Aaron Morris wrote:
 
> Stan Sandler wrote:
>
> >> If so, a drone method selects
> >> a new mite population with preferring lady bee brood ...
> >
> >What an interesting observation, Rimantas!  And logically correct.
>
> Actually, this is not logically correct - drone trapping should not
> select for mites that prefer worker brood, and here's why.  At the time
> when one employs the drone trapping method there is plenty of drone
> brood available to accommodate (play host to) all the varroa within a
> hive.  It is not until late in the season when there is not enough
> drone brood to go around that varroa migrate to worker brood.
> Presumably when drone trapping, the dynamics of the varroa population
> change.  You only select for varroa who prefer worker brood if you let
> the dynamics reach that point.  If you're drone trapping right through
> the season the mites never reach the point that they are forced to
> select their second choice (worker brood).  There is a great article in
> this month's ABJ written by Bob Horr dealing with this topic.  Highly
> recommended!
>
 
Hi All,
    The factor that has made the impact of varroa on western beekeeping so
great is that in western bees varroa mites do enter and reproduce in worker
cells as well as drone. The rate at which worker and drone cells are
infested are a constant for a given colony and is based on the number of
worker and drone cells being capped, and the population of the colony. The
ratio between these rates is a genetic based variable and may be an
important factor in selecting for varroa resistance.
    I'm not sure if anyone has figured out what causes this. Juvenile growth
hormone, qualities of nurse bees, larval food have been considered. Perhaps
a scientist out there can help with this. In any case, the effectiveness of
drone removal to control varroa is dependent on the specific bees being
treated as well as any preference for drone or worker larvae the mites may
have.
    Another point to consider is colony dynamics. The number of drone larvae
in a colony is among other things inversely related to the number of drones
in a colony. If drone brood is removed there will eventually be a "shortage"
of drones. The colony will respond by producing more drone cells. I think
this would help if you are trying to use this control method. The number of
drones is also related to colony strength. I wonder how the method works
when there are many weak colonies?
    So, getting back to the idea that varroa may become resistant to the
drone removal method, I personally think it is possible but not probable
because other, more common, control methods are in use. These other controls
will interfer with the resistance to drone removal devoloping.