What in the world are my bees up to this winter? I get to watch my bees work all spring, summer and fall long but in the winter I don’t physically SEE them.
So, what are they doing in there?
I like to imagine them tucked into their cozy beds, wearing itty bitty nightcaps and slippers, taking their turns checking on the queen…
But really, they are in a formation called a CLUSTER.
A cluster is exactly what it sounds like – a tightly knit formation of bees. These bees are keeping the hive warm using thermoregulation.
The regulation of temperature accomplished by balancing heat gain and heat loss via convection, evaporation and metabolic heat production.
Anatomy of a Cluster
The cluster is a spherically-shaped brood area that aids the colony in maintaining a basic hive temperature in the 59 degree range regardless of outside temperatures.
The outer portion of the cluster is an insulating shell and can be anywhere from 1 – 3 inches thick. In order to form this shell the outer bees will fill all of the spaces between the combs and the empty cells in the comb. They are too cold to move but will still attack if the colony is threatened.
The center of the cluster (where the queen is) is much warmer and way less crowded. The bees in the center tend to the queen and any brood. The outside bees move inward and trade places with warmer bees constantly. This movement combined with general wing movement and brood metabolism helps keep the bees warm. It also ensures that the outside bees survive longer.
The ideal temperature range for the colony is 54 to 94 degrees. When brood is present (starting in January) the hive can be at the higher end of the temperature range.
The bees produced for overwintering are physiologically different than the bees you see foraging in the summer and fall. Winter bees are noticeably bigger. They have large hypopharyngeal glands (the glands used to produce royal jelly for the queen and larvae) and more fat body reserves. These reserves are a whole body storage of food complementary to the colony’s honey stores.
These bees live longer since they have no brood to feed and are not as active. The normal aging process is completely suspended as clustering essentially puts the bees into hibernation.
Warm Winter Days
On warm winter days bees will take the opportunity to break the cluster, move closer to their honey stores, fly, and defecate outside the hive. You will also see house bees removing dead bees from the hive.
These warm spells are instrumental in the overwintering survival of bees and on these days their flight can be pretty intense.
These warm winter days are also when you should observe your hive. You should not open the hive unless you have a really good reason and it is at least 45 degrees out (although I prefer 55 degrees as my bottom temperature to ensure the safety of the bees). If on these warm winter days you see that your bees are still flying, you can relax! All is well.
If you suspect you have a problem then you can go in for a quick inspection or you can open the hive to quickly add some food.
Egg laying for the queen goes dormant in November and December but it resumes in January due to the increasing day length.
The egg laying changes everything.
Now the bees are producing more heat to incubate the new brood which causes energy demands to escalate and food stores to rapidly decline. This is the most stressful time of the year for the colony and they need your help as often as it is safe. Feed them as often as possible to replace diminishing food stores. Use a 1:1 syrup as spring approaches but if temperatures remain frigid, continue to use a sugar board or other solid pollen substitute.
The Buzz on Winter
Bees generally are able to survive anything that winter has in store for them by being able to generate and conserve their own heat. As long as some basic overwintering methods, such as providing a wind block and feeding in critical times, are employed you get to just kick back and relax until spring!
I think I’ll spend my time still picturing my bees in their cute little nightcaps and slippers…
Until it’s time for me to build hive boxes for my large apiary expansion this spring, that is.
Honey Bee Biology and Beekeeping by Dewey M. Caron
Honey Bees and Beekeeping: A Year In The Life of an Apiary by Keith Delaplane