In this winter study post, I look at the honeybee colony throughout the seasons.
Winter to spring
In winter when the days are short and the nights are long, frost bites the air and snow covers the ground, the bees cluster together inside the hive to stay warm. As outside temperatures reach around 18°C the bees begin to huddle and as temperatures continue to fall the colony forms a small, tight ball around the queen. She may have stopped egg-laying completely, but there are still tasks for her workers in a broodless hive.
At the centre of the broodless cluster the bees vibrate their flight muscles to maintain a core temperature of around 21–24°C, while the outer edges are insulated by a layer of resting bees. The bees at the centre of the cluster take turns in changing places with the bees at the edges of the cluster, so everyone has a chance to stay warm! However, many bees will freeze to death during the coldest months of winter; 8°C is thought to be the lower lethal temperature at which a bee will die. Occasionally, on a clear, mild day, the bees will venture outside on a ‘cleansing flight’ to avoid defaecating inside the hive.
The bees tuck into their honey stores, because generating all that heat requires a lot of energy. ‘During the winter a colony will use an average of about 1kg per week just for heat production. (So do not skimp on feeding!)’ says Celia F Davis, The Honey Bee Inside Out.
The population of the overwintering colony is around 10–15,000 worker honeybees and the queen. In late January, as daylight hours increase, the queen begins egg-laying again and the workers raise the temperature for rearing the brood to about 34°C.
Spring to summer
The days grow longer and warmer and the plants begin to flower bringing nectar and pollen. The queen’s egg-laying depends on how much she is fed, so as the weather improves and more forage becomes available, particularly pollen for brood, the queen will lay more eggs. It may be as soon as late February or early March that honeybees are seen flying home laden with baskets of pollen to feed the spring brood.
This is a perilous time for bees. The old, overwintered workers are dying off as brood is increasing and new bees are hatching, but their winter stores are now very low. The colony relies heavily on fair weather to forage to feed the growing number of hungry mouths. Between January and March is when many colonies are most likely to die and beekeepers should keep careful watch.
As spring moves into early summer the queen may lay more than 1,500 eggs a day, including drones to mate with virgin queens. A healthy, well-fed colony should grow from strength to strength and vary from 30,000 to 40,000 individuals at the height of the season. The colony continues to build up from May to June, which is usually the swarming season, although they may swarm earlier or later than this.
The workers put the queen on a diet to make sure that she is light and slim enough to fly – as a result, her egg-laying drops a week or two before the swarm. Swarming causes the population of the colony to fall by about a half and this combined with the break in brood both before and after the swarm, while waiting for a new queen to mate, means that the remaining population must work hard to build up numbers and stores again.
Summer to autumn
The longest day of the year has passed and daylight hours grow shorter and cooler. The queen’s egg-laying slows, less brood is produced, fewer bees hatch and the shorter-lived summer workers are dying off. The colony is becoming much smaller in size.
Foragers can be seen bringing home red-jewelled propolis on their legs. This sticky, resinous substance exuded by trees is used to disinfect and insulate the hive as the colony prepares to overwinter. In early autumn, the drones, having served their purpose throughout spring and summer to mate with virgin queens, are evicted by their sisters who do not want to feed them in winter. The bees that hatch in autumn will live for almost six months surviving on summer stores.
The seasons turn full circle as temperatures begin to drop and the colony clusters together waiting for spring to return.
Related links
Visit my blog index for more winter study posts.
A great revision post from Emily Heath of Adventures in Beeland: 3rd Honeybee behaviour revision posts: the queen’s egg laying behaviour & seasonal variations in the size of a colony
Mid Buck Beekeepers Association Blog’s excellent revision notes for BBKA module 6
Recommended reading
Celia F Davis. The Honey Bee Inside Out. Bee Craft Ltd, ISBN-10: 0900147075
Ted Hooper. Guide to Bees and Honey. Northern Bee Books, ISBN-10: 1904846513
Mrs Apis Mellifera 
I did not realise they kept the hive or at least the centre, so warm. It seems an amazing feat. Do bee keepers insulate their hives in winter?
Mmm, psychic, I was just bookmarking your blog to catch up on reading next week – yes, the ‘silly season’ is here again 🙂 Beekeepers sometimes insulate hives for winter as, with open mesh floors, condensation is usually not a problem. Emily and I put insulation in the roof to help our bees stay warm over winter and to keep the fondant soft and warm, so it is easier to eat!
What happens to the frozen bees. Do other workers throw them out of the hive?
That’s a good question. I am not entirely sure as I haven’t come across this specifically in the books.
During spring and summer some workers have ‘undertaker’ duty but heaving bodies out of the hive and flying them off to be dropped at a distance requires energy and eating up honey.
During winter beekeepers sometimes report more dead bees lying on the floor or at the entrance of the hive, which is may be for many reasons – one of which that ‘undertakers’ are less inclined to fly dead bodies away from the hive and just dump them outside. Certainly more dead bees are found on the floor of the hive after winter than in summer, perhaps having died and dropped out of the cluster but no one has enough energy to clear them away.
