They're dead!

[gavin]

OK, I lost one. Two in fact. This one was the second to go, after the oxalic acid treatment if I remember correctly. I was intending to turn this into a blog item on diagnosing winter losses, but maybe it will be more fun to turn this open for all to comment here.

Background: one of two nucs from last summer that never built up properly. It remained a small colony at the end of the season, and was taking thymolated syrup but hadn't sealed all of it, although the stuff in open cells still mostly looked and smelled fresh.

No mice in this one, no dysentery outside:

dead_hive..jpg

Dead bees in a cluster near the tops of the spaces:

seams..jpg

Cluster with perforated cappings away from the cluster:

cluster..jpg

Perforated cappings mostly with adults ready to hatch, some chalkbrood, one slimy larva, a few loose scale (perhaps you can see one in the bottom left, second bottom row, five cells along)

perforations..jpg

On one comb face, stores immediately adjacent to the cluster:

stores..jpg

... and to finish off, it was repeatedly examined by me for foulbrood through the summer and early autumn, and carefully checked in August by the bee inspectors too.

Any views?

Gavin

[Jon]

It's hard to say what happened there.
It doesn't look like starvation or isolation starvation.
The cluster is very small and may not have been viable. Didn't you have temperatures down to -10 or worse?
There looks to be a lot of space relative to the size of the cluster.
They look like they died quite a while ago. What date did you do the Oxalic? Some people have suggested that Oxalic can deliver the coup de grace to bees that are already sickly from something like Nosema.
What on earth were they doing with brood in the winter?
What was the history of the varroa treatment and how many mites dropped?
Some of the bees look to have K-wing which is thought to be associated with acarine/tracheal mites .
Were there any crawlers in front of the hive at any point?
Acarine can shorten the life of winter bees.

http://www.edinburghbeekeepers.org.u...s/Acarine1.pdf

I would fumigate the comb with 80% acetic acid to get rid of any nosema spores which may or may not be there.
It always makes me nervous when I see perforated cappings but it is generally chalk brood or varroa damage.
if the colony was inspected various times the chance of AFB or EFB must be minimal.

[beeanne]

It's hard to say what happened there.
Some of the bees look to have K-wing ....

Can you direct me to which ones look like they might have K-wing? I've not seen it. Thanks.

[Jon]

In the 3rd, photo in the series, below and to the left of the cluster, there is a bee with the pair of wings apart.

There is a diagram and an explanation in this reference.

http://www.kysu.edu/NR/rdonlyres/8F2...achealmite.pdf

It's very hard to say why some colonies die.
Wing damage is also associated with varroa.

Gavin mentioned that it never built up properly to it was maybe carrying a problem since earlier in the year.

[gavin]

It's hard to say what happened there.

I agree.

It doesn't look like starvation or isolation starvation.

I agree!

The cluster is very small and may not have been viable. Didn't you have temperatures down to -10 or worse?
There looks to be a lot of space relative to the size of the cluster.

Correct. Are we going to agree on everything?! It never built up properly, which might mean an inherent problem (such as a poorly mated queen) or it could have just been the summer. And I'm not good at closing down the space (note to self: must make some polystyrene dummies).

Some people have suggested that Oxalic can deliver the coup de grace to bees that are already sickly from something like Nosema.
What on earth were they doing with brood in the winter?

Yes, could have been the oxalic that finished off a colony in serious trouble. Possibly just finished them off a little early - they may have been doomed anyway. Brood in winter? I suspect that they were making a stab at raising late-season brood on the ivy and on that syrup, then the cold caused the cluster to contract before the last bees hatched out. The capped brood have probably been there like that since Oct or so.

What was the history of the varroa treatment and how many mites dropped?

Apiguard from August (can't remember exactly when as Nellie's database isn't ready yet!) and oxalic in December 2008. Didn't count them, but I have been testing neighbouring colonies for Varroa tolerance so they could have been Varroa-stressed. However all my bees have been weather-stressed too.

Some of the bees look to have K-wing which is thought to be associated with acarine/tracheal mites .
Were there any crawlers in front of the hive at any point?
Acarine can shorten the life of winter bees.

Excellent! Well spotted. I had seen the bees with wings at funny angles but the penny never dropped. I hang my head in shame. Next chance I'll be back out to recover some of the fresher-looking bees for a post-mortem which entails ripping off the top segment of the thorax (scalpel under the first pair of legs and push upwards) and looking under a low power microscope for darkened rather than white tracheal tubes in the exposed body cavity. Didn't notice any crawlers.

I would fumigate the comb with 80% acetic acid to get rid of any nosema spores which may or may not be there.

I'm planning to burn the combs with solid stuff attached, and acetic acid fumigate the dry comb. It should deal with EFB if there is any and viruses too.

It always makes me nervous when I see perforated cappings but it is generally chalk brood or varroa damage.
if the colony was inspected various times the chance of AFB or EFB must be minimal.

AFB was 1 km away and the apiary was heavily infected. EFB was 2 km away in spring, also a fair amount of infection, but the perforations were over mature pupae and chalkbrood .... plus one slimy brown larva. And there were definitely loose brown scales in a few open cells, yet I'm moderately relaxed about this. Why?

G.

[gavin]

Anne, Jon

A close-up of some k-wing bees from this colony:

k_wing..jpg

[beeanne]

Thanks for the K-Wing pointer and references, I'd've not spotted it - but next time, you never know!
I thought that AFB scales were too difficult for bees to remove, in the bottom corner of the cell, yet you describe them as "loose brown scales"... so does that mean not AFB? Also, would the gungy rotting larvae be brown rather than being whiteish? Maybe the larvae died and bacteria then moved in -just decomposing rather than foul brood...? They look a bit like they all died at the same time, rather than the same point in development, so more likely to be chilled....perhaps. OK, shoot me down in flames gently!

[gavin]

Hi Anne

Take a bow! The level of knowledge these days of beekeepers not even a year in just amazes me!

Yup, brown due to later bacteria more than likely. The loose scale might be EFB (as could the mushy larva in a sealed cell) but there was quite a bit of sac brood in the apiary, more than I've ever seen before. This is a virus and gives mushy larvae, drying to a loose scale in opened cells. Fresh sac brood has a characteristic brown finger pointing at you in opened cells. This wasn't fresh.

So I'm assuming that acetic acid fumigation of clean comb will deal with this and also with EFB if there was any there.

Yes, the dead bees in the cells are all at the same stage. Perhaps because of synchronous egg laying in the comb, or maybe it is just that the emergence stage is the one where they are particularly sensitive to chilling.

Gavin

[beeanne]

Will scurry off and find out about sac brood now....

Edited to add: next time do not google sacbrood whilst having lunch.

[gavin]

I could have saved you the bother ....

sac_brood..jpg

From a couple of hives along. A cell with an odd capping, opened up for inspection.

Enjoy your lunch tomorrow!

G.