Telling the Bees

How doth the little busy bee

Improve each shining hour . . .

In a new book, Bees (Cornell University Press; $3), Professor Karl von Frisch of the University of Munich sets out to improve on Poet Isaac Watts's description.

In each hive commune, says Dr. von Frisch, a few bees are honey scouts. They patrol the neighborhood looking for new-opened flowers. Their big, compound eyes see well, but they do not see what human eyes see. Blind to red, a bee sees a clear red flower as grey. But at the other end of its color spectrum, a bee can see ultraviolet, to which human eyes are blind.

The scout bee cannot smell flowers at any great distance; its odor perception is about as sharp as a man's. But when it alights on a flower to which it has been attracted by sight, it is so close to the flower's scent glands that very faint odors are perceptible. Most flowers have "scent spots," which the bee feels out with the organs of smell on its antennae. The scent spots lead the scout to the cups where the nectar lies.

Glad Tidings. There the bee unlimbers its sense of taste, which is specialized to test the quality of nectar. A sugar content of 5% does not interest a bee; such nectar would spoil in the hive before it could be concentrated into long-keeping honey. A 20% sugar content is satisfactory, and 40% makes the bee wildly enthusiastic. It sucks up some nectar and marks the flower with its own scent from a gland on its abdomen. Having thus staked a claim, it heads back to the hive to spread the glad news.

How does it tell and what does it tell? By elaborate experiments over many years, Dr. von Frisch deciphered some phases of bee language. A scout bee, he says, can tell its fellows what kind of flower contains the honey-trove, in what direction it lies, and how far away it is.

When the scout bee enters the hive, he says, it climbs to a section of comb and starts a stylized dance. Other bees gather around, caressing the scout with their touch-and-smell antennae. The scout bee's odor, picked up from the flower it has robbed, tells them what sort of flower they should look for.

The dance has meaning, too. If the scout bee dances on the same spot, whirling first to the right, then to the left, it is telling the other bees that a honey source lies close to the hive. As they swarm out eagerly to look for it, the scout bee goes to another comb to tell the news to still more of its hive-mates.

Wags for Distance. To tell about sources 100 meters or more from the hive, the scout bee does another dance. It wags its abdomen from side to side, runs forward a few steps, turns around, runs forward and wags again. The more rapid the turning and wagging, the closer the honey lies. Dr. von Frisch fed scout bees at varied distances from the hive and timed the tempo of their dancing. He found that when they made nine or ten complete dance cycles in 15 seconds, it meant that the honey flowers were 100 meters away. Seven cycles meant 200 meters; 4 1/2 cycles meant 1,000 meters. The matching bees time the dance, as Dr. von Frisch did.

The scout bee also points out the direction. On its way back from the honey-find, it has noted (probably by means of apparatus built into its compound eyes) the direction in which the light of the sky is polarized.* This tells the position of the sun even when the sun is not directly visible. When the scout bee steps forward during its wagging dance, the direction in which it steps tells the other bees where to fly. If it moves vertically upward on the comb face they know they should fly toward the sun, guided by polarized sky light. A run 60DEG away from vertical tells them to fly 60DEG to the left of the sun. Careful experiments show, says Dr. von Frisch, that bees briefed by the honey dance seldom deviate more than 15DEG from the correct direction.

*Direct sunlight vibrates transversely in all directions equally. Sky light scattered by atmospheric particles vibrates more in some directions than in others.

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