GROWTH AND FEEDING OF HONEYBEE LARVAE. 31 



a change does occur, but that there is also a remarkable change in the 

 type ot feeding, and that this change occurs at the time when the 

 character of the food changes. It thus becomes necessary to point 

 out that the change in food occurs not on the fourth day, as commonly 

 stated, but much earlier. This is further substantiated by the work 

 done by Sturtevant and the writer, recorded in Part I of this bul- 

 letin. 



As has been stated earlier, the number of visits for each 10-minute 

 period averages 5.93, 6.4 and 5.79 for the egg, 1-day, and 2-day 

 larvae, respectively. For these same ages the time in seconds spent in 

 nursing (each period more than two seconds) is as follows: 6.5, 

 20.73, and 5.93. Such a change, on superficial consideration, appears 

 inconsistent, since one naturally supposes that a 2-day larva would 

 require more visits and more time spent in nursing than does the egg 

 or the 1-day larva. The time spent in nursing the 1-day larva is ac- 

 tually over three times as great as the time for the 2-day larva. 



This whole matter is unexplained until it is viewed in the light 

 of the results obtained by Sturtevant and the writer in Part I of 

 this bulletin on the amount of food found within the cell for larvae 

 of different ages. No food is ever found in the cell with the egg, 

 while the weight of food within the cells containing 1-day and 1.4- 

 day larvae averages 3.96 and 3.23 milligrams, respectively. If now 

 these findings are taken into consideration with the well-established 

 fact that there is a change in the character of the food of the 

 worker larva, the whole matter is explained. Immediately following 

 the hatching of the egg, the nurse bees surround the young larva 

 with food in relatively large quantity. As pointed out, this first 

 supply of food may weigh 3.96 milligrams per cell, which is equal 

 to almost four times the weight of the young larva which it supplies. 

 These figures indicate that, as already suggested, a large amount of 

 food is placed in the cell of the recently hatched larva and that 

 during the second day little or no feeding is done, since the atten- 

 tion given (in number of visits as well as in time in nursing) is 

 about equal to that given the egg. Since the egg is never surrounded 

 by food, this indicates that the attention given the 2-day larva is 

 of no greater significance than that given the egg, so far as the giv- 

 ing of food is concerned. That there is a rapid giving of food on the 

 first day followed by little or no supplying of food on the second day 

 is further supported by a comparison of the weights of food con- 

 tained in the cells with larvae of these ages. Nelson and Sturte- 

 vant show that there is a decrease of 0.73 milligram in the amount 

 of food in the cell on the second day. During this interval there 

 is an increase in the weight of the larva of 0.34 milligram so that 

 the decrease in weight of available food exceeds the increase in 

 weight of the larva. The difference (0.39 milligram) is doubtless 

 accounted for by the total combustion of food by the rapidly grow- 

 ing larva. Larvae of this age are doubtless too small to ingest 

 more than the amount of food represented by the decrease in weight 

 of the available food, from which it follows that little or no food 

 is given the larva on the second day. 



On the third day there is a slight increase in the amount of time 

 spent by the nurse bees within the cell, and this indicates that feed- 



