Loss of Two Hive Apiary

[DonkeyDonz]

I had known something was amiss with my two hive apiary from earlier in the winter, and yesterday the bright, relatively warm weather allowed me to confirm any fears I had.

The apiary has been inactive with no food debri visible dropped through the open mesh floor onto the slabs below, no hum when the side/backs and front of the hives were tapped, no activity on warmer days in the supers visible through the polycarbonate crown boards.

Yesterday, I decided to investigate the brood boxes and, as I had expected and was prepared for, were small clusters of dead bees on comb, plenty of stores and noticeably tiny patches of unhatched brood.
I photographed the brood frames from both hives and then removed all frames from both colonies to find hundreds of dead bees on the open mesh floors. I took samples from both colonies.

I had treated both hives with Apiguard in late August/early September and both colonies were strong (one stronger than the other) and with both queens present. I did however notice that both hives had excessive stores in both brood boxes. The varroa treatment immediately followed harvest of excess stores. After treatment I added a rapid feeder of inverted syrup to build up both supers for the bees for winter.

Both hives are standard nationals on shallow brood frames.

The apiary is sited close to intensively managed farmland but with plenty of nectar/pollen available from the adjoining railway embankments. I have kept bees successfully on this site for seven years and had never lost overwintering colonies.

Judging by what I found yesterday, I can see both queens had failed/perished before laying the spring bees. I can't understand the mass die off. I can't imagine it's pesticide contamination as there were no bees dead outside the hives since autumn, when the last of the summer bees were dying off. I hadn't noticed any adverse behaviour at the front of the hives, and we had wheat here last year that the bees would have no interest in anyway.

I have attached photographs of what I found.

Is it advisable for me to send samples, as I'm keen to know what my bees perished from?

There was a hornets carcase along with the dead bees on the open mesh floor of hive two that I included with that sample.

 

[user 11159]

varroa maybe not enough or any winter bees .you can see mites on the dead bees ..

 

[DonkeyDonz]

varroa maybe not enough or any winter bees .you can see mites on the dead bees ..

I think both queens failed to lay winter bees. No varroa

 

[Erichalfbee]

I can see varroa on some of the dead bees on the frames. There are punctured cappings and some bees partially emerged with their proboscis extended. The bees have been dead for some time. I certainly think varroa played a part.

 

[Amari]

Your sad story and pics seem identical to mine posted a few days ago. My colony also had been treated - with Apivar as opposed to your Apiguard.
https://beekeepingforum.co.uk/threa...e-the-super-full-of-stores.56395/#post-893599

 

[Antipodes]

I can see varroa on some of the dead bees on the frames. There are punctured cappings and some bees partially emerged with their proboscis extended. The bees have been dead for some time. I certainly think varroa played a part.

Well spotted Dani.

 

[Swarm]

Just zoom in on the bees dead on the comb and the first thing you will see is mites.

 

[user 819]

Mass die off is because the bees were older later summer bees , the winter bees being laid up in Autumn likely not occurring in the numbers needed to survive the rigours of winter for which there are 6 or 7 weeks to go yet.
Mites can be seen on dead bees , perforated cappings all lead to varroa treatment not being too effective or the timing not correct.

From the pics supplied there are very scant stores to be seen.

 

[Eyeman]

Strong colonies high mite numbers poor response to varroa treatment. Most of us can’t be bothered to check mite numbers after treatment to make sure the treatment worked.

 

[Zaclangley]

It seems possible that depending on the timing Apiguard alone may not have been enough this year. Not sure if it was the temperature at the end of August but the Apiguard I applied didn't appear to be fully dispersed. We applied OA treatment in December resulting in a significant mite drop.

 

[robmort]

....... as I had expected and was prepared for, were small clusters of dead bees on comb, plenty of stores......

You say "plenty of stores" but your pictures don't show that unless they're somewhere else.

 

[Erichalfbee]

Strong colonies high mite numbers poor response to varroa treatment. Most of us can’t be bothered to check mite numbers after treatment to make sure the treatment worked.

Yes a lesson I learned a few seasons ago. All my colonies on omf get an accelerated drop a month after treatment end. The ones in solid floors get a sugar roll.

 

[ericbeaumont]

kept bees successfully on this site for seven years and had never lost overwintering colonies

think both queens failed to lay winter bees. No varroa

both queens had failed/perished before laying the spring bees

It might have comforted you to conclude that the queens failed, but the photos show that late last year the queen was laying a decent amount of brood and that a stronger varroa infestation did for them.

Is it advisable for me to send samples

Seven years is a fair whack but it does depend whether your skills developed in that time, especially in terms of observation and in drawing conclusions from the evidence. In other words, no, there is nothing in your photos that shows anything worthy of further investigation.