> A biological explanation for these species-specific differences is difficult. The dense and hard cocoon cap structure could protect the A. cerana drone pupae against cannibalism behaviour of the nurse bees, probably as a consequence of the queen-worker conflict on the optimal sex ratio of the brood. But this does not explain why such a behaviour occurs in A. cerana alone. Another hypothesis is related to the V. jacobsoni-specific hygienic behaviour of the nurse bees. A. cerana worker bees are very effective in uncapping and removal of V. jacobsoni-infested worker brood. In contrast, mite infested sealed drone brood is removed to a very low extent. Also freeze-killed worker brood is removed quite fast compared to freeze-killed drone brood. It is not clear if A. cerana bees avoid removing diseased or mite-infested drone brood, or if they simply are hindered by the hard cocoon cap. 

The pore in the hard conical Apis cerana drone capping results from a spinning process.
Otto Boecking. Apidologie Volume 30, Number 6, 1999

My reading of this is that the cap of the cerana drone is hard to remove, and the hole is probably for air flow. When it is closed, the drone dies. Apis mellifera uses a porous capping on the brood which allows the brood to breathe. According to this work, cerana honey bees are far more likely to remove mites from worker cells than drones. They seem to let the drones go, on account of the hard cap, or maybe they just don't care about them.

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