All I can do is add one year's unscientific observations. In May, I shook
two colonies onto the 'small cell' foundation available from Thornes
(actually about 5.1mm). They didn't like it, and one absconded; this could
have been due to the change in cell size, but could just as easily have been
due to starvation, as the weather was lousy, and another local beekeeper
reported losing a colony which absconded at about the same time, apparently
due to starvation. This colony was later replaced by a swarm, giving me two
partly regressed colonies. One of these was lost when the queen became a
drone layer in the autumn.

    Both colonies laid down ample winter stores; in previous years I've had
to feed in autumn. After downsizing, both showed quantities of bald brood. I
didn't dig around in the comb to see what was going on, but based on the
reports of others who've seen the same thing in small cell colonies, I
believe it to be a response to the presence of foreign organisms like mites
or wax moth larvae in the cells. Consistent with this, I found that a large
proportion of the mites falling out were transparent immatures, all bearing
bite marks. I've never seen this before.

    This is all very unquantified and unscientific, as I wasn't well over the
summer. All I can say is that some behavioural change appears to have
occurred, involving the appearance of bald brood, and that this appears to
correlate with the appearance of damaged immature varroa on the hive bottoms.
Hopefully I may have something clearer to offer next year.

Regards,

Robert Brenchley
Birmingham, UK