Finman,
I've read you can encourage this grooming instinct in all bees by covering them in icing suger -
I just put this because small cell is not a key, neither sugar. I have no bees which identyfy it's prasite mite. Not help to my hives. I have Italians.
I have not noticed that powered sugar is recommended for serious method, neither screen bottom.
Beekeepers have awfully much good advises but only some works.