This year has been among the hottest years on Earth, July being no joke. With the unusually high UV radiation coming from the sun and incoming heat waves, one can really feel the sting of summer on their skin. Speaking of stings, how are the bees staying cool this summer?
We know that bees naturally vent hot air out of their beehive, and cool it down by fanning their wings. An individual healthy hive is comprised of tens of thousands of bees, all working together to maintain the colony's core temperature. Whether fanning to cool down during the summer or clustering to stay warm during the winter, bees are always toying with the thermostat to their internal HVAC system.
This has me wondering: how hot is a bee?
Hot or not?
We can calculate the amount of heat a single bee exerts based on how many bees are in a hive and the volume of the hive. Making lots of assumptions, we can now cross the t’s here, dot the i’s there, take the derivative of temperature with respect to the volume, compute gas laws, et voila! We find that each bee is between 30-38 degrees C (or you can just read this paper).
Of course, my estimate is very rough, and the paper goes into more in depth methods on how they found those numbers. Not all bees are created equal, in fact; some bees contribute more, and some less with a variation of up to 12 degrees.
Bees are known for their complex ecosystem and efficient task delegation. A honeybee colony is a uniquely selfless community known as a "superorganism". Rather than trying to complete a diverse range of tasks individually, bees realized they can be better off by dividing the workload and specializing in certain tasks. Part of this ecosystem is something I find absolutely astonishing: Heater bees, a sub-caste of nurse bees with abnormally high body temperature that strategically maneuver about the hive.
These wireless space heaters aren't just for comfort—their precision temperature control is important for raising brood. Brood frames that will produce foragers need to be kept at a slightly higher temperature than brood being raised for housekeeping tasks. These little ladies will even squeeze into empty forager brood cells to warm it up from the inside, working as a radiator of sorts (minus the coolant flush). How neat is that?
I'm always fascinated by all the quirks and factoids there are to learn about bees. Even one small area of research—hive temperature regulation--has produced so many revelations about how a hive works. But revelations also lead to more questions, such as why does hive temperature drop when a colony becomes queenless? A great question for a future post...