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.
Pingback: The Dead Hive Mystery, Part 2. | The Beanstalk
I’m curious about this. I’d like to run it by my Uncle (30 years beekeeping). A question that pops into my head probably doesn’t apply with that nice styrofoam insulation: were any exits blocked? I’m accustomed to the fat old blanket wraps where you have to line up the holes/exits fairly well. Of course, some hives get absolutely buried in snow depending on the yard layout, and when they’re dug out there is a lineup for the potty.
I had two exits, one at the bottom with an entrance reducer, and one about an inch wide at the top of the styrofoam. The bottom exit froze over at some point in the winter, I guess when the cluster dwindled to a size where they were generating enough heat to melt the snow but not enough to melt a ‘chimney’ through the snow the way the other hive did. Did you read the following post? I think I may have had a queen problem, but that’s just a guess too.
I did read the follow-up post, and anticipated putting my follow-up comment there. 🙂 You provide a lot of clues, although knowing the condition of the hive going into winter, when it was wrapped, such as what shape and position the cluster was in (perhaps it was already becoming separated), might have foretold problems. I’ll let you know if I find out any other quality ideas. I like this detective work! Good thing, as I get into bees in fall or spring…