in my ant farm I have the ants in a tube on the surface of the loam. On one side of the farm I heaped some of those clay granuales to form a ramp to the drilling hole. The ants (ligniperda) work tirelessly toblock their tube up every day with the clay stones, then just seem to unblock it again later and repeat the process. The ramp is now completely gone and all the clay is just piling up outside the tube entrance. Fascinating behaviour, but makes me wonder why they don't just leave a small entrance instead of destroying it and rebuilding it over and over.
At the early stages of the colony, they will likly be nocternal, its likly they are blocking the nest up during the day to keep it safe, then unblocking at night so they can forage, or vice vesa