cluster

[cam bishop]

I saw the excerpt on your blog about clustering. I find that my bees are flying at 14°C - which I think converts to about 56°F. I wonder if this info is based on old information. I don't see clustering until the temp is around 45°F [7°C] I note that your bees in the BeeMax boxes don't appear clustered at even lower temps. I wonder if bees are more adapted to cold now than they were back then?

[Allen Dick]

The excerpt is referring to the air temperature around the cluster in absence of incoming heat from the sun or other sources.

Temperatures inside the hive at mid-day tend to be higher than air temperatures outside the hive, especially when the sun is shining on the hive and when the bees are active. Active bees can generate a lot of heat. (The mass of the honey and the insulation can result in the hive interior remaining cooler, too, on occasions where the outside temperatures rise suddenly since the mass is slow to change temperature.)

Insulated or EPS hives reduce heat loss, so the temperatures can be quite a bit higher than ambient, especially if there is no wind and the sun is shining on the hives.

Once warmed up, individual bees can maintain their body temperature above chill temperature when they fly out into weather considerably cooler than their chill point as long as they are healthy and have sufficient sugar in their stomach.

I see them flying out and back when it is right at the freezing point sometimes. If they stop and set down, though, they may cool enough that they cannot get going again unless it is sunny. Sunshine helps them keep warm. If you go out on a cold day and stand in the sun then go into the shade, you'll be surprised at the huge difference in comfort, even though the temperature of the air is the same.

As for the bees at the auger holes, they are in the exhaust draft from the cluster and have the advantage of that heat. They are also active, and that keeps them warm.

If you look at the pictures on the drop page, you'll note that the bees are, indeed, clustered, but there are always a few bees which are active if the weather is above freezing and there is any stimulation. This may be due to discomfort due to fecal pressure or other factors.