Grooming behavior in bees was one of the mite-fighting qualities we were all excited to find years ago. It led to screened bottom boards where some 20% of the mites groomed off of a bee fell through the screen and onto the ground never to be seen again. That was a good thing. Along with SMR and VSH, it added something to the toolbox for natural mite fighting genetics from the bees themselves. That said, watch this video for what happens to the mites in that OTHER 80% of the time.
As you saw, the mite was groomed off the first bee. But then it just grabbed back onto that same bee again. When she groomed it off a second time, it jumped back on yet another worker bee which happened to walk over it. This wastes a lot of energy!
So the Heartland Honey Bee Breeders Cooperative partnered with Dr. Greg Hunt and Krispn Given at Purdue University to create a bee with genetics which included chewing the legs off of mites. Since varroa mites can’t coagulate. a chewed mite is a dead mite!