Anatomy of a dead colony

[Jon]

I have a few pictures of a colony which recently succumbed.
The previous fortnight had been cold with maximums of 5c or 6c

This was what I found, small cluster with the marked queen present. This was a 2011 queen. There was a similar sized cluster on the other side and another similar cluster on the adjacent frame.
failed-colony-queen-present.jpg

When the bees were shaken off the comb there were very obvious signs of isolation starvation. recently uncapped empty honey storage cells and brood present
failed-colony-isolation-starvation.jpg

There were stores present, but not right beside the cluster
failed-colony-brood-queen-stores-present.jpg

This was the problem, brood still present and the cluster would not leave it.
failed-colony-brood-present.jpg

Close up of the brood. the brood looks a bit ropey but had been dead for a while probably due to chilling and the bees had started to tidy up.
failed-colony-brood-close-up.jpg

[Jon]

So what happened?

Fortunately I have fairly good records for this one.
the queen was a 2011 daughter of a Galtee

col82.jpg

It was a strong colony which I used as a cell raiser for most of the summer.
I grafted a few from this queen as well
It was one of the ones Meg Seymour the bee inspector checked for foulbrood and other lurgies on 26th May and it got a clean bill of health.
You can see in the first photo that it had a load of drones and at this point the colony had 10 frames of brood.

uncapping-drone-brood.jpg meg-grafts2.jpg

I took a couple of frames of brood from it in August to make up a nuc which in hindsight was probably not a good idea.
By the end of August I had noted that it only had 3 frames of brood and had weakened a lot

I started Apiguard treatment on 30th August.
This one got no syrup but was given a slab of fondant at the end of September by which time it had weakened and was reduced to 5 frames.

On 20th October I made a note that it was probably too weak to overwinter successfully.

There were still signs of life On December 1st but when I was applying oxalic to the colonies in this apiary on 16th December I found the scene in the pictures above.

The colony was just too small and died of a combination of freezing and isolation starvation.
There were very few bees on the floor and probably no more than about 1500 in total.
failed-colony-dead-bees-on-floor.jpg

The signs point to a failing queen.
The brood pattern does not look great and it was a sign of desperation that the colony was still trying to make bees in December when the queen should have shut down.
The colony was first noted to be weakening fast in August and there was a steady decline from that point.
Extra feeding may have helped as September was a very wet month here and the bees had little chance to forage.

[gavin]

Excellent review. Maybe more of us can put up images of our lost colonies and everyone can learn.

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[Mellifera Crofter]

...
There were stores present, but not right beside the cluster
...

And now a sad story, Jon.
They were clustered to the side, it seems. Did they have candy right above their heads on that spot?
Kitta

[Beefever]

I was wondering if it is still possible to test the remains of the colony for nosema. The bad weather and stress of continuous queen rearing could have taken its toll.
I’m not a fan of Apiguard (although I do use it) as it seems to put my queens off laying for a month just at the time the colonies need to prepare a good population of winter bees and seems to demoralise them, somehow, so they don’t recover before winter.
Just a thought.

[Ruary]

I was wondering if it is still possible to test the remains of the colony for nosema. .

Quick answer is yes for nosema, no for acarine. We have used dessicated bees several years old to demonstrate nosema spores, and I sent Randy Oliver some which were over ten year old for him to use. They were able to PCR it and determine that they were nosema apis.

[Jon]

Did they have candy right above their heads on that spot?

They did- but fondant is not a lot of good in really cold weather which lasts for several days as they need liquid stores.
This is especially true with a small cluster which cannot generate heat.

I’m not a fan of Apiguard (although I do use it) as it seems to put my queens off laying for a month just at the time the colonies need to prepare a good population of winter bees and seems to demoralise them, somehow, so they don’t recover before winter.

I used Apiguard on 37 colonies this year. It can put queens off lay but the advantages outweigh the disadvantages.
The bees in that colony would barely have covered 1 side of a frame. That is definitely not enough to overwinter. It might have had a chance in a double Apidea.

Bear in mind that a 'normal' rate of winter losses is historically 10%-15% so out of 37 you might expect to lose 4 or 5.
The clusters are smaller this year. I measured 10 on my allotment site and the total number of seams was 46 whereas this time last year it was 67. On that basis losses could be a little higher than usual.

Re nosema, spores are pretty much present all the time but it is the number of spores present in a bee which leads to problems.
In that Yucel paper I am always citing he defined low infestation as 0.1-5 million spores per bee, medium infestation, 5-10 million spores per bee, and high infestation more than 10.1 million spores per bee.
Also, there was no sign of streaking in that colony although with N Ceranae that would not be an indicator.
I can't tell for sure why it started to dwindle in the first place but at the end it was just too small to generate hear and move to stores.

The bad weather and stress of continuous queen rearing could have taken its toll.

This one was pushed a lot as it was raising cells for about 3 months.