Bees in Winter
Posted on 20th December 2017 at 21:45
What do Honey bees do in the winter? It is a question I am often asked. Honeybees and Bumblebees over winter in different ways
So why do Honeybees and Bumblebees have different strategies to manage the winter in the northern hemisphere?
It is all to do with their life cycles. Bumblebees have an annual cycle where the Queen is "born" in the summer and builds herself up through the summer as part of a colony. After mating she finds a dry spot, underground, in a tree or in a loft space and hibernates, alone, until the spring. Hibernation is a condition where the bee becomes dormant. When conditions are right the Bumblebees break their hibernation. Bumblebees appear early in the year which is why they are usually the first flying insect you see in the Spring.
Honeybees have an altogether different life cycle. A Honeybees colony has a single Queen that may live for fours years. Given that is the case then the bees must have a mechanism to keep the queen alive through the winter months. Bees collect nectar from the flowers and turn it into Honey. One of the properties of honey is that it does not spoil so will keep for a long time. This is very useful adaptation as it allows the honeybees colony to build up a store of honey through the summer which they can eat through the winter.
As the autumn draws on the honeybees "born" in that period are bigger and stronger than the sisters from the summer. These bees need to be robust as they are going to live throughout the winter and into the spring. The summer bees die off leaving about 8,000 to 10,000 winter bees. As the temperature drops, especially at night, the bees cluster together in a ball, the queen in their midst. Their close contact preserves their body heat. If it gets colder still they will vibrate their bodies to generate heat. There is a point where creating heat is not sustainable so they go into a state of diapause. This is a temporary state similar to hibernation where the metabolic processes shut down. However, as soon as conditions improve the bees become active again.
Honeybees cannot fly below about 10°c. Their flight muscle cannot generate the heat need to move their wings fast enough. About 5°c the bees become inactive but will have clustered by this time. Diapause is triggered at this lower temparture. Luckily for bees such is the composition of the haemolymph (bees version of blood) it does not freeze. When the temperature increases they are able to break diapause and go about their business.
Tagged as: Honeybee
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