As the autumn colors begin to emerge and the temperatures start to drop, many animals begin their preparations for the winter ahead. Each type of animal has its own strategy for surviving the cold winter months-bears hibernate, some birds fly south, and squirrels and chipmunks begin storing nuts and seeds for the long days ahead. Insects are no different; many hibernate in various developmental stages, but few are active all winter long.
That's where honey bees are different. Note that I said honey bees, not just bees; that is because some species of bees like the Carpenter Bee tunnel into wood and hibernate during the winter. Look at Bumble Bees; the only bumble bees to survive the winter are the queens. But as I mentioned earlier, honey bees are different; they are active in the hive all winter long. Doing what you may ask? Their sole job is to generate heat to keep the Queen warm.
Queen bee surrounded by workers
Preparations for winter start as early as August in the hive. At this time, the colony starts producing winter bees. These bees are physiologically different than the summer bees, they are designed to withstand being confined to the hive for long periods and live much longer than the summer bees. Where summer bees typically live for about 4 to 6 weeks, winter bees can live as long as 4 to 6 months.
As the temperatures begin to drop and the supply of nectar and pollen begins to wane, additional changes inside the hive start to occur. Come October/November egg laying tapers off and the worker bees start kicking the drones, the male bees whose sole job is to help with reproduction, out of the hive. The reason is twofold: they are not able to do their one and only job which is to mate with the queen, and they are a drain on resources.
Drones being kicked out of the hive
When the temperature drops below 55 degrees F, the bees stop flying and begin to form a cluster around the queen. When it drops to 25 degrees F or below, the bees on the inside of the cluster begin vibrating their wing muscles generating heat and raising the internal core temperature of the cluster. The bees on the outside of the cluster remain motionless and act as an insulating layer. You might be thinking, "Wow, that stinks to be the bees on the outside of the cluster;" but don't worry...the bees are very fair and keep rotating so those on the outside get a chance to move near the center of the cluster to warm up. How warm does the cluster get? Surprisingly warm! The temperature ranges from 45 degrees F on the outside of the cluster up to 90 degrees F at the center.
In order to generate all that heat though, the bees need energy. You know all the nectar and pollen that the bees were busy gathering over the summer? Well all that honey that they made isn't meant for us; it is what they depend on to get them through the winter. Some beekeepers say that a healthy hive needs about 60 lbs of honey to survive the winter. That is a lot of honey! Throughout the winter the cluster will move around the hive eating their honey stores.
What are some things that we can do to support the bees? For one, feed them. To help ensure they have enough food stores, we feed the bees a 2:1 sugar syrup in the fall then shift to sugar cakes as it gets colder. Another thing we can do is prevent predation – there are a lot of hungry animals that would love to eat the honey. By placing a mouse guard over the entrance we reduce the chances of rodents getting inside and eating the stores. If the temperatures drop down near zero, we will also wrap the hive with insulation to help prevent the inside temperature from dropping so low that the bees can't move. Only time will tell if these measures are successful, I am keeping my fingers crossed that they are.
Mouse guard at hive entrance