PART II. THE FEEDING OF HONEYBEE LARVJE. 



Page. 



Introduction 25 



Methods 25 



Nurse bees 27 



Inspection, type A 27 



Inspection, type B 28 



Nursing 1 28 



Number of visits 29 



CONTENTS. 



Page. 



Nurse bees — Ccntd. : 



Time spent in nursing 29 



Change in feeding behavior 30 



The labor of the nurse bees 33 



Summary 34 



Tables 5 to 7 35 



INTRODUCTION. 



The larvae of most bees are supplied with a mass of food consist- 

 ing of a mixture of pollen and honey, which is put in place before 

 the egg is laid. The larvae of the honeybee, on the other hand, are 

 fed at frequent intervals during the period of larval life. This be- 

 havior of the honeybee involves the services of nurse bees in caring 

 for the larvae. The nurse bees are always worker bees, usually 

 those less than a month old. When worker bees are acting as nurse 

 bees they take honey (or nectar) and pollen from adjacent cells of 

 the comb and from these two materials elaborate the food on which 

 the larvae live and grow to maturity. 



The food given to the youngest larvae is a grayish-white paste- 

 like material which is placed in the cell beside the larva. For 

 older larvae the prepared food is mostly fed directly to the larvae. 

 To supply food to a larva the nurse bee must enter the cell head 

 first, so that it is impossible for one to see what occurs in the cell 

 while the nurse bee is so situated. Because of the fact that the larva 

 is wholly hidden while the worker is attending it, one can deter- 

 mine only the total time spent in this work, without being able to 

 divide the time according to the various actions which may occupy 

 the nurse bee during this activity. Attention was attracted to this 

 phase of the feeding problem by the observation that nurse bees 

 spend considerably more time in cells containing well-developed 

 larvae than they do in cells containing eggs or young larvae. To get 

 accurate data on the inequality of the time spent in feeding the 

 present observations were begun. 



As explained in Part I of this bulletin, Mr. Sturtevant was at 

 the same time engaged in determining the rate of growth of the 

 worker larvae. His results showed such a striking correlation with 

 those obtained for the time spent by the nurse bees in feeding that it 

 was decided to cooperate in determining the correlation of the 

 weight of larval food contained within the cell during each day 

 of the larval period with the weights of the larvae for each day. 

 These results have been incorporated in Part I. 



METHODS. 



All observations were made on a colony of bees in a dark room, 

 using artificial light. The hive used was especially designed to ex- 

 clude all light from the brood nest except that used by the observer. 



25 



