28 BULLETIN 1222,, XT. S. DEPARTMENT OF AGRICULTURE. 



INSPECTION, TYPE B. 



On other occasions a nurse bee approaches an open brood-cell, 

 pauses, lowers her head and thrusts it into the cell, but withdraws 

 it almost immediately. The whole head may be thrust within the 

 cell and perhaps part of the thorax as well. When the whole time 

 of this operation does not exceed two seconds, it is assumed that there 

 is not time for the nurse bee to do anything in the nature of actual 

 feeding. Two seconds might allow time for the ejection of a liquid 

 food, but such a short time is probably insufficient for a determina- 

 tion of the already available food supply or the needs of the larva 

 and then additional time for supplying such food as may be needed. 

 In taking data on the time spent in caring for the brood, all such 

 activities are designated Inspection, Type B. That bees do determine 

 the quantity of food present is evidenced by the fact that all larvae 

 of approximately the same age and position on the comb have about 

 the same amount of food at all times. This would not be the case if 

 the different nurse bees did feeding indiscriminately and without a 

 determination of the amount of food already within the cell. There 

 is opportunity in the form of activity under this heading for tactual 

 contact with the larva, while in the former type (Type A) there is 

 no such opportunity. 



NURSING. 



Feeding of the larva occurs when the nurse bee enters the cell, but 

 obviously an appreciable time is required for this activity. For such 

 activity the descriptions under the two preceding types of inspection 

 are not valid. While the nurse bee is within the cell, activities other 

 than actual feeding may occupy part of her time, but probably all 

 these activities have to do with the care of the larva. 2 



The time spent by a nurse bee within the cell engaged in feeding 

 varies between 2 seconds and from 3 to 4 minutes. Even the shortest 

 periods may be distinguished from inspection by the fact that there 

 is a noticeable pause of the bee while within the cell. The longest 

 periods mentioned are quite exceptional. It is impossible to see what 

 a nurse bee is actually doing within a cell, but some basis for a 

 differentiation between inspecting and nursing visits should be 

 adopted, even though it appears more or less arbitrary. The most 

 practical basis appears to be that of time. When the time spent 

 within the cell is less than 2 seconds the visit is classed as an in- 

 spection, and when the visit is of longer duration it is considered 

 under the designation nursing. This basis does not appear so arbi- 

 trary to the observer, since the actual behavior in these two cases 

 appears rather more distinctive than the difference in time alone 

 would cause one to believe. While it is quite possible that occa- 

 sionally an inspecting bee may spend more than two seconds, it is 

 nevertheless true that most inspection visits are completed in less 

 than two seconds. 



Having, therefore, decided upon this method of classification of 

 the behavior of the nurse bees, observations were begun. The results 



- Occasionally a worker bee creeps into a brood-cell containing a small larva merely to 

 rest. Such a worker may usually be distinguished promptly from a nurse bee engaged 

 in her duties of feeding. 



