> I have observed many queens piping.  They stand still on the comb face,
> flatten their thorax and abdomen against the comb, extend their head and
> mouth parts forward, and appear to pump their abdomen to make the noise
> (actually much like a cow or lion bellowing).  When finished they stand up
> again and move on.  They may stop several times exhibiting the same
> behavior.
 
That's amazing! This afternoon during my inspection of their hive and
as I was finishing up I noticed the bees making a steady buzz all at
the same time in a harmonic tone. How do they make this sound?
Surely they don't rub their back legs on their backs like crickets do
to make this buzz? Piping? "You learn something every day."