My observations of wild hives finds them in the shade and things I've read about placing swarm trap say that the bees will reject a trap that is not shaded.
I am thinking in the wild you don't find two many pretty boxes sittin out in an open field in the sunshine to build in
Just kidding. I think we have adapted beekeeping as we want it not as the bees want it. And along with that we have found some pest like the sunshine less. And also a hive that warms up quicker sends bees to foraging earlier. In the wild the bees could care less about the extra honey that they may make in the sun. They just want thier needs satisfied and they hoped to split themselves to help the cycle going.
So yes sunshine it is.