Hi Everyone,
Some interesting comments on the effects of cell size on varroa
resistance in honeybees.  How important is cell size to varroa
resistance?  Some examples and references have been discussed but there
is another ongoing study that may give more information.  Tibor Szabo
and Daniel Szabo report on their ongoing breeding effort in Ontario
Canada in the June 2002 issue of the Amreican Bee Journal.  For five
years they have been raising queens from the colonies in their test that
have low varroa numbers, show hygenic behavior, and are good honey
producers as well as overwinter.  Their data show that the first three
years didn't seem to make much difference on varroa numbers but the last
two years have resulted in low stable varroa mite numbers.  They treat
their colonies with apistan but breed from those with the lowest varroa
mite populations in the fall.  It appears they are moving toward a much
more varroa tolerant/resistant bee population with thier selection
program.
Their results are not due to cell size as they have not resized their
combs but varroa tolerance is increasing due to the selection of breeder
colonies with lower varroa mite population buildup during the year.
Their results are very much along the lines of the results reported by
Erickson et all in their work in Arizona USA.  Selection for slower
varroa population buildup seems to work independent of cell size.  Of
course the SMR and Russian stocks show the same thing.  One can get
varroa tolerance/resistance by selecting for it regardless of cell size.

Interesting discussion guess we all should be selecting for reduced
varroa reproduction in our bees if we are raising queens.

FWIW

blane


******************************************
Blane White
MN Dept of Agriculture
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