advertisement
On MovieTome: Captain America in IRON MAN?
Find Articles in:
all
Business
Reference
Technology
News
Sports
Health
Autos
Arts
Home & Garden
advertisement

Content provided in partnership with
Thomson / Gale

Quantum honeybees - research on honeybee behavior

Discover,  Nov, 1997  by Adam Frank

How could bees of little brain come up with anything as complex as a dance language? The answer could lie not in biology but in six-dimensional math and the bizarre world of quantum mechanics.

Honeybees don't have much in the way of brains. Their inch-long bodies hold at most a few million neurons. Yet with such meager mental machinery honeybees sustain one of the most intricate and explicit languages in the animal kingdom. In the darkness of the hive, bees manage to communicate the precise direction and distance of a newfound food source, and they do it all in the choreography of a dance. Scientists have known of the bee's dance language for more than 70 years, and they have assembled a remarkably complete dictionary of its terms, but one fundamental question has stubbornly remained unanswered: How do they do it? How do these simple animals encode so much detailed information in such a varied language? Honeybees may not have much brain, by they do have a secret.

Most Popular Articles in Reference
The importance of understanding organizational culture
Credit card attitudes and behaviors of college students
What factors attract foreign direct investment?
Libraries Need Relationship Marketing - mutual interest marketing concept, ...
How to set performance goals: employee reviews are more than annual critiques
More »
advertisement

This secret has vexed Barbara Shipman, a mathematician at the University of Rochester, ever since she was a child. "I grew up thinking about bees," she says. "My dad worked for the Department of Agriculture as a bee researcher. My brothers and I would stop at his office, and sometimes he would how show us the bees. I remember my father telling me about the honeybee's dance when I was about nine years old. And in high school I wrote a paper on the medicinal benefits of honey." Her father kept his books on honeybees on a shelf in her room. "I'm not sure why," she says. "It may have just been a convenient space. I remember looking at a lot of these books, especially the one by Karl von Frisch."

Von Frisch's Dance Language and Orientation of Bees was some four decades in the making. By the time his papers on the bee dance were collected and published in 1965, there was scarcely an entomologist in the world who hadn't been both intrigued and frustrated by his findings. Intrigued because the phenomenon Von Frisch described was so startlingly complex; frustrated because no one had a clue as to how bees managed the trick. Von Frisch had watched bees dancing on the vertical face of the honeycomb, analyzed the choreographic syntax, and articulated a vocabulary. When a bee finds a source of food, he realized, it returns to the hive and communicates the distance and direction of the food to the other worker bees, called recruits. On the honeycomb which Von Frisch referred to as the dance floor, the bee performs a "waggle dance," which in outline looks something like a coffee bean--two rounded arcs bisected by a central line. The bee starts by making a short straight run, waggling side to side and buzzing as it goes. Then it turns left (or right) and walks in a semicircle back to the starting point. The bee then repeats the short run down the middle, makes a semicircle to the opposite side, and returns once again to the starting point.

It is easy to see why this beautiful and mysterious phenomenon captured Shipman's young and mathematically inclined imagination. The bee's finely tuned choreography is a virtuoso performance of biologic information processing. The central "waggling" part of the dance is the most important. To convey the direction of a food source, the bee varies the angle the waggling run makes with an imaginary line running straight up and down. One of Von Frisch's most amazing discoveries involves this angle. If you draw a line connecting the beehive and the food source, and another line connecting the hive and the spot on the horizon just beneath the sun, the angle formed by the two lines is the same as the angle of the waggling run to the imaginary vertical line. The bees, it appears, are able to triangulate as well as a civil engineer.

Direction alone is not enough, of course--the bees must also tell their hive mates how far to go to get to the food. "The shape or geometry of the dance changes as the distance to the food source changes," Shipman explains. Move a pollen source closer to the hive and the coffee-bean shape of the waggle dance splits down the middle. "The dancer will perform two alternating waggling runs symmetric about, but diverging from, the center line. The closer the food source is to the hive, the greater the divergence between the two waggling runs."

If that sounds almost straightforward, what happens next certainly doesn't. Move the food source closer than some critical distance and the dance changes dramatically: the bee stops doing the waggle dance and switches into the "round dance." It runs in a small circle, reversing and going in the opposite direction after one or two turns or sometimes after only half a turn. There are a number of variations between species.

Von Frisch's work on the bee dance is impressive, but it is largely descriptive. He never explained why the bees use this peculiar vocabulary and not some other. Nor did he (or could he) explain how small-brained bees manage to encode so much information. "The dance of the honeybee is special among animal communication systems," says Shipman. "It conveys concise, quantitative information in an abstract, symbolic way. You have to wonder what makes the dance happen. Bees don't have enough intelligence to know what they are doing. How do they know the dance in the first place? Calling it instinct or some other word just substitutes one mystery for another."