Howdy.

I've been reading up on all the posts to bee-l and following the
threads on varroa and breeding. We're working with several bee
breeders using insemination and selection and observing varroa/bee
interactions.

Harbo's work to breed a heritable trait (SMR) along with Spivak,
Rinder et .al with the Russians and the collective breeders of the
HIP project working with hygienic behavior and general survivability
brings us all lots closer to the time where we might be able to
keep bees more easily with varroa mites in the colonies, on the
bees.

However, one serious aspect of breeding for tolerant bees that
needs to be addressed along with varroa tolerance is the bee's
ability to fend off the virus(es) that varroa mites (and maybe even
tracheal) vector to the bees or activate within colonies. In the
literature ( email me for a bibliography ) studies show that even
after mite populations are lowered within colonies, virus levels
may continue to rise, until the colony collapses. SMR and hygienic
behavior is a great start, but selection must continue (and it
does) with the colonies that have not only low mite loads, but then
overwinter well.

The HIP project uses a term for this called "untreated thriving
survivor".  UTS colonies make it through two years of varroa
infestation. HIP breeders are not concerning themselves with the
mechanism of the UTS colonies survival at this point, but just
selecting for it.

I think of breeding for varroa tolerance as a two phased approach:
selection for low mite levels in infested colonies and selection
from these colonies for survival in the subsequent years after
queen introduction. Other breeders are trialing all the lines in
the bee press:  SMR, Russian, HIP, Minn. Hygienic and looking for
pure and mixed combinations that provide healthy, productive bees
that overwinter well and continue to produce into the next season.

All this takes time, but progress is being made. With any bee stock
you purchase from anywhere, the health and condition of the queen
bears the most on the colony's performance. You might purchase a
beautiful queen from an exotic pedigree of resistant stock, but if
she's not been produced well or she sits in the mail for too many
days, she's not going to do well for you.

Chow for now.
Sincerely,
Adam
--
Adam Finkelstein
[log in to unmask]
http://www.ibiblio.org/bees/adamf