Winter in the Hive

One of the most frequently asked questions I get asked around this time of year is “what do the honeybees do over winter?”. They do a kind of hibernation: as the days get shorter and the temperature drops, the honeybees mostly stay in their hive keeping warm. If they have brood (bee larvae) then the internal temperature of the hive will be around 35°C, but in December when the days are at their shortest, they may enter a broodless period where they’ll allow the temperature to drop to a cool 20°C. So as a beekeeper, I’ve stopped all my inspections of the colony – I really don’t want to be opening the hive and letting all that heat escape if I can possibly help it.

The honey that honeybees make is primarily for their winter stores, to provide the colony with plenty of food to make it through the long, cold winter months when there are few foraging options outside of the hive. Like most hibernating animals, the bees usually overstock their pantry in preparation for the absolute worst-case scenario which rarely comes to pass. So, beekeepers harvest the excess honey to prevent the entire nest being filled to the brim with honey – a term we call ‘honey bound’.

Due to this massive lifestyle change in the colony from summer to winter, the bees living in the colony also see a change in their lifecycle. Over the summer months, worker bees can expect to live about 6 weeks; I’ve sometimes seen this written as 40 flying hours. These so-called summer bees have a hard life, from the moment they emerge from their cells they’re working hard. From feeding the brood, cleaning the hive, processing nectar into honey, guarding the hive, and finally leaving the hive to forage for pollen, nectar, water and propolis. This level of hard living runs the bees ragged compared to their more relaxed winter sisters. In comparison the winter bees have it relatively easy, spending the majority of their life keeping warm in the hive, eating the honey their summer sisters stored and waiting for the weather to warm up. The winter bees have significantly less brood to care for (the colony shrinks in size for winter and the queen may even stop laying in the depths of winter) and the weather is rarely warm and dry enough for them to leave the hive. All of these factors combine and result in winter bees living as long as 6 months!

With the winter bees living so long (from around September/October until March), the beekeeper needs to ensure the colony is as strong and healthy as possible much earlier than many beginner beekeepers think.

Now I must say: it’s only honeybees that overwinter in large colonies. The majority of bee species in the UK are solitary bees which have a much different annual lifecycle; eggs are laid in the spring-summer and provided with their own little pantry of food stores. The egg hatches into a larva which grows until it pupates, the pupa transforms into the adult but doesn’t emerge from its cocoon until the following spring. Other social insects such as bumblebees and wasps have yet another variation with the colony building up over the spring-summer months before producing many queens and drones (males). These queens mate with the drones then hibernate on their own over winter, ready to start their own nest in the spring.

One fun fact I like sharing is that honeybees are very hygienic and they won’t defecate in the hive unless they have some kind of stomach upset. For summer bees, this isn’t a problem as they can leave the hive to do their business most days – but winter bees face a challenge: the weather must be both warm enough and dry enough for them to be able to fly. If a honeybee’s body temperature drops below 7°C they become paralysed and many insects struggle flying in the rain as the raindrops can literally knock them out of the air. This can result in the winter honeybees being unable to relieve themselves for weeks at a time, so how do they do it? To put it bluntly, they store their fecal matter in their rectum for as long as they can! Their rectum expands to hold all the waste and can end up filling most of their abdomens, pushing their other organs out of the way until they can finally relieve themselves. On those rare late winter/early spring days when the sun comes out and the temperature briefly rises, many of the bees will go on what we delicately call ‘cleansing flights’ to relieve themselves. You may have spotted traces of this if you’ve made the mistake of putting washing out on these days, or recently cleaned your car! They’re small yellow spots that are often quite hard to remove. In fact, bee poo is even suspected of causing an international incident in 1981 when the USA accused the Soviet Union of chemical warfare when ‘yellow rain’ was supposedly released in Cambodia and Vietnam. Testing showed the substance to mainly consist of a mix of pollen grains, as you’d expect to find from bee faeces, and the pollen was from plants local to the area!

Bees clustering on beekeeper Damson for warmth during a winter hive check.