Varroa & genetic variability

[EK.Bee]

As Varroa are incestuous wee beasts (effectively clones ?)I've been wondering how they manage to maintain their genetic viability & develop resistance to varroacides ? Is it a result of random freq mutations of their DNA or the DNA mutations are not that freq but they breed more therefore throwing up a resistant strain quicker? Can someone explain?

[mbc]

Incest isnt always the case when there are more than one foundress mite in a cell.

[EK.Bee]

Ah hadn't occurred to me, so there can be multiple strains of Varroa in the one hive with the first born son of one strain mating with the daughters of another

[Jon]

The problem from the bees point of view is more to do with the change in the viral landscape when mites arrive.
Deformed wing virus has at least 9 variants and without the presence of the mites the bees seem to cope with these.
When the mites arrive the variant of DWV which is most harmful to bees increases at the expense of the other variants.
This was all set out nicely in the Martin et al paper which looked at the arrival of varroa mires on some of the Hawaiian islands.

There are two main strains of varroa, colloquially known as K and J, Korean and Japanese.