Winter has arrived.

Many beekeepers dread the arrival of winter, as it is a time of uncertainty about whether their bees will survive, and even if the hive itself will make it. A bee colony is a super-organism, and as such, it is susceptible to destruction by natural causes.

European bees know by nature how to survive winter. They have done it for thousands of years. But not in our man-made hives, and not with parasitic varroa mites, which arrived by way of trading and shipping goods, and then invaded bee colonies and their bodies. Due to these human-inflicted changes, many bees now need human help to survive winter. Sadly, one of every three US honeybee hives doesn’t make it.

This video is about 3:19 minutes long and gives extra insight into winter bees:

How would you spend winter if you didn’t have to go to work? Would you—like the bees—stay home with plenty of food to last the winter, a built-in warmth generator and plenty of entertainment?

Bees work all autumn so they can huddle in the hive for up to 4 months and rest all winter, only leaving the hive for occasional hygiene breaks to keep the hive as clean as they can. Once they settle in for winter life, they band together and vibrate their wing muscles to generate heat. The bigger the cluster, the more bees involved, the warmer the bees will be.

The queen bee lays eggs so new worker bees will be born to help her make it through the winter. She knows when to stop laying eggs so there will be enough honey to feed the hive residents throughout the winter. Workers born in the autumn are plumper than those born in the spring and they live longer. They collect and prepare nectar before it gets too cold outside, but once winter sets in they form a thermo-circle around their queen to keep her warm.

As they cluster and huddle, they generate moisture and heat. This is necessary so they can eat, because in cold places the honey will be frozen until the huddle heat thaws out their honey enough to eat. So, the honey ends up being just right—not too hard and not too cold.

While we think of busy bees all summer long, in winter they are relatively inactive in the cool temperatures. The lower activity in the hive means they eat less, so the honey lasts longer. This is not a form of hibernation so much as inactivity.

A recent study led by Mehmet Döke, Ph.D. and colleagues at Pennsylvania State University and Embu University College in Kenya reveals that the best predictors of overwinter survival are colony weight, and the number of worker bees in October, shortly before winter begins. They found that colonies weighing less than 20 kg or 44 pounds had lower survival while colonies weighing 30 kg or 66 pounds had 94% survival rates. Also, an abundance of diverse flowers supports larger populations of worker bees in a colony, and this may increase the chances for overwinter survival.

Döke suggests that beekeepers should build strong colonies with quality queens, control parasitic varroa mites and track colony weight during the summer if they want to maximize overwinter survival. Underweight colonies can receive supplemental pollen and sugar syrup to boost the number of worker bees before winter sets in. Combining small colonies may increase their chance of overwinter survival.

View our recent blog post Bees In Deep Winter to see how amazing bees make it through the winter.