The other day, when I was spying on the hive through the window, I noticed how warm the cluster of bees was through the glass. Bees gather together to keep warm and actively heat the hive and brood comb when it is cool out (they cool it too when it is hot). They need to keep the temperature "just so" for the larvae and pupae to develop. This morning I went out to replace the feeder and took my infrared thermometer with me. I usually use this to monitor the wood burning oven, but it comes in handy elsewhere too :-)
This was shooting the temp through the glass at the edge of the bee cluster, but there was quite a difference. The first measurement is on the other side of the follower board next to the feeder, where there were no bees. The second was on the bee cluster itself. It is probably hotter still deeper in the bee cluster, but even with this we can see how warm they get. The outside temperature was about 32*F at the time. The bees heat up by vibrating their flight muscles in the thorax (which is where most of that sugar is going!). I also noticed the other day that Christy at
Gold Star Honeybees had linked to a great video on
"heater bees" where researchers had actually used infrared cameras to capture the process. Check out the video.
Bee-wise, not a lot of change here. We have had another bout of colder weather - down to freezing. This has limited the bees activity and I noticed they have started hitting the feeder again (gotta stay warm). Today should be warmer and sunny so they should be getting out. As for the temperature, the bees should be able to handle it, but I am anxious about the trees (plum, apple and pear) as they are just about to break out in bloom. It is not unusual to have the crop freeze out at blossom and I'd really like to have those available for the Apis clan.