Jim wrote

> Apis cerana is able to tolerate Varroa JACOBSONI, while Apis
> mellifera is plagued with the much more destructive Varroa
> DESTRUCTOR. (They named it "destructor" for a good reason!)
> While both situations can be described as "bees and mites",
> the similarity ends there.

But A. cerana is also able to tolerate V. destructor and A. mellifera is in
the situation where V. jacobsoni will not reproduce on.  Nor will V.
destructor reproduce on A. cerana that is the natural host of V. jacobsoni
and V. jacobsoni will not reproduce on the A. cerana that is the natural
host of V. destructor.

Why will V. destructor reproduce, quite successfully, on A. mellifera
whereas V. jacobsoni will not?

Trevor Weatherhead
AUSTRALIA