I read that apparently, queen-bees allowed to do their own thing will do that thing with around 20 and possibly many more drones. As the queen tends to fly significantly further from home ground than her own drones, she mates with "strangers". In selecting a likely egg to raise as a queen, the workers will choose the ones with the rarest patriline; I'm not sure if that means they choose the ones of which the fewest of their sisters share a father or simply the rarest...maybe the most completely different genetic makeup from the rest of the colony. So bees have inherited behaviour patterns which actively seek maximum variation and minimum inbreeding.
The above behaviours seem incompatible with the concept that we should try to seek, as the title puts it, "racial purity in bees".
As for Icelandic horses, I presume they are a breed and not a sub-species. I know even less about dogs than I do about Icelandic horses and bees, but I am aware that a lot of "pure" breeds of dogs have an inherent propensity to specific health issues which are related to their genetics.