The difference is that varroa mites are much larger relative to a bee, and are on the bodies of both adults and larvae. And the beehive has lots of bees whose j

The difference is that varroa mites are much larger relative to a bee, and are on the bodies of both adults and larvae. And the beehive has lots of bees whose jobs are cleaning the hive and greeting the bees returning from flight. And the mites aren't known for excreting some magic pheromones like other, less harmful beehive parasites do. So there really is no excuse for bees to fall prey to these mites. I've read that some ants actively fight and remove parasitic flies trying to land on and infest them, so insects are definitely capable of this kind of self-protection. It's just specifically bees that do not have the genes, and cannot learn this behavior. Which proves their intelligence is severely limited.