Solitary bees and wasps have all sorts of really interesting behaviours, but one that I’ve only recently witnessed is what the bees in the photos below are doing. Towards dusk when they’re frantic daily activities are drawing to a close the males of many species seek out places to roost and the bees in the first two photos have chosen a suitably thin, dry plant stem. Lots of bees of the same species were doing exactly the same and clamping onto to the tips of plant stems with their mandibles. This seems like rather odd behaviour since the roosting spots are very exposed, however, they’re well out of the way of most predatory arthropods that are wandering about at night.
Similarly, the males bees in this third photo have chosen a dried flower-head at the top of a long thin stem, but the difference here is that these chaps roost communally with several individuals all clamouring for space. As the temperature drops and darkness descends the bees enter a state of motionless torpor until the morning sun heats them up again.