>   The cell was empty. What would cause
>this?
>Thomas J. Martin


I see this fairly often. Bees building, and then tearing down queen cells.
Building more, and then tearing them down, too.

With only one cell started, it could be that the bees just didn't want a
cell started. With cells constantly being started and torn down...I'm not
sure, but I have the feeling that it may be a caste thing. Different castes
behave differently than others. The queen lays in cups, and one caste cares
for them, and as they mature, other castes tear them down...to maintain
status quo???

Just a guess

Mike