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Analysis of a Dead Out

Analysis of a Deadout


Jeff Gabric

I had this one dead out that I basically watched die and I decided to do a post mortem analysis.  It was January until I got into my dead out.  I had known for a few weeks this wasn’t alive.  I clean out the dead bees and gathered up most of the dead bees which was about 4 ounces.  I estimate that I may have retrieved a portion of the bees and if we assume a lot were carried off in the final month there may have been a pound of bees.  A pound of bees should be about 3333 bees.  But I am going to go further with this assumption and say that there were 10,000 bees in this colony this fall; just to be conservative and make the numbers work easier.  

If you look at the chart below it has the mite drops from the Oxalic Acid treatments that were counted each day on the pan in the screen bottom board.  The first treatment was October 23rd and 13 days later there was a second treatment.  The total drop was 3160 mites and if we assume that there were 10,000 bees in this colony then that is a 31.6% mite load.  That means one mite for every 3 bees.  We should get nervous when there is a 3 to 5% mite load.

The moral of the story is I needed to be on top of the mite loads earlier on the colony.  Much earlier.  By October it is too late to treat for mites.  Fall mite application may clean up your hives and help overwinter them, but primary mite treatments need to happen in July and August at the latest.

I counted out 100 bees and looked at each of their abdomens to find mites.  I found 6 mites which means that there was still a 6% mite load after the 3160 mites were removed with the Oxalic Acid treatments.  I also found some drones, a few small hive beetles and a lot of small bees that may have just emerged with deformed wing virus you can see in the upper left.  Tweezers, toothpicks and magnifying glasses help out in this endeavor.

Here was the final cluster and I counted about 200 bees head-in on this side and that many on the other side.  This was found in the top box with about 50 pounds of honey surrounding it.  It’s not that the starved.  When I took this photo, I had removed a lot of dead bees already.

I found about 3 frames with clusters of brood like this in the bottom box that had been abandoned.  There were some bees that were half emerged.

This photo was taken next to the final cluster.  If you look two photos up you will see the same thing but not as close up. The white grainy stuff in the bottom of the cells is varroa mite urine that has crystalized.  This was deposited under the capped brood and remains because the bees moved on and did not have a chance to clean the cells.  To me the shocking thing is this was in virtually every cell, which means there were mites in every cell and maybe more than one mite in each of these cells.

This photo I could see a varroa mite still stuck to the side of the cell wall.  Probably the mother female that never made it out of the brood cell.

Here is the mite drop chart. This was count on a daily basis.  Usually if you see a string of the same count then it may have been counted every second or 3rd day and then the number divided equally between the days.