Honeybees (Apis mellifera) are social insects belonging to the hymenopteran family. Originally from Asia, they have been introduced to all continents except Antarctica through domestication. These honeybees are small, hairy insects with six legs (used for collecting nectar from flowers) and typically have striped abdomens. They also possess four membranous wings and a mouth equipped with mandibles, which can be used for grinding or licking.
They live in colonies, with some colonies reaching 50,000 to 80,000 individuals before swarming. These colonies are highly structured, centered around a unique queen. The two other castes in this community are the worker bees and the drones (males responsible for fertilizing the queen).
Honeybees can be found in the wild or in hives maintained by beekeepers. They are incredibly valuable because they play a vital role in pollinating flowering plants, contributing to their reproduction and overall sustainability. Nearly 80% of plant species rely on this pollination.
The worker bees are divided into several categories: Nurses, Indoor workers, and Foragers.
What Happens to Honeybees in the Winter?
During the winter, the hive is no longer as active as in the spring or summer. It operates at a slower pace due to the lack of flowers to forage, dwindling food supplies, and cold temperatures. Honeybees hunker down in the hive to survive. The queen lays fewer eggs, around a hundred per day, compared to as many as 2,000 in the summer.
During this winter period, they undergo a form of hibernation, reducing their body temperature and slowing their metabolism. These pollinators are a form of hibernation, but not true hibernation. The bees’ work during this time is to maintain a specific temperature (30°C) inside the hive to ensure the colony’s survival. To generate heat, they contract their flight muscles without actually flapping their wings. To withstand the dropping temperatures, they seal any gaps with propolis to insulate the hive from cold, humidity, and parasites.
Below 10°C (50 °F), the bees cluster together, forming a ball to resist the cold. The cluster moves around in the hive, where there is honey in the frames, within reach of their mouths.
Without brood (made up of eggs, nymphs and legless larvae) inside the hive, bees can survive temperatures as low as 13°C. However, when the temperature drops to 7°C, the bees die.
Honeybees do not hibernate in the same way some animals do. Instead, they enter a state of reduced activity, clustering together to maintain warmth and consuming stored honey for sustenance.
How Do Bees Feed in Winter?
Domesticated honeybees don’t enter deep lethargy like hibernating animals. They remain active to maintain the optimal temperature inside the hive. Their activity is reduced, as are their energy expenditures, but they need to feed daily to avoid starvation.
They consume their stored honey reserves, collected before the winter period, within the hive. The colony’s survival depends on the quantity of these reserves. If the reserves are insufficient, the bees won’t make it until spring and will die of hunger.
To reduce the number of individuals to feed, domesticated bees expel drones from the hive before winter. Drones are no longer needed during this season as their primary role is to fertilize the queen.
In preparation for winter, honeybee colonies often eject or eliminate drones (male bees) since they are no longer needed for mating. This is a survival strategy to conserve resources during the colder months.
What Do Beekeepers Do in the Winter?
Beekeepers prepare their hives for winter in advance, typically in late September or early October. The first operation, after harvesting honey, is to treat the hives for the Varroa mite (Varroa destructor), a common parasite among bees. Then, they insulate the hive by placing polystyrene on the frames and adding a plastic bottom to the ventilation grid at the hive’s base. This intervention aids in maintaining the hive’s temperature while allowing bees to leave through the hive entrance.
Beekeepers also reduce the number of frames in the hive. For instance, in a hive with 10 frames, they might leave 6 for the winter and remove the other 4 frames that are considered unnecessary, either due to low food reserves or being empty. As the queen lays fewer eggs during this period, she’ll require fewer frames.
They also reduce the hive’s internal space by using partitions to cluster the colony. These partitions are made of polystyrene covered with aluminum foil to reflect the heat generated by the bees. Beekeepers assess the necessary space according to the colony’s size.
The winter cluster is a tight group of honeybees that forms within the hive during cold weather. Bees on the outer layer insulate the cluster, while those on the inside generate heat by shivering.
During the hive’s winter preparation phase, beekeepers weigh the hive to ensure there is enough food for the bees to survive the winter without issues. On average, a 10-frame hive should weigh between 35 and 40 kg before winter. If it weighs less, the beekeeper will need to feed the bees with syrup (made of water and sugar) when the temperature reaches 15°C. Bees will lower the syrup into the frames to supplement their initial honey reserves.
As temperatures drop, beekeepers provide solid food known as “candy.” This consists of glucose, often from sugar beets. It can be purchased or prepared by beekeepers using sugar and water. Some add aromatic plants like thyme or lavender. Beekeepers use a feeder to provide this candy to their bees, positioning it above the frames inside the hive. The candy is consumed directly by the insects.
Below 15°C or 10°C, beekeepers refrain from opening the hive to avoid endangering the bees. They also avoid moving the hive because the cluster could break and fall to the bottom of the hive. Bees, sluggish from the cold, may lack the strength to regroup and could die. The same is true in the wild; if an animal like a woodpecker or a tit disturbs the cluster, it might fall to the ground.