bottinelli says.
These same skills could be useful for building out efficient electric grids or water networks, perhaps connecting a new suburb to the closest existing one.