In a message dated 08/10/01 05:04:32 GMT Daylight Time,
[log in to unmask] writes:

<< Have you compared them side by side with hives on regular bottom boards to
determine the difference in the same apiary the same year? Has anyone on this
list?
  >>

I haven't done anything scientific in the way of measurement.  I have about a
third of my hives on mesh floors open to the ground beneath the stand (apart
from when I occasionally slide a tray in for a 24 hour test).  They certainly
don't appear to hold the colonies back.  My heaviest honey crop this
(indifferent) year was from a hive on a mesh floor.  I was also using small
celled foundation in that hive so there is more than one variable.

Chris