In the sun or out?
I chatted with a new mason beekeeper today who was confused about directions on a flyer, the web and various other sources. He had bought some mason bee cocoons from a store and the flyer instructed him not to set the package of cocoons out in the sun. Then further down, directions were to set the house with the nesting tunnels in the sun. How confusing!
When bees are still in their cocoons and cannot move about, do not set box of cocoons in direct sun. The heat of the sun could cook them while they are still in their cocoons. The best place for cocoons are within the shelter of a mason bee home under the roof- away from direct sun- but nice an warm.
The house for mason bees should go into a sunny spot. Bees like to be warm when working and young offspring need the heat to move, eat and develop into adults.