Bee line from Virginia

Question: When is a beehive hairy? Answer: When it grows a beard.

A poor joke but it helps to kick-start a post about heating and air-conditioning.

For most of the year, worker bees struggle to maintain the brood chamber in the 90 degree Fahrenheit range (32-35°C) needed for larvae and pupae to thrive in the comb. “Heater bees” keep the hive warm by vibrating their body and wings, which needs energy from honey delivered by other workers. In cold winters, the queen bee stops laying eggs and the hive switches to survival mode by clustering around her in a tight ball to avoid freezing to death. If a tele-thermometer is inserted deep inside the brood chamber you can monitor beehive breeding activity because the temperature rises to a stable level when she starts laying again in milder weather.

Bearded hives

Bearded hives

Recent hot weather in the Virginia Peninsular posed the opposite challenge – heat stress. Daytime temperatures peak around 100° (38°C) and the nights stay warm. At such times the brood can perish and their wax cells soften and start to melt. Beekeepers help their colonies to get through the ordeal in July and August by painting their hives white and propping open the top outer cover to encourage a flow of air, but the workers carry a larger share of the effort to keep cool.

If you see lots of bees collecting water from puddles or swimming pools you know they are hot. So intent are they that it’s hard to discourage the industry, but human swimmers have little to fear because they are rarely aggressive except when defending their hive (who can blame them?). They regurgitate water brought home, which evaporates more quickly in the draft created by “cooler bees” lining up to beat their wings near the entrance. Yet another amazing fact about bees.

Smuttynose brewery

Old geezers love beer

And bearding? I haven’t seen it in daytime, but when foragers come home after a hot day many of them stay at the hive entrance instead of going inside. It reduces the heat load on the brood. This behavior startled me the first time I shone a flashlight on a hive after dark. The crush of bees climbing over each other in slow motion had avoided taking their heat inside. They looked like a goatee, and the fuzz of brown hair on thousands of heads and thoraxes can fairly be called a beard. Docile and hard to provoke, they ignore nosy neighbors like me who wonder what is going on in their collective brain. I think they are like old geezers I know who love sitting on their porch with a cold beer on a sultry night.

Next Post: Science Flaw and Fraud

 

About Roger Gosden

I took early retirement from my post as Professor & Research Director in Reproductive Biology at Cornell Medical College in New York City to concentrate on writing about science and nature,
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