By Christopher Cottrell, Special to CNN
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Berlin is abuzz with mechanical 'robot' bees
Berlin, Germany (CNN) --- Its brain is the size of a pinhead, but that doesn't stop the common honeybee from knowing basic geometry.
Widely regarded as one of the most intelligent insects on the planet, bees can use their mathematical prowess to communicate the exact location of nearby food to their hivemates via a technique dubbed the "bee dance."
It is the only known instance of symbolic communication in the animal kingdom and today a group of scientists in Germany is trying to build a robot that mimics it.
Dr. Raul Rojas, director of Berlin's Free University's Project RoboBee (yes, it's really called that), is trying to “hack the system” of the bees’ cognitive processes by constructing a mechanical bee capable of luring real ones out of the hive and leading them to food.
“When the bee dances, it waggles," Rojas said while trying to demonstrate the motion of a bee shaking its abdomen back and forth with his hands. “It also moves its wings, producing a sound, and makes a run in a certain direction before coming back and doing it all again.”
Rojas and his team are building on the legwork of Nobel laureate Karl von Frisch, an Austrian ethologist who spent decades researching insect communication. In the 1940s, von Frisch became the first person to decode the bee dance.
The crucial factors of the “bee dance” (see the video below; note: those aren't robots) are the angle at which the bee shimmies down the side of the hive and the dance’s duration, Rojas said. The duration is proportional to the distance at which food is located from the hive, while the angle tells the other bees which direction they have to fly in once they leave the hive.
So if a bee performs its dance at a 45-degree angle at 8 a.m., for example, when the sun is in the east, other bees know to fly roughly east-southeast.
“From a cognitive point of view, it's an amazing process," said Tim Landgraf, a graduate student who works with Rojas at the university's biorobotics lab. “The thing is, this super small bee has a brain the size of a pinhead.”
Rather than the furry, white mice that are the usual martyrs of scientific progress, Landgraf set his sights on bees after attending a lecture by Dr. Randolf Menzel, one of Germany's leading apian scholars.
Menzel "was still super curious and really seemed to like what he was doing," Landgraf said of the 72-year-old neurobiologist who is also involved in Project RoboBee. "So I asked him for a thesis and -- zap! -- I was working on detecting and tracking bee antennae in videos."
Using their own bee look-alike -- a small wad of foam wrapped in thin plastic and connected to a meter-high contraption of metal, plexiglass and computer wiring -- Landgraf and his colleagues are able to perform their own ”bee dance” via remote control.
"What we are trying to do with the robots is replicate the bee dance by making the same movements, the same sounds,” Rojas said, adding that they have even tried injecting sugarwater into the foam tip to trick the bees into thinking they smell nectar.
By sometimes omitting one of these factors -- be it wing movement, scent or heat -- the team comes closer to identifying the essential stimuli of the bee dance. The hard truth is that despite the progress they’ve made in identifying various components of the bees’ communication, they have yet to determine just how follower bees are able to decode the information in the dance.
Bee hives are dark inside, a fact that disqualifies any visual stimuli. So the dance, and all the encoded information it contains, must be communicated via stimuli that doesn’t rely on any visual signals.
Skeptics argue that bees don’t communicate direction or distance at all -- that their dance is simply a way to get the other bees excited and convince them to follow the dancing bee out of the hive. Others say it's the smell of nectar on the dancing bee's body that attracts the other bees.
Landgraf says these theories are likely incorrect because of the visible correlation between the direction in which the bee dances inside the hive relative to the location of food outside.
“I can’t think of a better way [to come up with an answer] than building a robot,” Rojas said.