To explore how groups of cockroaches make collective decisions, scientists have created a robotic cockroach that the real insects accept as one of their own.
The robot doesn’t look anything like a cockroach to human eyes.
“It looks like an electronic matchbox,” said Jose Halloy, a researcher at the Universite Libre de Bruxelles in Belgium. But that doesn’t matter, he says, “because in fact it has to look like a cockroach from a cockroach perspective.”
Basically, it has to smell like a cockroach. The scientists coat the boxy robots with a chemical, a cockroach smell, so the real roaches won’t run away.
“The cockroaches are not at all stressed by the robots because they are perceived as cockroaches,” Halloy said. “So the cockroach is just accepting that kind of strange buddy. And that’s the start of the game.”
The game was to see if researchers could use this robot to figure out how roaches make group decisions. “Cockroaches are gregarious insects, so they live in groups,” Halloy said. They don’t live in complex societies like bees or ants, he said, but roaches do make choices.
For example, they like to rest together. When scientists put cockroaches in a habitat that has two identical little shelters — shadowed places where they can hang out — the roaches will “all gather together in the same shadow, below the same shelter,” Halloy said. “So there is a mechanism that makes the system choose one of the shelters.”
Halloy and his colleagues suspected that a group decision emerges because every individual follows these simple rules: Wander around randomly, but spend more time in a place if you sense that it is (A) dark and (B) has other cockroaches.
So the researchers made sure their robotic cockroach could follow those rules. The robots had wheels, plus a light sensor and an infrared sensor to detect nearby roaches.
When they put these robots in with the living roaches, they all began to interact. Before long, the robots and cockroaches were huddled together under the same roof. “The robots and the cockroaches behave as a group,” Halloy said.
[Read On: npr]