What happens to bees in the winter?

Our precious British bees have various strategies for coping with the winter months. Find out more about how they survive the cold weather.

Huddling honeybees

When it gets too cold to work and fly, Honeybees huddle together in the hive to retain warmth. The ultimate aim is to keep the queen snug in the centre. Being hive-bound, their honey stores provide a crucial lifeline, keeping up their energy levels. However, since they are awake they are ready to go and seek out fresh nectar on warmer winter days.

Bee-keepers may provide their colonies with feeders of sugar syrup to keep them going through these leaner months, especially if they have taken honey that year. This is the time when feral colonies (those away from hives such as in tree holes) often perish, but their fortunes appear to be changing, perhaps due to milder winters.

Burrowing bumblebees

The various species of British bumblebee have a very different strategy to honeybees. They have an annual life cycle. After the new queens are produced and mate in the summer and autumn, the workers, males and old queens die off by winter time.

Typically, the newly-mated queens hibernate through winter. They burrow into soft earth or under logs and stones to escape the frost, preferring north-facing banks where they will avoid being warmed up too early by the winter sun. Despite this, some may still emerge confused on warm winter days.

However, over the past decade or so, things are changing. Some queens choose to start new nests instead of hibernating. These overwintering nests are more common in the milder southern counties, especially in urban areas where they are fueled by winter-flowering garden plants, such as mahonia and heathers.

This increasing trend was first noticed in the Buff-tailed bumblebee, but the Early bumblebee and Tree bumblebee are following suit. This phenomenon has even seen bumblebees flying on Christmas and New Year’s day!  You can record your sightings of winter-active bumblebees on the Bees, Wasps and Ants Recording Society website.

Sleepy solitary bees

Solitary bees are diverse, with varied lifestyles and you can learn to identify different types with our handy bee identification guide. They overwinter in different ways depending on the species. Unlike honeybees and bumblebees, all the adults generally die off before winter comes. The hard-working females have left their eggs sealed inside a nest in a cavity or burrow, provided with food stores of pollen and nectar. They even line their nests with waterproof secretions, to protect their young from damp.

Solitary bees which emerge in the spring, such as Tawny mining bees, Ashy mining bees and Red mason bees will grow from egg to adult over the summer. During the winter, the new adults sit tight in their cocoons in a sleepy state of torpor. In this way, they are primed and ready to break out when the temperature rises, so they can take advantage of spring blossoms such as willow, blackthorn, hawthorn and orchard trees.

If the nests are dug out by people or other animals, the bees will evacuate early, which could explain winter sightings of some solitary bees.

Solitary bees which emerge in late spring or summer, such as Leafcutter bees, Wool carder bees and Yellow-faced bees will grow from egg to larva (grub) over the summer, and overwinter in their larval stage. Since it may be too cold to feed and grow, these larvae also enter a state of torpor where they use little energy. Come spring, they will pupate and turn into adults which fly out to feed on summer blooms.

Few solitary bee species overwinter as adults in the UK.  Some Furrow bees are notable exceptions. They mate in the autumn, after which the females may go to ground in a burrow over winter, emerging to nest and lay eggs the following spring. This only happens in the Southern counties, where the milder weather allows for an autumn mating season. On warm winter days in the south, the overwintering southern females may make excursions to feed. In Cornwall, some have even been seen as early as January.

How to help bees during the winter

1. Plant winter-flowering plants
   Plants such as mahonia, heathers, winter honeysuckle, winter aconite, hellebores and snowdrop will provide food for overwintering bumblebees and others emerging on warm winter days. 

1. Avoid digging 
   Don't bother digging your garden in winter in areas where you have seen solitary bees nesting.
2. Leave dead stems
   They may have solitary bee nests in them, as well as other overwintering insects. Do a ‘spring clean’ instead.
3. Move your bee hotel
   If you have a bee hotel, move it into a cool, dry place such as a shed or other outbuilding for extra protection from damp and frosts. Don’t forget to put it out again in spring, or leave a window open for the bees to get outside.
4. Create bee friendly habitat
   Make a log-pile, rockery or earth bank in a North-facing area of your garden for hibernating bumblebees.