Bees are often found frozen on the comb or inside cells, at the time of the shook swarm in spring, and it is thought that they strayed too far from the cluster to collect food stores for the colony, and froze to death. For this reason, Emily and I punch a hole through the centre of each brood frame to make a central tunnel for bees to have easy access to honey stores throughout winter (a trick John Chapple taught us, he’s done this for all his hives for years).
Thanks Emma. Bee hives are pretty complex. No doing their ‘chores’ also is to benefit the hive as a whole. No sense in taking a chance on losing another member.
We have heard that sometimes the dead bees pile up high enough to clog the bottom entrance. The fans of top entrances look smug at that point.
May we request a post describing that central hole punching trick in more detail? Offhand we would like to hear: What do you use? Hive tool or pointy stick? How big a hole? Why only brood frames? Do you do this just before winter or earlier? Do the bees ever fill in the hole?
That’s a good question, so I will post on this technique in more detail with pictures! It is a method that John taught some of us at a monthly meeting.
It is something that you might do as the weather cools in late September and when it looks like it might be the last time the hive will be opened before winter. The hive tool is used to make a hole in the centre of each brood frame (not very big, just the size of the head of the tool) thus creating a ‘tunnel’ through the hive. I suppose you could also use a pointy stick.
During winter bees leave the cluster to collect honey to eat and gradually venture out further and further as honey in the centre and surrounding the cluster is eaten. A tunnel may make their life a little easier by creating more direct access from the cluster to honey stores on the outer brood frames, rather than making the bees climb over or under brood frames to reach stores.
They don’t tend to fill the holes with comb because they’re not building comb in winter.
All beekeepers have their own particular methods, this is just one that could be tried. We did it for our hives last year and the bees didn’t object. The brood frames are replaced in spring so it doesn’t matter that they are damaged.
I suppose it could be done to the frames in the super, although you may want to reuse the super frames the following year and this would damage them. Also, the bees tend to stay and use up honey in the brood box first, rather than venture into the super.
And yes, dead bees might clog up the entrance so we usually check the entrance is clear regularly during winter. (I still wear my suit in winter when doing this, as sometimes a bee or three might fly out and be surprised to see me!)
I am launching a new website for my association next year which will include posts on tips by members, so hopefully this will prove useful too.
The bees were flying at the apiary yesterday. It was interesting to see that the yellow New Zealanders were flying the most; the darker bees did not seem to be flying much. The New Zealanders may be wasting more energy by flying when there’s no forage about.
I love David Attenborough’s video showing how queen bumblebees manage to fly at only a couple of degrees above freezing, I think maybe you have posted it on your blog before – http://www.youtube.com/watch?v=R-o6e57AEGo.
I love SDA! Thanks for the link, this is very enjoyable to watch.
Those naughty NZ bees, I just don’t think they are well-suited to our climate. Our mongrel London bees are much more streetsmart!
I posted about the bazinga bees! Here’s the link: http://standingoutinmyfield.wordpress.com/2012/12/20/bazinga-bees-are-less-than-humble/
Great, popping over there! 🙂
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I learn a great deal about bees on your blog. Informative.
Thanks, Alex. Blogging has been a useful way to motivate and structure revision, although the further I get along the syllabus the more I realise I don’t know. Would be great if there were advanced courses on bees as well as the hundreds of beginner classes!
Study aside now, hope you have lots of fun planned for New Year’s Eve!
I love this blog.
Kindly accept my nomination for the Award: Blog of the Year 2012.
All the best…
That is so kind, thank you. Looking forward to another year blogging on excellent WordPress community!
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I worry your temperatures might be a bit off at the start of this post. They dont ball at 18c or in the uk they may stay in the ball until mid summer. And I thought the temp in the ball was closer to 31-34C, not low 20s.
Hi Nick, that’s a good question and I think the temperature ranges need to be made clearer at the beginning of the post, which I will edit. I followed Celia F Davis and Ted Hooper as guides for temperature ranges for bees beginning to cluster, in cluster and for broodless/brood rearing clusters, which are copied below:
“When the weather starts to turn cold the bees have to adopt a different strategy. At about 18°C they begin to huddle together in little groups and as the temperature falls a single cluster is formed which gradually gets tighter until, at 0°C, it is as tight as it ever gets… If the colony is broodless the temperature in the middle of the cluster is probably kept to around 20°C.”
Celia F Davis The Honey Bee Inside Out p146-7
“As the environmental temperature falls below about 18°C (64°F) the bees begin to cluster together, forming a ball with the combs running through it… By the time the temperature falls to 13°C (55°F) the cluster is completely formed… The temperature in the centre of the broodless cluster is kept at about 20° to 30°C (68-86°F)… Once brood rearing begins the brood area has to be maintained at temperatures of 32-36°C (90-97°F) or the larvae will die.”
Ted Hooper Guide the Bees and Honey
I hope that’s useful!
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