When the bee contracts its wing musculature isometrically, what temperature can its thorax reach?
- About 35 °C.
- More than 40 °C.
- About 20 °C.
Show answer
Correct answer: 2.
More than 40 °C.
Why?
The bee can produce heat by contracting its wing muscles without beating its wings. This is referred to as an isometric contraction: the muscles work, but there is no visible movement of the wings.
This heat production is concentrated in the thorax, where the powerful flight muscles are located. Locally, the thoracic temperature can exceed 40 °C.
This mechanism allows the bee in particular to warm up its muscles before flight in cool weather, or to contribute to the thermoregulation of the brood in the colony.
What to understand
A bee does not fly efficiently with thoracic muscles that are too cold. Before taking off, it can therefore produce heat by activating its wing musculature.
In the hive, certain bees can also act as “heater bees”. They produce heat with their thorax and transmit it to the brood or to the neighbouring cells.
This local temperature of the thorax must not be confused with the average temperature of the hive or of the whole colony. The thermoregulation of bees is at once individual and collective.
Key points
The wing musculature of the bee can produce heat without visible movement of the wings.
The thorax can locally exceed 40 °C during this active heat production.
This mechanism plays an important role for flight in cool weather and for the thermoregulation of the brood.
Further reading
► Understanding the flight of the bee
► Sense and nonsense of thermal insulation of hives