This article is intended to provoke comments. Please send in your thoughts if you think you see something we didn’t.
Gerard took some pictures of a neighbor’s hive which died this past winter. The owner said all appeared to be going well until mid-December, when the hive suddenly died. Also the beekeeper did NOT use any miticide. The hive had already been partially cleaned up prior to Gerard seeing it. Gerard then shared the pictures with two other beekeepers and together they tried to deduce what happened to the hive.
This first picture shows randomly distributed capped drone brood.
The second picture shows some bees head first into empty cells. (Remember the hive had been partially cleaned up. There may have been many more bees in this condition.) This close-up also shows what may be varroa poop (excrement) near the mouth of some cells. See the little white gobs on the cells walls.
Using these limited clues our trio of beekeepers have attempted to deduce what may have happened. Here is what they have postulated.
1) The randomly capped drone brood in the middle of the frame is usually a sign of laying workers. Laying worked usually emerge only after a few weeks of being queenless.
2) Then take into account the drone brood takes 3 1/2 weeks to mature and emerge. This means the hive was likely to have been queenless for a period of at least 6 weeks.
3) The loss of the queen would of itself cause the hive population to dwindle and die out during the winter.
4) A second possibility is that it could also have been a sick queen which began laying drones only and in a random pattern, but this considered less likely.
5) The "head first bees in cells" is not considered overly significant. When the bees are in cluster this is the position of many of the bees when they are in tight cluster. They occupy the cells in order to maximize the bee density to conserve heat.
6) The presence of the varroa poop is not surprising. All hives have varroa mites in them. We also know deformed wing virus (DWV) is carried by varroa. The sigificance here is that the cell cleaner bees have not removed it. Unfortunately the hive was cleaned prior to Gerard seeing it, so he could not look for K-wing or short abdomen worker bees which are characteristic of DWV.
Our 3 man team is divided between queenlessness and varroa/DWV as the root cause of the hive’s death.
So what do you think killed this hive? Please post your thoughts in the comments section.
Another interesting observation. This beekeeper lost 2 of 3 hives. The living hive is next to a planting of hops. There was some speculation the hops may have been controlling the varroa. If you are not aware, Hopguard miticide is derived from hops. Discounting this theory is the fact that one of the deceased hives is located only 200 yards away. It also should have received the benefit of the hops.