How insects behave 



Everyone knows the bumblebees, of which there are about fifty dif- 

 ferent species in North America and numerous color- varieties. They 

 have reached the same level as the social wasps, and their life-story is 

 similar. The fertilised queens hibernate and appear in spring to make 

 a nest. This is in some existing hollow, especially the empty nest of a 

 field mouse or vole, where on a layer of moss or leaves the bee makes 

 a waxen cell, provisioning it with pollen and honey, and laying several 

 eggs in it. She looks after the larvae that emerge, and gives them more 

 food when they need it. Sterile female workers gradually take over the 

 duties of foraging and cell-building, and the queen finally does nothing 

 but lay eggs. In late summer fertile females and males appear, and after 

 mating only the fertilised females survive the winter, to begin new colo- 

 nies in the spring. 



The most completely social life among bees is that of the honey-bee. 

 Apis mellifera, which is now almost entirely a domesticated species, but 

 which is beheved to be descended from a wild ancestor in the East. A 

 colony may contain more than 50,000 bees, and may go on from year to 

 year indefinitely. 



Like the other bees, and the wasps, a honey-bee colony is dominated 

 by a queen, and there are two other castes, workers and males (or drones). 

 All the workers are sterile females, and the only function of the drones 

 is to take part in a mating-flight, when the queen is fertilised once for 

 her lifetime. 



The workers build and maintain a comb of hexagonal cells, some of 

 which are used for breeding purposes, and some as stores of honey for 

 winter food. The comb is of wax, which the young workers produce 

 from glands in the abdomen. The queen lays one egg in each cell of the 

 brood comb, and when the larvae hatch they are fed by workers. 

 Carbohydrates are supplied in the form of honey and pollen, and pro- 

 teins in the form of 'royal jelly', which comes from glands in the mouth 

 of the workers. 



Males (drones) develop from unfertilised eggs, which the queen is 

 able to lay by omitting to expose them to sperm from the spermatheca. 

 These eggs are laid in special drone-cells, which are bigger than the 

 average. Eggs that have been fertilised always develop into female bees, 

 but whether these bees themselves remain sterile and become workers, 

 or attain full sexual development and become queens, is determined by 

 the diet upon which the larvae are reared. Nearly all the larvae are fed 

 mainly on honey and pollen, and on this diet they remain sterile, and 

 become workers. From time to time the workers construct queen- cells, 

 much bigger than the rest, and hanging down from the comb, and the 

 larvae in these are fed entirely on royal jelly. 



When the hive becomes overcrowded, the queen leads a swarm of 



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