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Researchers use tiny robots to test ant behavior theory

Fri., March 29, 2013

LOS ANGELES – Which is smarter: a swarm of brainless mini-robots with clockwork guts, or a colony of ravenous, half-blind Argentine ants?

If you answered mindless robots, you’re right – but just barely.

Researchers studying the problem-solving abilities of foraging ants enlisted the aid of 10 sugar-cube-sized robots to determine whether the real-life insects had to put any thought into deciding which direction they should go when they came to a fork in the road or an obstacle in their path. The answer to that question is important for the understanding of how large communities of organisms interact and coordinate their behavior.

The Argentine ant was selected for the study because it’s among the world’s most successful invasive species. When it gains a foothold in new lands, such as California, Florida, southern Europe, Australia and Southeast Asia, it out-competes local ants and can sever links in the larger food chain.

Scientists at NJIT and the Research Center on Animal Cognition, in Toulouse, France, hypothesized that the ants’ foraging success was due to instinctive behaviors, and not the result of calculations made by individual ants. Researchers tested their hunch by setting up a competition between real ants and a squad of micro-robots designed at EPFL, a technical university in Lausanne, Switzerland.

In the live-animal experiment, a colony of 500 worker ants was starved for a couple days and then set free in a maze carved into a plastic board. Researchers placed a cotton ball soaked in a sugar solution at the opposite end of the maze and observed as the ants went into a frenzied search for food before returning to their nest.

The robot experiment took a lot longer to set up and conduct.

Each robot comes equipped with two Swatch watch motors and four tiny wheels. The robo-ants communicate with light instead of pheromones.

The electronic critters were programmed to move randomly, but in the same general direction – just like real ants.

The robot ants were released into a cardboard maze with infrared light beacons to simulate their nest and their food source. As they wheeled down passageways, an overhead projector beamed blue circles onto the pathway behind them, as if they had left a pheromone marker for their buddy robots behind them. When the robots encountered an intersection, they were programmed to take the route that deviated least from their general direction of travel. However, if they encountered a blue circle of light, they followed that instead. After running the contest many times, their rates of success and overall routes were very similar, although the robots tended to use shorter routes, the researchers found. Also, when the robots bumbled into closed loops, they were more likely to break free.

The research team concluded that “a complex cognitive process is not necessary to explain the ants’ behavior.”


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