Do Honey Bees Hibernate?

As I was walking from my house to my car on my way to work this morning, I noticed a honey bee lying on my sidewalk. Two days previous, I had seen a dead honey bee on the window sill right above this spot on the sidewalk, so I checked to see if maybe this bee had fallen from its perch. It had not. The bee on the window sill and the bee on the sidewalk were both honey bees, and both had met their demise near my front door.

This got me to thinking. Where do honey bees go in the winter time? Why had these bees unfortunately strayed too far from warmth and safety and perished in front of my home?

It may come as no surprise that honey bees spend the cold winter months in their hives. But what they don't do is hibernate. Instead the bees form what is called a "winter cluster." The worker bees huddle and swarm around the queen bee, who is at the center of the cluster, and shiver in order to keep the center warm. The worker bees move in and out of this cluster so that no bee gets too cold in the outer layers of the cluster. I suppose this is similar to a March of the Penguins style when the males watching the eggs during the coldest months of antarctic winter form a rotating huddle and move in and out of the huddle to keep each other warm.

Studies of over-wintering honey bees have shown that the hive consumes about 30 pounds of stored honey during the winter months. The honey that bees work so vigorously to store during the spring, summer, and fall makes the hive's survival possible. Heat energy is produced by the oxidation of the stored honey and this heat is circulated throughout the winter cluster by the wing-fanning of worker bees. The center of the cluster hovers around 80 degrees Fahrenheit, and the outer edge stays around 46-48 degrees Fahrenheit. The colder it gets outside, the tight the cluster becomes to keep everyone warm.

So why were there two dead honey bees near my front porch this morning? Honey bees stop flying from the hive when the temperature reaches around 50 degrees Fahrenheit. At this time the temperature gets too cold for the bees to be able venture far from the hive without risking death of exposure. There is also not much reason for the bees to leave the hive because there are no flowers in bloom from which to collect nectar. But the bees still need to be able to eliminate their bodily waste, as bees are very tidy creatures. On warmer days, the bees will venture out of the hive to do this. These flights are very short and the bees generally do not venture far because they can't make it back to the hive if they get too cold.

This must be what happened to my resident honey bees. It did get rather warm on Sunday afternoon and yesterday afternoon and the bees were probably taking advantage of the few hours of radiant sunlight. There must be a hive somewhere near my house, but a bit too far for the bees to make it back safely. Hopefully these two will be the last that make it this far before heading back home to the life-sustaining warmth of their hive.

References:

Bug Info - Where Do Insects Go in the Winter? - text

Dave's Garden - text and hive diagram

Honey Bee Photo