Don, that is known as washboarding. It is what the foragers do when they are bored. Too hot for them inside the hive and nothing to collect in the field. At least, that is my understanding of the behavior. Just think of it as the bee version of line dancing!
Thankfully, the bees are smarter than I am. They are doing well, in spite of my efforts to help them.
The time spent watching them washboarding leads me to believe they are cleaning the surface of the hive and applying pheromones to the surface. The bees scrape the surface with the mandibles and stroke it with the antenna as they move back and forth.
42 + years - 24 colonies - IPM disciple - Naturally Skeptic
I was thinking it was guard bees in training sharpening up their stinger.
It's really cool to see that behavior! I haven't seen my colonies doing that yet.
Is this what washboarding means?
In this video these guys are saying that its a predator defense behavior! But I've never seen anyone else say it like this before! This could be what washboarding is! (I'm bringing it up for feedback, not as a claim. So I'm curious what others thing on this. Very possible over the years the behavior changed a bit as they got more domesticated.)
(To be fair though, the asian bees and large bees in Asia are apis cerana not apis mellifera. However they can still and do produce honey, but just are slightly different. And I am aware there are slight differences, but I don't think those differences are so pronounced. And it just so happens when people are describing washboarding doesn't it usually happen around landing areas and entrances mostly? Plus, people usually describe it in the evening, could be attributed to moths, and some types of flying predator insects sometimes can be more active towards the evening or cool periods?)
And someone did say their bees did the washboarding after a 'predator' was near the hive. So I think its a good possibility.