I'm a little concerned about this Formica subsericea. They have a dark nest under the sand, but during the day the queen comes to the surface. If she hears a noise they all run underground as shown in this video.
They seem unsettled. I'm going to offer them a test tube in their outworld to see if that helps?
I don't know why they don't stay underground. It's not over moist or dry. They also spend very little time in the outworld. It's amazing how fast they move.
Until about two weeks ago they had lots of eggs and brood and were in a small nest box. But the brood tampered off so I tried moving them to this new set up a week ago. They dug a nest but have not really taken to it as this video shows.
Hm.