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:
Attachment 81
Dead bees in a cluster near the tops of the spaces:
Attachment 82
Cluster with perforated cappings away from the cluster:
Attachment 83
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)
Attachment 84
On one comb face, stores immediately adjacent to the cluster:
Attachment 85
... 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