George,

Of course I agree that swarms will carry varroa mites, but during the
swarming season a mite will spend maybe 2-3 days on adult bees but 16 days in
a capped drone cell.  From this it follows that at that time of year about 4
out of 5 mites in a colony will be on larvae, not on adults.  If a swarm
leaves with say, half the adult bees they will take with them about half of
the mites NOT in the cells, ie, only about 10% of the total mites in the
colony.

If a swarm is hived and starts to rear brood it is very likely that the mites
will enter the first cells just before they are capped, say a week later.  If
this first frame of capped brood is removed a great proportion of that 10%
will also be removed.

These are rough and ready figures only but indicate that taking shook/
Taranov swarms may be a way of reducing mite levels for a while without using
chemicals.  It is far from being a complete answer to the mite but may be one
more tool in the box.

Regards,

Chris