Dear All

What do my fellow Bee-Listers make of the recent research on the prospects
for Varroa-tolerant bees?  Not the Russian bees, it is pretty clear that
those who tried them had some problems as they inter-bred with local types.
More interesting, as far as I am concerned, is bringing out potential Varroa
resistance in the bees we already look after.  The honey bee breeding folk
at Baton Rouge have published a string of papers on the traits found in
all-American colonies with a degree of Varroa tolerance.  The implications
of this fine work are great: Varroa resistance is out there, and those who
are expert enough to practise bee breeding just have to identify it and
apply selection to the tolerance traits already in our bees.  There seems to
be no reason why we cannot have high levels of resistance in our own strains
of bees if we really want it.  If I can summarise the findings in their
April 1999 paper (Harbo and Harris 1999.  Heritability in honey bees of
characteristics associated with resistance to Varroa jacobsoni.  Journal of
Economic Entomology 92, 261-265):

·  they used 28 colonies set up so that each one in a group of 4 was headed
by full sisters from 7 unrelated queens.
·  the analysis permitted them to determine how heritable were a range of
traits which could give the Varroa tolerance seen in the mother queens.
·  heritable traits were 'suppression of mite reproduction' (partly due to
defective male mites produced on those bees), 'duration of capped period'
(not enough time to give full mite multiplication), 'hygienic behaviour'
(tossing out infected brood), and 'proportion of mites in brood cells' (if
they're not there, they won't breed).
·  the levels of heritability implied that good progress would be made if
selection was applied.

Several of these traits are readily scored, and I know that some enthusiasts
in the UK are already selecting hygienic bees.  The question now is: has
anyone tried putting these recommendations for Varroa resistance into
practise?  Perhaps those that have practised selection for any trait would
like to comment - how feasible is it to combine several traits in one colony
by selection?

Gavin.