At dusk, around 18:20, this wasp appeared on the newly created sand area with parsnip plants, a male European beewulf (Philanthus triangulum) . He landed on the grip of a small shovel and enjoyed the view for a short moment.
Then he flew up, landed on the sand and quickly disappeared under ground with a few fast digging movements. First he moved some sand with it’s front legs and transported it away underneath his body creating a small hole in which he crawled. Then by moving more send the hole was closed behind him and once it was closed there was no more movement. The cover hole was barely visible from the surroundings.
Looking at the time and the fact that there was no further movement in the sand I suspect that he was looking for a place to rest for the evening.
The next day two males appeared around 16:30 and they inspected the sandplain for a long time by landing on different spots and dig in the sandy surface.
Here speciment 1.
And specimen 2.
One of the wasps also inspected the resting spot of the wasp from the day before, but after moving some sand it moved on. These males as well disappeared underneath the sand.
Somewhat later a female appeared that immediately started heavy digging.
She dug out a lot of sand and appeared to construct another opening from the inside out, next to the main entrance. She disappeared repeatedly into the hole and would come out with a heap of sand between the front legs, which she deposited in front of the entrance. Than she would move a little further in front of the heap and start shooting the sand underneath her body with her front legs. When moving the front legs back to the starting position for the next shove she would move a little towards the entrance. This would repeat until she was content and had moved the sand some centimetres further away, creating a fan shape.
At a certain moment she stopped digging and did not emerge outside the burrow any longer. Also the sand was quiet.
I’m gonna check out the coming days whether she laid the base for a nest, which would be great.
References1 Nederlands Soortenregister