Adobe dwelling

Removing a hive roof recently I was surprised to find what looked like a bright yellow sweet wedged into one corner. I knocked it with the hive tool and it fell away revealing what looked like a tiny igloo made of clay.

Who lives in a house like this?

The bright yellow substance fell apart when touched. It was actually pollen that'd been packed into the corner and walled up with mud. I think it was the work of some sort of mason bee. There was no egg or grub in the little house so maybe the bee hadn't got round to it yet or perhaps the spider I also found in the roof space had already taken it.