This is a collection of all the sleeping wasps and bees I have encountered during night macro. You won't find them sleeping like this during daylight.
Sleeping blue cuckoo bee, Thyreus sp.
I don't like to sleep alone :D (Halictidae: Nomiinae)
Blue banded bee
Hover wasp (Vespidae: Stenogastrinae)
Another sleeping bee (Halictidae: Nomiinae)
Mud-dauber wasp (Sceliphrinae; Chalybion sp.)
Larrinae under the family Crabronidae. This could be a Liris sp. or another genus such as Tachytes; the specimen will be needed for identification.(IDed by: Vespa bicolor)
The same sleeping wasp
Sleeping bee (Genus: Amegilla; sub-genus: Glossamegilla - info credit: Zestin Soh and Doug Yanega). Selangor, Malaysia.
As you can see, some of them sleep by locking their mandibles onto the perches/plants while the others just rest on the perches. All taken with a 40D, MP-E65, MT-24EX and DIY concave diffuser, full flash.
Other wasps and bees
A male crown wasp (Stephanidae).