Thermoregulation

Definition

Heating is by shivering: bees decouple the flight muscles from the wings and contract them, and heater bees press into empty cells among the brood to warm pupae directly. Cooling is by fanning and by evaporating water the foragers deliberately collect. In winter the colony stops heating the cavity and heats only the cluster, holding the centre near 20 °C while broodless.

Where the word gets used loosely

A pupa reared a fraction of a degree too cold becomes an adult with measurably impaired learning and dance performance, which is why the tolerance is so tight. It is also why bees at a pond in July are usually collecting water for cooling rather than drinking.

Bee records that discuss this

• Arctic bumblebeeThe northernmost bee in the world, nesting within a few hundred kilometres of the pole on Ellesmere Island and northern Greenland. It survives by being the most effective thermoregulator of any insect — a queen can hold her thorax above 30 °C in air near freezing — and by compressing a whole colony cycle into an Arctic summer of a few weeks.

Guide records that discuss this

• How bees regulate hive temperatureA honey bee colony holds its brood nest between 34 and 35 °C year-round, in climates ranging from Siberian winter to Australian summer. It does this with shivering, fanning and evaporative cooling, and the precision matters.