Dead hive autopsy

Unfortunately I have suffered my first winter losses in seven years with three hives although one was not dead but had a drone laying queen and a reasonable amount of bees left inside. This came as a bit of disappointment and you question your beekeeping skills but with my expanding hive numbers it was inevitable this may happen.

The first thing you do when you find a dead hive at one of your apiaries is to seal up the hive to prevent the other bees robbing the remaining honey stores and any potential spread of disease. You can then leave the hive to be dealt with at a later time if not possible to deal with it immediately.

So today I went to collect the two dead hives and deal with the drone laying queen and remove the hives. I removed the dead hives from the apiary and did a quick check next to my van to satisfy myself that it looks as though no notify able disease was the cause and load them into the van for further examination back at the shed and subsequent cleaning and sterilizing.

As for the drone laying hive I found removed the queen and sent her to queen heaven and then rightly or wrongly I moved a nuc that was weak onto the stand the DLQ hive was on and then shook the bees out of the DLQ hive in front of the nuc. The nuc was weak and the queen inside not marked and the queen that went into the winter was and rather old. Also the queen was not laying, could be down to bee numbers but I suspect a late supersedure and could prove to be another DLQ. It could back fire as the mass of bees entering the nuc could kill the queen but could also accept her and only time will tell if she has been accepted or if she is a mated queen and not a DLQ.

So it’s back to the shed for a more detailed examination of the hives to try and decipher what happened. This is important as it can only help with future beekeeping, what can I do to prevent it in the future, was it my mistake what signs did I miss or ignore, is it a coincidence that all three hives are from the same apiary or are they linked in some way are some of the questions detailed examination can possibly provide.

Hive one

First the DLQ as we already know what happened with this hive it’s still worth a detailed look and the tools for the job are hive tool, tweezers and optional disposable gloves. Just a quick note to say a queen mates with several drones on mating flights over a couple of days and the sperm she receives in this time is supposed to last all her life up to 5 years but typically a queen is replaced every three years. If she runs out of sperm at a time of year the bees are unable to replace her then she is unable to fertilise any eggs and unfertilised eggs produce drones whereas fertilised eggs produce worker bees. Another situation where a queen becomes a drone layer is if she is a new virgin queen and she has missed a window of about three weeks to fly and mate perhaps down to bad weather but she will eventually start to lay eggs regardless and they will be unfertilized and again only drones produced.

20150328_110633This is classic drone laying queen brood pattern. All uneven lumpy and bumpy and despite the gaps the brood is reasonably packed close together. As there are drones in the cells of worker brood and the drones are much larger the bees are forced to increase the height of the cells to accommodate the larger drone creating the bumpy surface.

20150328_110854So with the tweezers you uncap some of the brood and lift out the almost fully developed drones and larvae, what I am looking for is any kind of deformity and varroa. Although they are small drones (small because they have been raised in a smaller worker cell and not the larger drone cell) they and the white larvae seem to be clear of deformities and varroa.

20150328_111032On the other side of the frame two empty queen cells and they were not there the last time I looked end of last year. Two possibilities the hive swarmed late last year, unlikely in my opinion as it was a relatively small colony and its only two queen cells and you would expect more with swarming. Second possibility, although low down on the frame it’s a late supersedure and an unsuccessful or no mating resulting in the DLQ.  Either way it suggests a new queen and she was unable to get out and mate or mated so poorly she soon became a drone layer. The old queen was not marked in this hive and had I marked her then I would have known by looking at the new unmarked queen she was new but not ruling out the possibility the mark can sometimes rub off a queen.

Hive two

Overwintered on double brood and requeend with a rather expensive UK reared buckfast queen last July.

20150328_111637Very few bees left in the hive and this frame has a very small patch of raised cells and clearly a small drone sticking its dead out of a cell suggesting a queen problem.

20150328_111920On closer examination of the drones they clearly show deformed wings and has to be deformed wing virus

20150328_112015This frame has the sad tiny cluster of dead worker bees and again a scattering of raised cells indicating drone brood where there should not be any.

20150328_112431Into the lower brood box and this frame has both drone and worker comb on it and again both are occupied with drone brood.

