What Happens to Bees in Autumn & Winter?

Have you ever wondered what happens to bees in the colder months of the year?

Contrary to popular belief, not all bees hibernate.  Unlike some bumblebee species, honey bees never hibernate; they remain active all through-out the year.

Certain species have different behaviours and strategies for surviving the winter period; although with the influence of climate change and our winters becoming more milder year after year, studies have shown some species are already adapting their behaviour.

Honey bees in the winter

With the drastic decline of wild honey bees over the past few decades, the majority of our honey bee population is managed by beekeepers.  Managed honey bees thus rely upon good beekeeping practices to see them through the colder months - such as ensuring ample honey is left within the hive.

Towards the end of summer, the honey bee colony is already preparing for winter.  Most drones (male honey bees) are evicted from the hive.  Drones have one purpose only - to mate with a queen.  They do not perform any hive maintenance duties or collect nectar or pollen.  Having less mouths to feed strengthens the colony's chances of lasting through the winter.

In the spring and summer months, the queen produces "summer honey bees", these bees have a maximum lifespan of six weeks, however, as autumns approaches she produces "winter honey bees" - the physiology of these bees are adapted to cope and last through winter; having a maximum lifespan of six months. 

As the temperature drops outside, the colony begins to move upward in the hive to where it is warmest and starts to form a cluster around the queen and any brood (although egg laying is drastically reduced or suspended in deep winter).  The sister bees take turns to protect the centre of the cluster keeping it at a certain temperature, between 34-36°. 

On mild winter days, some will leave the hive to take cleansing flights (dispose of waste); rarely will they leave the hive once the temperature has dropped below 10 degrees. 

The colder it becomes, the tighter and more compact the cluster becomes; in this formation, the cluster moves around the hive to feed on their honey stores collected through the summer. 

Bumblebees in the winter

Unlike honey bees, bumblebee species, like the red-tailed bumblebee hibernate throughout winter.  Bumblebees are able to tolerate colder temperatures and can often be seen foraging on winter flowers right up until November.

Towards the end of summer, old queens will begin to produce new queens and males who then leave the nest to be mated.  Old queens, workers (females) and drones eventually die off, leaving the new mated queens to prepare for hibernation. 

The hibernation period can last around six months; the queen bumblebee will therefore need to drink lots of nectar to build up her fat reserves and achieve a certain weight to increase her chances of survival.  She will then seek a suitable place to hibernate.

Bumblebees build their nests underground, often under tree roots or abandoned rodent tunnels. 

Hibernating bumblebees are able to survive extreme temperature drops, as low as minus 19°.  When the temperature drops to a certain point, a chemical is automatically produced within the queen's body, which acts like an anti-freeze and prevents the fluids in her body from crystalising. 

Upon receiving the signs that spring has begun, the queen will emerge from hibernation to begin a new cycle of life.

Next blog:  Why We're Saving the Wrong Bees