If it had been bees I'd have said trophallaxis but didn't think worker wasps exhibited such behaviour. Maybe I need to get out more?Difficult to tell scale from the pics, but they look like two workers.
The queen is much bigger (as you probably know, from seeing them appear in the spring after hibernation, looking for possible nest sites).
The drones are somewhere between the queen and the worker, noticeably larger than a worker, but smaller than the queen.
Don't know if that helps with regards to the pics!
Just sniffing each other out?
If it had been bees I'd have said trophallaxis but didn't think worker wasps exhibited such behaviour. Maybe I need to get out more?
Would either bee or wasp practice trophallaxis out in the open air like the video?Wasps do practise trophallaxis, same as bees.
As larvae, the regurgitation of sweet substances keeps the adult coming back to feed them protein. Adult wasps also share sweet resources, e.g a baited wasp trap.
As an aside, if a wasp gets into the hive unhindered and takes on the hive odour, it can go in and feed its compatriots through the omf. (Same goes for robber bees.)