In the winter, beekeepers take a break from tending to their bees or at least they have less work to do. They hang the beekeeper suit until spring, when the flowers will bloom once more, but what do the bees do during all this time, while everything outside is getting covered by snow? The answer is pretty simple actually.
When temperatures drop and days get shorter, many animals wait out winter by hibernating or migrating to warmer climates. However, honey bees do something a little different to stay cozy. They hug.
Honey bees start preparing for winter in late summer and fall. The worker bees gather more honey in their hive and tend to the growing winter bees that will replace them once it starts snowing. These replacement insects better endure the harsh conditions of cold weather. They have more fat on their abdomens and live much longer than the regular bees.
The main reason for which winter bees are bigger is that they have larger hypopharyngeal glands and at the same time, more fat reserves. While the bees that live and work during the summer have a lifespan of around five weeks, winter bees can survive for as long as eight months. When the temperature starts dropping, worker bees eliminate male drones.
The male drones are a lot bigger than females and by removing them from the hive the bees are saving the remaining food for the new winter bees and, most importantly, the queen. The female worker bees will literally kick the drones out of the hive, will bite at their wings and will basically kill them. In the fall, dead drones can be found at the base of beehives.
Surviving the winter
Their main task is to keep the queen warm and fed. They do this by forming what is called a “winter cluster”, which is essentially a very big and very warm group hug. The bees from the hive gather around the queen, forming a tight ball. The outer bees are providing some insulation, while the inner bees flex their flight muscles, creating heat.
The thorax of the honey bee is packed with light muscles, muscles that not only power the wings, but also have evolved to produce heat when flexed. The heat production is impressive and inside all this fluttering and shivering of the whole colony, the queen can get quite toasty.
The winter cluster’s diameter is approximately 14 inches at 57 degrees Fahrenheit but drops to 10 inches at minus 14 degrees Fahrenheit. As it gets colder, this group hug tightens to be more efficient in generating and storing heat. The winter cluster has a 3-inch layer of bees on the exterior that is very tightly compressed, all the bees facing inward.
Inside a winter cluster, the queen always remains in the middle of it, and the rest of the bees rotate and take shifts so no bee remains on the exterior for too long. This way, all the bees get their share of warmth. You may recognize this behavior from penguins, who also gather in similar groups and switch position in order to be protected from cold winds and stay warm.
While the extremity of the cluster might be 50 degrees Fahrenheit, or 10 degrees Celsius, the center of this hug can reach a scorching 90 degrees Fahrenheit, or 32 degrees Celsius. These values are being reached while the temperature of the surrounding air can drop to minus 22 Fahrenheit or minus 30 degrees Celsius, so well below freezing.
All that fluttering and shivering is hard work and naturally, work requires food. When the temperatures rise a little, the cluster shifts its position inside the beehive to reach new reserves of honey. A bee colony can eat as much as 80 pounds of honey during winter.
In areas where the climate is more forgiving, bees manage to survive the winter’s temperatures without forming a winter cluster. If the temperature remains above 50 degrees Fahrenheit, some bees will keep collecting pollen all year round.
As the bees require a lot of food to replenish their energy, one of the most important things that beekeepers have to do is to make sure they leave enough honey behind in the fall so that the bees survive through the winter.
Another thing beekeepers do is to add weather stripping on the edges of the beehive lid or door and then close it. Moreover, any existing holes in the beehive box can be plugged with cork so the heat doesn’t get lost through those spaces.
There are many products available to beekeepers that have the purpose of thermally insulating the hive. These products are made from foam or other similar materials and are placed around the hive and fastened together so that the wooden boxes are protected from the snow and wind and better retain the heat generated by the bees inside.
It’s worth mentioning that the hive must not be sealed completely during winter. Beekeepers let at least one hole open because bees still get out of the hive from time to time, mostly on warmer days with temperatures around 50 degrees Fahrenheit, or 10 degrees Celsius, to eliminate body waste. They never do that inside their hive and if they can’t relieve themselves in time, they die.
Although the job of a beekeeper is less intense during winter, he still has some tasks to perform in the cold season. One of them is removing the snow and dead bees, if there are any, from the beehive entrance. Another thing they must do is to make sure the bees have enough food. In late winter or beginning of spring, entire colonies may perish of starvation.
Not much is happening to bees during winter. They stay warm inside their hive around their queen and look after it. However, they could still use the beekeeper’s help from time to time, just to have an easy winter and keep their numbers until the flowers bloom again.