Respiration Rates of Worker Honeybees of Different Ages and at Different Temperatures

Abstract

1. The respiration rates of individual adult worker bees confined in small gauze cages were determined over a range of temperatures between 7 and 46° C. The respiration rates usually remained constant over a period of 1 hr., although at 7, 12° C., and possibly at 17° C. there were indications of a decrease with time, and at 42 and 46° C. indications of an increase with time. Fluctuations which would have reflected variable activity during any of the experiments were rare. 2. At each temperature studied the respiration rates increased progressively from the youngest adults (newly emerged) to the oldest measured (24-33 days). The increase was particularly marked during the first few days of adult life. 3. The respiration rates of newly emerged and 18 hr. old adults increased progressively between 7 and 46° C., but 4-33-day-old bees showed two peaks (at 17 and 46° C.) with a depression having a minimum value at 32° C. lying between. 2-day-old bees had similar peaks at 22 and 46° C. 4. It is suggested that the first peak in the respiration rate of the older bees occurred at the lowest temperature at which free movements were possible, and that it indicated an increased body temperature maintained by the bees to combat the effects of the low environmental temperature. The lack of this first peak in the case of the youngest bees is thought to mean that they were unable to raise their temperature above that of the environment. The information obtainable from the literature supported these conclusions; their implications in relation to the regulation of temperature within the colony are discussed. 5. Numerical values for the oxygen consumptions of adult bees are discussed in relation to those found by other workers.