Hi Allen & all

Not wishing to put myself forward as an "expert" on 4.9 mm cells, but a
bystander that is more interested than most...

> My understanding is that it is forcing bees into cells that are
> a little tight that does the job, since there is less room for the varroa
to
> work,

My understanding is a little different here, my current thinking is that a
"european" bee raised in 4.9 is a fitter and more healthy individual than
one raised in any larger size. It is this robust health that allows such
bees to combat varroa. I say current thinking as I have yet to see a large
number of results from wide ranging and different climatic conditions that
would substantiate this.

> Apparently the bees do remove the cocoons
> from cells and the wall thickness does not increase significantly

I have not seen any evidence of individual cocoons being removed but I have
seen some good examples of the sidewalls (including the cocoons) being
chewed right down and then the walls rebuilt on the stubs
http://website.lineone.net/~dave.cushman/smalboldcomb.html
shows a good example.

> I notice that the coping is
> heavier, but does anyone have a study about actual wall thickness
measurements
> and dissection?

There is a partial page on my website, that I really must put some effort
into completing...
http://website.lineone.net/~dave.cushman/chriscomb.html
shows the shape of a plaster plug from a comb that was generated by Chris
Slade's bees. This plug shows quite a remarkable neck reduction (which is
typical of all plugs so far measured).

When this dissection work is complete it will throw up some averaged wall
thickness measurements at thre different depths within the cell.

Regards From:- Dave Cushman, G8MZY
Beekeeping and Bee Breeding, http://website.lineone.net/~dave.cushman
IBList Archives, http://website.lineone.net/~d.cushman