Beprinted from Pstohobiolooy, 

 Vol. II, No. 2, April, 1920 



THE KELATION OF PHOTOTROPISM TO SWARMING 

 IN THE HONEY BEE, APIS MELLIFERA L.> 



DWIGHT E. MINNlCfl 



The honey bee is remarkable for the extent to which many of 

 its activities are controlled by light. Observations and experi- 

 ments demonstrating the strong photopositive responses of this 

 animal have been detailed by Lubbock ('82, p. 278, 279, 284), 

 Graber ('84) and Hess ('13 a, '13 b, '17) . And indeed this feature 

 of behavior must have been patent to many of the earlier workers, 

 so strikingly and constantly is it exhibited. 



While conducting some experiments on the photic behavior of 

 bees several years ago, I was greatly impressed by the strong, 

 positive reaction to light which normal individuals almost 

 invariably displayed. Bees in an active state of locomotion, or 

 "easily excited to such, exhibited an orientation which, for its 

 rapidity of accomplishment and its accuracy of maintenance, 

 was most spectacular. I say bees exhibiting vigorous locomo- 

 tion, for, obviously, bees which are torpid and do not move 

 freely — a condition frequently encountered during cool, damp 

 weather — cannot show phototropism. Even the moribund con- 

 dition seemed often to intensify rather than to weaken photic 

 behavior, and bees scarcely able to creep were observed making 

 a final struggle toward the light. 



My experiments were carried on well into the autumn, when 

 it became more and niore difficult to obtain bees in the field as 

 the flowers became less abundant. I, therefore, installed a 

 single comb of worker bees without queen, in a glass observation 

 hive. The hive was kept darkened by means of small wooden 

 covers fitted to the glass sides, and the exit was covered with 

 a bit of screen wire to prevent the escape of the bees. Animals 



1 Contributions from the Zoological Laboratory of the Museum of Comparative 

 Zoology at Harvard College. No. 321. 



177 



