Well, this was the last dance - The next morning I transported the girls to their new foster home. This will be temporary. We are looking for their new home still.
This is the first time I saw my honey bees dance all in unison. This is what they call wash-boarding, and experts are still not sure why they do this, and where the music comes from.
It's been observed that the bees that participate in this activity are mostly workers between the age of 15 and 25 days. Mostly at the end of a nectar flow. It's unknown if this is general cleaning activities. Studies show that this happens more often on coarse textured surfaces than smooth. My observation is that it happens more in the (hot) evenings.