Why do bees and sunflowers seem to go together?

Maybe it's the yellow colour scheme.

I guess they aren't always together.

Like salt and pepper, once in a long while you do actually see one without the other.

My "Anything Goes" strawbale garden has produced a satisfactory crop of sunflowers, with many more on the way as long as we don't get a frost anytime soon. I am not sure what this last one is--I think it was from the "mystery seeds" given to me by my friend Doug F. The closest I can find on the Internet is Little Becka. Have any of you seen this variety before?