Good heart

It's nice to open a colony and find that things are going right. We seem to have had more than our fair share of the opposite this year. This is what a frame of capped brood looks like in a strong colony. The queen has filled this frame with eggs in a relatively short period. The eggs have hatched more or less together and the larvae have grown for 4 or 5 days in open cells, then the nurse bees have worked their way over the frame in the course of just a few days, creating these lovely digestive biscuit-coloured caps over the top of each cell

The caps are all flat, indicating that every closed cell contains a worker larva, producing a lovely savanna-like effect accross the whole frame (excluding a small area they have reserved for honey). They will sit like this for 12 or 13 days, while the larvae inside pupate and metamorphose into adult bees. The nurse bees then chew off each cap, and a new worker emerges 

If you look very closely, about one-third of the way down from the top, you can see six cells from which the nurse bees have removed the caps, exposing the still-white face and eyes of the partly-developed bee inside. I'm not entirely sure what's happening there, but two possibilities occur to me. One is that the bees may have detected Varroa reproducing within these cells, and removed the caps so that they can eject the Varroa. This 'hygienic' behaviour is only observed in some colonies, and very much to be treasured, if that's what it is 

The other possibility is that these are in fact 'rogue' drone larvae. A young queen like this one may lay the occasional drone egg when it was not intended. Earlier in the year, the colony would have happily raised these to maturity, but their tolerance of drones disappears in August. Adult drones are ejected from the hive to die, and not permitted to re-enter. Drone larvae, are liable to be uncapped, pulled from their cells and disposed of outside the hive. You can see that there are a few other empty cells dotted around the frame. These may also be larvae that have been removed, or they may be cells that have been deliberately left empty so that, in the event of a cold snap, 'heater bees' can put themselves in these cells and vibrate their muscles to produce heat and keep the brood warm

Bees doing their thing