Yesterday afternoon I found some Carpenter Bees (Xylocopa virginica) apparently resting on phlox blossoms. They were crawling up under the flowers and then just clinging there without moving. Some were more concealed under the flowers than others, but they were all trying to rest along the base of the blossom, near where it joins the stem.
I have seen bees do this before, but usually late in the evening or early in the morning. I had figured they were going into (or coming out of) some sort of torpor for the night. In the middle of the day, though, it seems like they should have been at the peak of their activity. So I am not sure if these bees were just resting or if they were doing something else.
Most Carpenter Bees burrow into wood, sometimes including residential structures, for nesting. They are generally solitary, but sometimes cluster their nest burrows together. Each nest has a single circular entrance hole that branches into multiple chambers where the larvae develop.