One of the most common questions beekeepers are asked is what happens to the bees when it gets cold outside. Usually sung to the tune of, “Do bees hibernate?”
When it comes to insects, like honey bees, IF they did any such thing, it would probably be “diapause” and not “hibernation”. To be real loose and cavalier with explanations, “Hibernation” is like taking a very long nap and all the vitals become depressed and slow down. Think of it kind of like being in a coma.
“Diapause” is more of a state in which development in something like an insect, say… a honey bee, seems to nearly stop cold while bad and ugly things in the environment around them happen. Again, playing loosely with descriptions, think of it sort of like going into suspended animation when the weather gets too rough to find food or water, etc…
I have had more than one person ask if “diapause” was “The Change” for bees since they were all girls just getting older over the Winter. No, bees have plenty of other reasons to be cranky, they don’t need another one. Though in the Winter, they might actually appreciate hot flashes.
As for honey bees though, they do neither in the cold of Winter. Honey bees are awake and active the whole time. When temps hit somewhere around 57-ish degrees F or lower, the colony will cluster.
Honey bees survive Winter in their nest by “Clustering”. That is, they group together in a ball style shape in and around the wax cells in the combs and as a group, shiver their wing muscles to generate heat. By being clumped so closely together, they keep themselves and each other warm through the Winter. The colder it gets, the tighter they cluster together.
How do they keep up the heat? By eating honey. The bees forage for, make and store honey primarily for times like Winter, so that they will have a full pantry and not have to go outside to get more food. It’s already in the hive. The more they generate heat, the more honey they have to consume to maintain the energy to do it. The faster they go through the honey stores, the more likely it is that bees will starve out in the late Winter or early Spring because the food didn’t outlast the weather.
The closeness of their bodies and even the beeswax combs themselves also help to act as some bit of insulation so as to help keep some of the heat they generate hanging around and keeps them, in however little or greater effect, from using too much energy to soon.