A little over a week ago I was poking around in the bee hives. The weak hive had two "supercedure" cells on it.
There are two types of queen cells, swarm cells and supercedure cells. The egg that goes into queen cells is like any worker bee egg, but it is fed differently and has a larger space to grow in. The space and diet is what makes it a queen instead of a worker.
Swarm cells hang on the bottom of the frames and are created when the hive becomes overcrowded. Eggs are laid in the swarm cells and new queens hatch out of them. They swarm away with part of the bee colony and that relieves the stress due to overcrowding.
Supercedure cells are built hanging off the comb, as in the photograph. They are built by expanding normal worker cells.
I don't know why my bees have found their old queen unsuitable. I do know this hive has been dramatically weaker than the other hive since I first installed my bees. Even after "stealing" a couple of small frames of honey and brood from the strong hive and placing it in the weak hive, the weak hive is still way behind.
Maybe the old queen is aging and not as productive as she should be. Maybe she is physically inferior in some way. Whatever the reason, the new queens have probably hatched by now. The first one to hatch will kill the second one, and then it will kill the old queen.
I'm looking forward to seeing how the hive is doing. I'll probably take a good look this weekend.
I don't know if worker bees will build swarm cells when a hive is not already crowded; I think they are programmed not to. Even if they did, I don't know if the current queen would lay in those cells. She is probably programmed to not lay eggs in queen cells if the hive is not crowded. I'm just guessing, but I suspect that is why supercedure cells are built the way they are. The unsuspecting current queen lays normal worker eggs and then a couple of them are made into queens on the sly. Nature sure is tricksy sometimes.