PHYSIOLOGY AND BEHAVIOR Of THE ARTHROPODA 



349 



while the excited bees fly out of the hive and circle the neighborhood 

 until they locate the same scent. When they return they, too, will round- 

 dance. All dancing bees repeat the j^rocess only a few times before re- 

 turning to the source for another load. As long as the source holds out, 

 the returning bees dance. When the supply dwindles and becomes 

 harder to get the bees will no longer dance, but they will continue to 

 return to the source until nothing at all is left. 



This procedure is not adequate, however, to locate sources that 

 are farther away. A bee returning from a distance performs a wagging 

 dance (Fig. 17.21). She walks in a semicircle, then rushes straight back 

 to the starting point, walks around the other way, rushes, and repeats. 

 On the straight rush she waggles the abdomen vigorously. Neighboring 

 foragers become excited by this dance also, following closely with their 

 antennae. An astonishing amount of information is thus transmitted. 

 The followers not only become excited and pick up the scent of the 

 source, but they also learn how far away it is and in what direction! 



Distance is indicated by the tempo of the dance, by the speed with 

 which the cycle is completed (the closer the source, the more rapid the 

 dance (Fig. 17.22)). For long distances the rate may be as slow as four 

 cycles per minute. Von Frisch, who worked out this interpretation of 

 bee language, found that most of the "listening" bees learned the dis- 

 tance to within 25 per cent. Detailed studies, with winds in various 

 directions, showed that distance was actually given as the amount of 

 time required to fly to the source. Most remarkable is that bees flying 

 home with the wind make a correction for this and signal a distance 

 appropriate for the time it w-ould take to get there against the wind. 



The direction to the source is indicated by the direction of the 

 straight rush. This is the most ingenious part of the vocabulary since it 

 necessarily involves a translation of marks. Outside the hive the bee 

 uses the sun as a landmark. Inside, on the vertical surfaces of the 



10 



8 



VI 



C 

 



^ 7 

 \n 



in 6 



m 

 C 



o 



;-. 



E 



Kilometers between source a.-ndhive 



Figure 17.22. The relation between the distance of the food source from the hive 

 and the number of straight rushes per fifteen seconds in the wagging dance. As the dis- 

 tance becomes shorter the dance merges into the round-dance. (After von Frisch.) 



