You can see the grooming several times a day in my video recordings. Sometimes “Grooming Bees” appear and work off one bee after the other. However, grooming is usually started without planning. Shaking and cleaning movements of a bee (that wants to free itself from pollen/parasites) are apparently the trigger. Under Videos I have already published both versions.
You can see individual grooming actions at any time of the day. However, there are also times in the day when there is a clear accumulation of this grooming behavior.
In the following video (46min) more than 20 different grooming actions take place, some of them at the same time:
Also in the next video (45min) social grooming takes place nearly all the time: