SOLITARY AND SOCIAL BEES 



Later batches of eggs are laid in little pockets attached 

 to the side of the cocoons. Mr. and Mrs. M. V. Brian, 

 working at Glasgow, have recently shown that there is a 

 tendency for the number of eggs in the group to be propor- 

 tional to the number of cocoons in the clump on which they 

 are laid. Taking the average of cocoon groups of different 

 sizes, there were about three eggs for each cocoon, with 

 six to sixteen eggs in a batch. This seems to be a form of 

 family planning which ensures that there shall be no more 

 brood to look after than there will be nurses to care for 

 it. 



At this stage, the brood soon becomes too large to be 

 incubated by the queen, and the groups of larvae or cocoons 

 no longer form a groove but are convex on top. The develop- 

 ing brood produces enough heat from the digestion of its 

 rich food to keep the whole nest at a sufficiently high tem- 

 perature. 



At the beginning of the eighteenth century, a Dutch 

 naturalist, Goedart, first propagated the curious myth of the 

 " trumpeter " humble bee. He observed that a bee often 

 rests on the top of the nest, fanning with its wings and making 

 a loud hum. This often occurred in the early morning when 

 the sun's rays first strike the nest, and Goedart thought that 

 the hum of the vibrating wings was a call to start the morn- 

 ing's work. During the last two hundred and fifty years 

 naturalists have argued whether the " trumpeter " really 

 existed, and if so what were his functions. The Austrian 

 entomologist, Hoffer, finally showed that trumpeting really 

 occurred by observing a colony in a nest-box on his window- 

 sill. Eventually, Plath in America showed that it happened 

 especially when the nest was exposed to the sun, and that 

 this could be checked by moving the nesting-box to different 

 positions. Fanning sometimes occurs also in the evenings 



87 



