Re: Shriveled wing seen in one bee
OK well to give you a better explanation, the bee at the entrance showing deformed wing virus (DWV) might have been the only one in the hive. More likely though, there will be more. As these bees don't live too long, just a few of them would be a concern. The other thing to look for is at the capped brood. If there are serious varroa numbers they will be killing some of the larva, which is known as parasitic mite syndrome ( PMS ). You have to be observant, but what you do is look at a capped comb of brood, shake most of the bees off if need be to get a good look. If mites are killing larvae you will see the odd cell with a dead browny blackish colored larva in it. You will also see the occasional capped cell, which instead of the normal dome shaped cap, the cap is partly removed as the bees are beginning to remove the dead larva. If there is a cap with a hole in it and the larva inside is white, all is normal the bees just haven't finished buiulding the cap. But if it's a different color it is not normal for the cell to be uncapped.
BTW there are other (but rare) diseases that kill brood, but the dead brood looks a bit different, to discover more you could start by googling the serious one, AFB. But these diseases are rare, and mites are common, so if there's an occasional dead larva among the brood, the first thing to suspect is mites.
When a hive has light numbers of varroa mites they normally go one mother mite to a worker cell (more in drone cells), and the bee survives. It is mainly when varroa numbers get dangerously high that they start going several mother mites to a worker cell, and this is when they start killing the brood, and the hive could quickly be in trouble.
There are other ways to test for mites, but I'll leave that for others to describe, for me, I just go by the symptoms.
"We don't need no education" (Pink Floyd) - Yes you do, you just used a double negative.