A grimy aspect of beekeeping
As I wrote last month
Last month, while writing a piece for this journal entitled “The Quiet Winter Season,” I stated, “Good luck is also a vital component of successfully wintering bee colonies.” Not one of you needs to be told that all luck is not good. In many ways, bad luck is harshly educational, but even so, clearing and refurbishing dead colonies is a grimy job. Winter-killed beehives are certainly examples of colonies — and beekeepers — experiencing bad luck.
The occurrence of occasional colony deaths — at any time of the year — is a beekeeping fact of life. In total, the possible reasons for these seasonal die-offs would require too long of a discussion. Indeed, reasons for some colony deaths may never even be known, but I do know this fact: I never enjoy dealing with deadouts. It’s a messy job, but it’s a task all beekeepers will have to do at some point.
Enter the beekeeper
As I discussed last month, at the most fundamental winter preparation level, all that any beekeeper is trying to accomplish is to help address these wintering problems or ameliorate the winter challenges that a colony faces. We provide housing, food, protection from the elements, and we try to help them stay healthy by using chemical or behavioral means. Sometimes, both beekeepers and their bees fail. Make no mistake — it’s not always easy out there for a beekeeper and their bees.
Anticipate it — sometimes colonies die
While I do the best I can to forestall any colony’s death, when one goes, I can, at least, truthfully tell myself that the colony would not have fared much better on its own. The beekeeper’s prime winter goal is to address as many challenges as possible, and then wish the bees good luck. We hope that most — if not all — will survive the season. Sometimes they don’t. What then?
The dead colony’s autopsy
Diseases and pests
Obviously, the first concern when autopsying winterkilled equipment is to determine what caused the colony to die. A primary concern is that spore-forming American foulbrood (AFB) may have been the problem. This is a scary, but rare occurrence. If AFB has been a problem in the past in your colonies, contact the state apiary inspector and have an assessment made.
At times, nosema is a problem. Unfortunately, nosema is difficult to diagnose, and the only treatment procedure, applications of fumagillin, is somewhat uncertain.1 Increasingly, nosema treatment is simply queen replacement.2 Excessive defecation spotting is an indication of this type of dysentery, but a microscopic examination of fecal material will be required to confidently determine that this disease caused the issue.
All honey bee diarrhea is not nosema. Many years ago I had a colony that appeared to have a terminal nosema infection. I was working at a university and was able to determine that the colony was dying due to wintering honey stores having a high melezitose content. Somewhere my bees had found this nonreducing trisaccharide sugar that was produced by unknown plant sap-eating insects. Quite likely it was produced by aphids but superficially, the symptoms looked like nosema to me. It resulted in a seriously soiled colony.
It’s probably just me …
Is it just me or have incidences of extreme dysentery declined in past years? Yes, I do commonly see dysenteric indicators in some of my colonies, but not like the raging outbreaks in the photo below. What happened?
It’s not only extreme dysentery declining that I have noted. In my earliest beekeeping years, European foulbrood (EFB) was disappointingly common. Then, in my personal bee world, it simply vanished for about 25 years. Without warning, two years ago, I had two cases of EFB in my hives. Where did it go and why did it return? What happened?
Are tracheal mites still out there? They were the beekeeping boogieman for a while, but now I don’t read much about them. Apparently, some varroa controls also destroy tracheal mites. Is that what happened to them?
There are always mites in the management mix. Varroa, and the viruses it vectors, are probably the most serious wintering problems that a colony faces. It appears that even a small population of varroa mites can vector viruses that are able to kill or maim bees on their own.
As scientists and beekeepers grow in their understanding of the full effects of these viral invaders, our respect for the damage that they cause is increasing. At this point in our hive management recommendations, our best control of invasive viruses is to vigorously suppress varroa populations. A hive killed by mites can be safely reused.
(But stay tuned. While this looks like a solid recommendation at this time, in the future, new information about bee viruses and other microscopic invaders might change this belief. Presently, I have no scientific documentation to suggest that this is happening so I will continue to use restored equipment. I am only suggesting that we stay alert.)
In warm climates, the wax moth is a relentless taskmaster. The combs are often under attack before the colony is even completely dead. Warm-climate beekeepers must be doubly alert or their problem is compounded — they will have lost bees and comb. In cooler climates, the wax moth situation is still a concern, but not as urgent.
Keep mice out of stored equipment containing stored combs. Mice are attracted to dead bees in the combs as a food source and will make a bad situation even worse.
Starvation has distinct characteristics. The cluster will be in a tight (and dead) group, probably near the center of the colony with single dead bees scattered about. Frequently, the dead cluster is right at the top of the colony. (See earlier photo.) Upon removing frames from the colony, many bees will be seen in cells with their heads toward the comb midrib. Meager amounts of honey, if any, are usually all that remain. Occasionally, patches of honey can be found scattered throughout the hive, but bees were unable to get to it before chilling.
To restore equipment — or not
Once the reason for the winterkill has been determined, you need to decide what to do with the equipment. Diseased equipment should be destroyed or sterilized depending on the disease pathogen. Colonies that starved should have dead bees shaken from the equipment and comb as much as possible. True, replacement bees will remove all the dead bees from the frames, but assisting the bees with the task can save critical time for the developing colony.
Even after most of the dead bees are removed, a stench will be noticeable and unpleasant. Many bees will have filled wax cells with their bodies. If the humidity is high, their dead bodies may become …