Tim,
I live in central Florida about (15) miles north of Orlando. I have
installed wire mesh bottoms all of my hives. I have installed them on top of
the bottom board. I have not noticed a reduction in bees staying outside
during the hot weather.
I find the major advantage of the mesh screen bottoms to be IPM. SHB, larva
(wax and shb) will fall through the screen onto the plastic coated cardboard
that I slide in from the back. Periodically, I add a sticky board to monitor
for mites, shb, wax moth and other pests.
Richard