Determining the amount of water condensed above and below the winter cluster of honey bees in a North - European Climate
Kalle Toomemaa, Ants-Johannes Martin, Marika Mänd and Ingrid H Williams
The amount of water condensed in the hives of overwintering honey bee colonies was investigated. In autumn, condensers of thin sheet metal were placed in hives above and below the frames of the winter nests of the experimental colonies. The condensed water could flow into plastic bottles for collection. Most of the water collected during the winter condensed on the lower devices, only 2.5 ± 1.31% on the upper ones. At an average food consumption of 7.17 ± 0.35 kg, the amount of water condensed was 445.27 ± 45.8 g. The total amount of water released by such food consumption would be 4.88 ± 0.24 kg. The upper condensers increased moisture and wet surfaces in the hive, whereas the lower ones did not. Test and control colonies did not differ significantly in food consumption and bee mortality. The top condenser created additional airspace above the cluster and probably metabolic water vapour released from the cluster, having risen up first started descending, but due to the longer distance to the lower condenser it cooled more and condensed on the hive walls. The results show that in hives without top ventilation, it would be appropriate to remove descended water vapour from below of the nest or to retain it in the hive for spring consumption of the bees. It enables to reduce humidity in the nest of bees without strengthened ventilation to withdraw increased heat loss and enforces the bees to rise the metabolic rate and heat production, which in turn would increase food consumption and water production.
honey bee, wintering, water vapour, moisture, condensation