2 of my colonies have vanished

[danno]

I was finishing up installing mouse guards yesterday.   It was a warm day and the the bee's were active.   They would come out in numbers at the sound of the staple gun at the front door.   I found 2 colonies in 2 different yards that had just vanished.  Both had small patches of brood.  One was abit light on stores and the 2nd was loaded to the hilt on stores.  The 2nd had 10 full frames in the top box and a crest of honey across the tops of all the bottom frames.   Neither had any robbing going on.  They had absolutely no bee's in them.   

[AllenF]

Aliens. 

[danno]

Its just strange Allen.   Its strange that not a single bee stayed or even died in the hive and even stranger that both of these yards are 5- 4 way pallets or 20 colonies each and there was no robbing going on.   The yards are about 15 miles apart.   One was new this spring and the other was new in spring of 2011.   They just obsconded.

[AllenF]

I had one of this years swarms disappear a few weeks ago.   I figured robbing killed them.  

[danno]

the only thing I can think of is they got tired of me bleaching there top bars. 
The frames of honey always come in hand for spring splits and swarms  

[10framer]

hive beetles?

[danno]

hive beetles?

"Knock on wood"  They are not a problem yet