HONEY BEES 



becoming too dry to suit the grubs. It is sometimes also 

 used to dilute honey which has become too concentrated. 

 The hive is maintained at a very steady temperature, only 

 a little below that of our own bodies. The chief source of 

 heat is provided by the activities of the bees and their brood, 

 since the digestion of sugar automatically releases consider- 

 able energy. Workers regularly ventilate the hive by fan- 

 ning their wings at the entrance. This cools it to a consider- 

 able extent, even if water has not been brought in and 

 distributed, since the nectar loses much water as it is con- 

 centrated into honey. Ventilation serves to remove excess 

 water quite as much as to reduce the temperature. It is the 

 brood which is most sensitive to cooling and it always 

 occupies a roughly spherical space in the centre of the hive, 

 spreading through a number of the combs. 



It is clear that all these manifold activities demand a 

 considerable versatility in behaviour, and it is known, largely 

 from the experiments of Rosch with marked bees in a glass- 

 walled observation hive, that each worker tends to undertake 

 a number of successive activities according to its age. During 

 the active summer months the workers live five or six weeks 

 and the succession of duties is as follows: 



This schedule is not rigid. There is some overlap between 

 successive duties, and probably not all bees reach the same 

 physiological age in the same number of days. Still more 



in 



