THE SOCIAL INSECTS 



may be severe competition for nests, and one or even more 

 dead queens may be found at the entrance to the nest, killed 

 by the rightful owner in defence of her property. Secondly, 

 there is a limit to the number of nests which can exist on an 

 area, and this may be very important in the production of 

 such crops as red clover-seed, since humble bees are the chief 

 agents in fertilising the flower. Darwin, in fact, in a well 

 known passage in The Origin of Species, records that red 

 clover sets very little seed if the flowers are covered and made 

 inaccessible to bees. He also quotes Newman as believing 

 that mice destroy many humble-bee nests and that near 

 villages and small towns humble bees tend to become more 

 numerous because cats destroy many of the mice. Although 

 this observation needs to be better substantiated, it suggests 

 that there may be a complex, double relationship between 

 mice and bees, the mice being not only enemies but also 

 providers of nesting-places. 



The queen, after starting her nest, has to raise her first 

 brood of workers unaided, but once the workers have hatched 

 they do most of the work, especially all the foraging for 

 nectar and pollen. The queen gradually drops all work except 

 the laying of eggs, and eventually becomes incapable of flight. 

 In fact, she never leaves the nest again once the colony is 

 fully established. Sometimes, in bad years, very worn queens 

 are seen flying in midsummer, and these are trying to raise 

 a new brood after the first one has failed to develop. If the 

 nest goes well several groups of workers are raised, and 

 eventually males and young queens. The cycle is then com- 

 plete and the colony soon breaks up. This may happen 

 surprisingly early, even by late June in some species in a 

 good year. The young June females enter winter-quarters 

 at the height of summer. Apparently there is no time for them 

 to start and to bring safely to completion a new colony in 



