BROODNEST TEMPERATURE DIFFERENCES AND THEIR POSSIBLE EFFECT ON DRONE BROOD PRODUCTION AND DISTRIBUTION IN HONEYBEE COLONIES

Summer broodnest temperatures recorded with thermocouples in honeybee (Apis mellifera L.) colonies varied in relation to developmental brood stage and position within the broodnest. Areas containing empty drone cells were significantly warmer than those containing empty worker cells, while worker larvae and pupae had significantly higher temperatures than those of drones. Worker brood was maintained at a significantly different higher temperature than drone brood in the central broodnest (frames 4-6) while not significantly different in the outer broodnest regions. Drone brood temperatures were significantly lower than those of workers in the upper, lower and peripheral comb octads, while not significantly different in the central octads. In colonies used for temperature readings, the distribution of worker and drone brood was related to broodnest temperature when broodnest position was not considered. A similar relationship, however, was not found for most frame and comb octad positions. Drone pupae distribution patterns found in other colonies could not be related to these broodnest temperature differentials. Since adult bees are responsible for colony thermoregulation, their distribution in the broodnest, in conjunction with brood metabolism, may cause the observed temperature differences associated with developmental brood stage and broodnest position.