318 '■Wf ANIMAL KINGDOM 



is a major source of protein in the bee diet and must be collected care- 

 fully. The anterior pollen brushes collect pollen from the head, the 

 middle brushes gather it from the thorax and the anterior brushes, while 

 the combs collect it from the abdomen and the second pair of brushes. 

 Each pair of legs is drawn between those behind to effect transfer. 

 Finally the pollen on one comb is scraped off by the pecten of the op- 

 posite leg and it falls onto the auricle. The tarsus is then bent so as to 

 force the pollen up the outer surface of the tibia into the pollen basket. 

 The pollen adheres through its own moisture and may become a sizable 

 mass. Although this sounds like a very complex process, the bee actually 

 does it all in midfiight with very little loss of pollen. 



The base of the first tarsal segment of each front leg has a bristled 

 notch overlapped by a movable spine at the end of the tibia. This is the 

 antenna cleaner. The base of the antenna is fitted into the notch and 

 locked in place by the spine, ft is then drawn through the bristly hole. 

 Above the spine each anterior tibia has a row of short, evenly spaced 

 bristles, the eyebrush, used for brushing off the compound eyes. Each 

 middle tibia has a terminal wax spur for removing plates of wax se- 

 creted on the abdomen. 



The abdomen shows two specializations. Paired, ventral wax glands 

 secrete wax as plates that are used for building the honeycomb. The 

 reproductive apparatus is modified at the posterior end to form a stinger 

 (Fig. 16.27). The tube is formed of a dorsal sheath and two ventral darts 

 that slide on ridges of the sheath. The tips of all three are barbed. The 

 sheath initiates a puncture, after which a seesawing movement of the 

 darts drives the stinger deep into the flesh. Two secretions are mixed as 

 they are extruded through the central canal. That from a pair of acid 

 glands is stored in a poison sac, and during extrusion the secretion of 

 a single alkaline gland is added. The mixture is more poisonous than 

 either secretion alone. When the worker bee stings a mammal and then 

 flies away, the stinger with its glands and muscles is pulled from the 

 insect's body. The bee later dies, but the stinger remains in the mam- 

 mal's flesh with all of its parts still working, the darts driving it deeper 

 and the glands pumping in their poison. 



Connected with the esophagus are large salivary glands which for 

 the first ten days of adult life secrete "royal jelly," the food of young bee 

 larvae. After ten days, however, these glands secrete ordinary saliva con- 

 taining enzymes to digest starch. The crop serves as a honey-stomach 

 where nectar is temporarily stored, as the bee collects it. Salivary enzymes 

 convert the disaccharide, sucrose, of the nectar into the monosaccharides 

 glucose and fructose. In the hive the nectar is regurgitated, concentrated 

 by evaporation in the cells of the honeycomb, and thus converted to 

 honey. 



The life history of a worker reveals additional specializations. Life 

 begins as a fertilized egg laid by the queen in a comb cell (Fig. 16.28). 

 For the first two days after hatching the grublike larva is fed royal jelly 

 by young adult workers, and for the next four days it receives beebread, 

 a kneaded mixture of pollen and honey. The larva molts several times 

 and then spins a delicate cocoon within which it pupates. Adult workers 



