Factors Influencing the Lifespan of Bees 237 



the variations in lifespan can be traced to the physiological 

 condition. The closest correlation was found between the 

 development of the fat body and lifespan ; the least close was 

 that between ovary development and lifespan. The result of 

 this statistical evaluation confirmed the biological investiga- 

 tions which showed that the main function of the fat body is 

 the storing of protein, glycogen and fat, whereas the pharyn- 

 geal glands not only serve as a store, but perform other 

 important functions such as the secretion of larva food and 

 the enzymes necessary for honey production. The functioning 

 of the ovaries of the workers is mainly controlled by hormones 

 and in the queenright colony the ovaries remain undeveloped 

 (Butler, 1954, 1955, 1956; Pain, 1954, 1958; and Voogd, 

 1955). Thus, of all the organs examined, it appears that the 

 fat body plays the most important role in the regulation of 

 lifespan of the summer and winter bee. 



A further problem is posed in deciding which substances in 

 the pollen are responsible for the activation of the physio- 

 logical condition and lengthening of the bees' lifespan. 

 Pollen is rich in carbohydrates, fats, proteins, vitamins and 

 minerals, but the concentration of any one of these substances 

 varies greatly from one plant species to another (Hay dak and 

 Palmer, 1938, 1940, 1941, 1942; Haydak and Vivino, 1943, 

 1950; Hejtmanek, 1943; John, 1958; Kocher, 1942; Pearson, 

 1942; Sarkar et ah, 1949; Todd and Bretherick, 1942; Vivino 

 and Palmer, 1944; Weaver and Kuiken, 1951; Weygand and 

 Hofmann, 1950). For instance, the protein content of dif- 

 ferent types of pollen can vary as much as 5 to 35 per cent, 

 and the spectra of amino acids present may be variously 

 composed. It was found that pollen contains the following 

 vitamins: B^ (thiamine), Bg (riboflavin), Bg (pyridoxine), 

 nicotinic acid and biotin. Moreover vitamin K, w^hich is not 

 normally present in fresh pollen, was found in pollen obtained 

 from comb cells. Bees have sufficient carbohydrates at their 

 disposal in honey, thus pollen is their main protein and vit- 

 amin source. Over the last few years many lively discussions 



