Temperature changes above the upper hive body reveal the annual development periods of honey bee colonies

Determination of the annual development periods of honey bee colonies can help in synchronising the beekeeper's activities with the developmental stage of individual bee colonies in apiaries. It is proposed to determine the development periods by measuring and analysing the ambient temperature and the temperature above the upper hive body. The temperature above the upper hive body is proportional to the energy which is released during bee colony activities. Throughout the year in 2000, measurements with interval of 15. min of the temperature in 14 honey bee colonies was done in Latvia, in the Riga region. One sensor per colony was located above the upper hive body. The annual curve of the average day and night temperature was approximated by five linear pieces that possibly correspond to particular periods. Explicit transition points to the next period were determined. Five sequential periods have been proposed in the bee colony's development: (1) winter brood rearing, (2) spring brood rearing, (3) summer brood rearing, (4) autumn brood rearing and (5) autumn broodless period. These periods collectively form a hat-like annual profile. All brood rearing periods demonstrate high thermal discipline: the hive temperature follows linear dynamics in spite of fluctuations in the ambient temperature.A simple measurement system and criteria for automatic determination of transition from one period to another for apiary has been developed and tested. Thermal measurements above the upper hive body efficiently determine the transition from one period to another in the apiary. The computational system for the determination of developmental periods should be equipped with at least one ambient temperature sensor per apiary and one temperature sensor per observed bee colony.