Further to the discussion. Even if a species is resistant due to grooming and so on, it is unlikely ever to be totally free of a parasite like varroa. Apis Cerana the original host species co-exists with Varroa it does _not_ eradicate it. The problem with Apis Mellifera it that it doesn't even recognise Varroa as a threat, so it doesn't (unless the rumour is true) even try to groom it out. If one treats Apis Cerana with Apistan one will get Varroa knockdown, even though Apis Cerana is resistant! Buckfast bees _are_ pretty resistant to tracheal mites as are most UK origin bees (although Buckfasts are now bred in the Canary Islands). Incidently, I use some New Zealand/U.K. cross bees and find them very nice to keep, prolific and good workers if a little hungry in the winter. I haven't used American bees (yet?) because of recent import restrictions into the UK due to Varroa. The NZs I've used have been susceptible to tracheal mite which is somthing of a down side. Regards, Gordon.