The relatively cold weather of late, here in northeast London, has been playing on the mind of ‘the allotment gardener of Nowhere in particular’. He has been fretting about the well being of the honeybees in our allotment apiary; in particular, how they have been standing up to the sub-zero night-time temperatures. We opened up the hives earlier in the month to administer some oxalic acid treatment for varroa mites. We found each of our hives contained a large cluster of bees; a phenomenon measured by the number of frames apparently occupied by the little creatures. This was a very good sign considering the cold spell over Christmas and New Year. It wasn’t just that there were a lot of bees it was also that the hives were still heavy with honey stores and the bees were feeding from fondant we had placed at the top of the hives.
Honeybees form a cluster in the nest or hive in winter. One explanation of this phenomenon is that a mass of bees clustered together, as a more singular entity (the social endotherm), has a lower surface area to volume ratio than an individual bee and therefore less heat is dissipated to the atmosphere. The inner cluster temperature might reach as high as 35degrees centigrade – warm enough to prevent the queen bee from succumbing to cold. One of the issues or problems beekeepers have to address is how to maintain air circulation in the hive without over chilling the cluster. Air circulation is necessary to prevent condensation building up as a result of the water created by the metabolising/respiring bees in the cluster. Excessive moisture in the hive can encourage diseases. Prolonged cold periods also pose the problem of defecation. The bees will not defecate in the hive and therefore have to wait for warmer spells of weather during which they can make cleansing flights – as well as forage for water. This is all received knowledge as in I have not made those temperature measurements or witnessed bees defecating having emerged from a hive after a cold spell however the explanation makes sense
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