Winter Bees

By Malcolm Augat

Now that fall’s chill is finally upon us there has been a shift in activity in the hive. The bees are clustering together for warmth, the queen is no longer laying eggs, and brood rearing has stopped. In Virginia, the colony won’t begin raising new bees until February, meaning that the workers raised in the fall must survive 4–5 months until they can raise their replacements next year. In the spring and summer, worker bees typically live for about five weeks — far short of the months needed to make it through the winter. How then do the worker bees manage to live so much longer during the late fall and winter?

The answer is two-fold: First, there is less work to be done in the winter. During the warmer months the worker bees are much more active and work themselves to death (foraging in particular drastically shortens the worker’s lifespan). Second, the bees produced by the colony in the late fall are physiologically distinct from the warm-season workers. These winter bees (also called fat bees, or Romantically called diutinus bees) contain far larger fat body organs and internal food stores. In yet another example of remarkable bee developmental plasticity, winter bees are genetically identical to other workers and queen bees. When larvae are fed worker bee diets that are deficient in protein — as happens in the fall when pollen is more scarce — the larval worker develops into a winter bee instead of a typical worker.

No conversation about honeybees is complete without some discussion of the blight on contemporary beekeeping: the varroa mite. Parasitism of workers by varroa, whether as adults or during development, drastically shortens worker lifespans, including for winter bees. Winter bees who have experienced mite parasitism are unlikely to make it through the whole winter, and if too many winter bees are lost the colony will be unable to stay warm and will die. As such, it is vitally important to treat your hives in the late summer, making sure mite levels are low as the colony begins producing winter bees.

The longer I keep bees, the more impressed I am by them, and so I’ll be doing my best impression of a winter bee this fall: I plan on eating lots of liquid food (soup), growing a fat body, and staying warm heading into winter.