The weather has been warm and sunny for the last few days. Coincidentally, I’m also working fewer hours at my day job so I had an opportunity to check my hives yesterday. I’ve known for a few weeks that one of my hives died and that one was still alive. But yesterday I took the time to open up the dead hive to see what happened. Here is what I saw:
Before I explain the photo, I will describe how bees overwinter. Bees do not hibernate- they remain active all winter, eating honey to give them energy and shivering to stay warm. They form a tight ball, or cluster, to conserve heat. In the centre of the cluster the temperature is usually around 32C. Beekeepers often put insulation around the hives so the bees do not need to work as hard to stay warm and to protect from sudden swings in temperature. Bees can go a long time without defecating in the winter, but they need to take cleansing flights occassionally. Defecating in the hive is unsanitary and can spread diseases so honey bees will not do it unless something is wrong.
Successfully overwintering a hive is the most challenging part of beekeeping (in my opinion). If a colony is in tip-top shape, with plenty of bees, plenty of food, and no illnesses or weakened immune systems, and if the winter weather is favourable, a colony will live. If one or two of those variables are not optimal, the chances of a colony surviving winter are lessened.
And now to the photo. All those brown specks are bee poo, which should not be in the hive. You can see the remnants of the frozen cluster in the upper left, just beside the shadow. I didn’t take off the top box to look at the bottom one; the cluster may extend down and become larger. To my surprise, there was lots of honey still in the combs. I had assumed they had starved but apparently something else happened. There were also many dead bees immediately outside the hive. Figuring out what went wrong is a bit like a detective mystery.
My best guess is that the bees got dysentry. Dysentry is not a disease in itself, it is symptom. It simply means the bees got diarrhea because they were eating something that was hard for them to digest. The sugar syrup I fed them this fall to help them build up their winter food stores may have fermented, which can cause dysentry.
But that’s just a guess. I’m not really sure what happened. I was also surprised that there were so many bee parts, rather than whole dead bees. Maybe the bees were carrying dead bees out of the hive and in the process the bees were falling apart, being frozen and brittle. If anyone has any suggestions on what happened to my hive over the winter feel free to leave a comment.