I was out walking just before dusk yesterday and I came across a thread-waisted wasp (family Sphecidae, possibly Ammophila pictipennis). It was in a curious posture. Its jaws were fixed firmly on the base of a common ragweed flower (Ambrosia artemisiifolia, Asteraceae). Its abdomen was held out at an odd angle, and it didn’t move except to twitch its antennae. At first I thought it was feeding, but ragweed is wind-pollinated and probably a poor source of nectar.
After reading a bit, I learned this wasp was getting ready to sleep. They latch on to plants, adopt this unusual pose, and remain immobile for the night. I don’t think it looks very comfortable. Apparently a busy day of feeding on flower nectar, provisioning nests with moth larvae, mating, and laying eggs can really wear you out.