32 



BULLETIN 1328, U. S. DEPARTMENT OF AGRICULTURE 



necessity of a shortening of the voyages as dusk approaches is 

 apparent, but the cause of the short voyages at the beginning of the 

 day's flight is problematical. It may be that these short trips in the 

 dearth are those made by the water carriers. 



The flights which occurred on May 9 (fig. 13) when locust honey 

 was available, were intermediate between those given above, their 

 average duration in the period of equilibrium being 42 minutes. 

 The bees were obliged to travel a considerable distance. The details 

 of the variation for this day are easily interpreted from the figure, 

 and need not be explained in full. The method of interpretation is 

 the same as for the examples given above. 



These data also indicate that when conditions for a maximum 

 secretion of nectar occur, enabling the bees to gather their loads 

 rapidly and return quickly to the hive, there are relatively more bees 

 within the hive. The significance of this fact with reference to 

 swarming is apparent. 



A LIMIT TO THE NUMBER OF TRIPS AND THE TIME SPENT 



WITHIN THE HIVE 



To determine the number of trips which the bees of a colony of 

 honeybees make in the course of any particular day, it is necessary 

 to know the total number of exits (or returns) for the day and the 

 total number of bees which are participating in the flight on this 

 day. Owing to the limited time available for this investigation, no 

 attempt was made to manipulate the colony periodically so as to 

 take a census of the field bees. With the figures available, however, 

 a lower limit to the number of bees participating in the flight is 

 given by the average number of bees in the field, giving in turn an 

 upper limit to the number of trips each bee could make. For 

 example, May 15 (9.45 to 3) the average number in the field is 

 1,567, so that during this period each bee could not make as many 

 as 32,492-f-l,56T=20.T4 trips, for to maintain this rate these 1,567 

 bees would have to go in and then out of the hive immediately. 



Table 4. — Record of exits and returns, total and per quarter hour, and of bees 

 in the field, July 10, 1922 









Bees 



Exits 



Returns 









Bees 



Exits 



Returns 



Time 



Total 



Total 



in one- 



in one- 



Time 



Total 



Total 



in one- 



in one- 



exits 



returns 



in 

 field 



f ourth 



fourth 



exits 



returns 



field 



fourth 



fourth 









hour 



hour 









hour 



hour 









Number 



Number 



Number 









Number 



Number 



Number 



5.30 























10.15 



3,674 



1,513 



2,161 



434 



203 



5.45 



4 



2 



2 



4 



2 



10.30 



4,699 



1,946 



2,753 



1,025 



433 



6.00 



18 



11 



7 



14 



9 



10.45 



5,212 



2,201 



3,011 



513 



255 



6.15 



32 



19 



13 



14 



8 



11.00 



5,610 



2,595 



3,015 



398 



394 



6.30 



46 



31 



15 



14 



12 



11.15 



5,965 



2,981 



2,984 



355 



386 



6.45 



63 



41 



22 



17 



10 



11.30 



6,600 



3,349 



3,251 



635 



368 



7.00 



160 



73 



87 



97 



32 



11.45 



6,971 



3,613 



3,358 



371 



264 



7.15 



225 



147 



78 



65 



74 



12.00 



7,381 



4, 133 



3,248 



410 



520 



7.30 



332 



219 



113 



107 



72 



12.15 



7,930 



4,792 



3,138 



549 



659 



7.45 



398 



269 



129 



66 



50 



12.30 



8,469 



5,117 



3,352 



539 



325 



8.00 



503 



360 



143 



105 



91 



12.45 



9,242 



5,646 



3,596 



773 



529 



8.15 



612 



438 



174 



109 



78 



1.00 



9,662 



6,134 



3,528 



420 



488 



8.30 



770 



525 



245 



158 



87 



1.15 



10. 197 



6,692 



3,505 



535 



558 



8.45 



887 



609 



278 



117 



84 



1.30 



10, 382 



6,955 



3,427 



185 



263 



9.00 



1,044 



675 



369 



157 



66 



1.45 



10, 965 



7,848 



3,117 



583 



893 



9.15 



1,461 



785 



676 



417 



110 



2.00 



11, 290 



8,197 



3,093 



325 



349 



9.30 



1,923 



907 



1,016 



462 



122 



2.15 



11,851 



8,509 



3,342 



561 



312 



9.45 



2,604 



1,050 



1,554 



681 



143 



2.30 



12, 405 



8,849 



3, 556 



554 



340 



10.00 



3,240 



1,310 



1,930 



636 



260 



2.45 



12,828 



9,366 



3,462 



423 



517 



