Chris,
You must have different Varroa mites in UK than they are in the U.S.
Female Varroa mites lay eggs with bee larvae, and the bee larva serves as the
food supply for the mites. When the bee emerges from its cell, adult mites
are "hooked on" to this new bee and feeding from the lymph of the bee. Adult
Varroa mites spend all of their time living ON THE ADULT BEE and traveling
where it goes INCLUDING swarms.
Irish beekeepers better learn more about Varroa mites, or you won't have many
bees shortly.
George Imirie