20150328_113131Looking at the floor there is a reasonable carpet of dead worker bees, healthy full size drones, small stunted drones and ejected deformed bees that the bees were attempting to remove from the hive as the bees desperately tried to clean the hive.

20150328_113013Here we have one healthy drone one stunted drone and two badly deformed ejected immature stunted drones.

So this hive clearly had a varroa problem and a bad case of deformed wing virus. It also would seem to have suffered a queen failure, perhaps as a result of a virus or just bad luck who knows but as there was no evidence of a queen and queen cells the light scattering of drone brood and not concentrated in one area could be down to laying workers? If the drone brood is down to laying workers then this hive could have suffered a queen failure and Q- for some time and perhaps should have been picked up by me or she was a poorly mated queen and I was unlucky?

Hive three

This hive overwintered on single brood and a super of stores under.

20150328_113518This time a few capped worker brood where it’s supposed to be in worker comb but on closer examination out of the seven bees pulled from the cells six have deformed wings confirming another varroa problem.

20150328_113832There are very few bees left in this hive and this is the greatest concentration in the whole hive.

20150328_114030Moving down into the super its clear there is evidence of robbing and may account of why I have seen bees flying from this hive on days the bees were flying. The wax has been torn down to get to the stores by the robbing bees.

20150328_114136This has surprised me it would indicate a mouse but the hive has always had a mouse guard fitted I don’t know if the bees could or would do this, very strange.

This hive clearly had a high varroa load and suffered a bad case of deformed wing virus. If there were any bees alive in the hive when it was been robed out then I suspect they left the hive with the robbing bees and could account for the lack of bees in the hive.

20150328_114609The two dead hives both had some evidence of staining with bee poo on the underside of the crown boards and although I would expect sick stressed bees in the winter to carry nosema I thought I would scrape some off and run a quick test.

20150328_174354_Richtone(HDR)

2015-03-29 13.23.45Some of the poo mixed with a few drops of water and the results under 400x magnification and you can see what look like small slightly illuminated grains of rice and they are the nosema spores. There are two types of nosema, cerana and apis. With apis you get the typical stained poo marks inside the hive and is very common. With cerana you don’t get the obvious staining and its harder to detect it can also affect the queens and cause them to stop laying or even die. It is very difficult under a microscope at 400x magnification to tell the two types of nosema apart as the two spores are slightly different shapes and you need a much more powerful microscope to do that but it shows nosema was present.

20150328_173039 One thing I was very surprised at was the amount of pollen grains in the sample and way more than I have seen before. I was so surprised I did a 2nd slide and equally as many and have never seen this many before. It must have something to do with the bees overwintering and been unable to fly to relieve themselves until the sickness makes them go in the hive.

20150328_120858Ok after all this all that there is to do is to stack the hives and make sure they are bee tight and mouse proof and move onto a big wax recovery, cleaning and scorching so it all can go back into use nice and clean.

So following this I need to look at my varroa management and take a close look at all my hives to see if they are carrying to many varroa, take a close look at this apiary and test all the hives for nosema and perhaps as a matter of best play safe than sorry look at a complete equipment and frame change on the remaining five hives.

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6 Responses to Dead hive autopsy

  1. MerryBee says:

    I’m very sorry to hear of your dead hives, Thomas. I send a big thank you for taking the time to post your photos and analysis. As a new beekeeper I still have a lot to learn and I have found your analysis of the problems very interesting and informative.

  2. Emily Scott says:

    Sorry to hear this Tom. You have done well not losing any up to now, especially as you have a lot of hives. Unlucky to lose the Buckfast queen too 😦 I haven’t lost any before either yet but think that will change this year.

    • It’s my first in seven years Emma and always thought I was going to run out of luck one day. One of the dead colonies had queen problems but both had clear sign of varroa problems and that’s down to me. You have to learn from it and try to improve. With luck I can get round the few hives I am yet to inspect tomorrow including the allotment at Ealing and then make a plan. I think late April early May could be a busy time.

  3. Pingback: A beekeeper’s notes for April | Miss Apis Mellifera

  4. Brendan says:

    Thank you for taking the time to post this.

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