THE COLLECTING PERFORMANCE OF HONEY BEES UNDER LABORATORY CONDITIONS

¹ Department of Biology, Sweet Briar College, Sweet Briar, Virginia
² The Institute of Zoology, University of Munich, Munich, Germany

1. The collecting activity of honey bees, Apis mellifica, maintained in a bee laboratory, was recorded automatically through two different periods, the first of 40 consecutive days, and the second of 30 consecutive days. During both these periods, a two-molar sucrose solution was available at all times, and the temperature and humidity were constant. During the first period of recording. the light intensity was also constant at approximately 1000 lux. This was true also of the second period with the exception of four times when the laboratory was dark. Under these conditions, workers continued to collect the sugar solution, and the colony remained in good condition. Therefore, such a population is favorable for long-term observation and experimentation.

2. During both these periods of recording, the average daily collecting activity varied from day to day; however, these variations were not regular or cyclic. The period or frequency of cycles described in terms of hourly levels of activity and solar time was found to vary from 19 to 29 hours, and the mean value was 23.± 2.40 hours. Several different forms were described by these parameters and changes from one to another were not always gradual, but were saltatory in nature. Changes in light intensity did effect greater precision of the cycles probably by synchronizing the rhythms of individual workers.

3. The results are discussed in terms of biological rhythmicity, and possible explanations for the saltatory nature of the daily cycles are presented.