Yes, that’s true. I think the best indicator of the situation is that I have in past years watered the area–not a lot, no more than once per month starting in late June or early July–and the bees still come back to that spot to nest every spring. I still worry about it though. I got a book on bees and read about the nest building of that genus, but didn’t really conclude anything either way, except that Diadasia is probably finishing up their nest building by July. The introduction of that book does say in general if you have ground nesting bees in an undesired spot, “repeated application of water may persuade them to leave.” Which doesn’t sound good but then again I only water them infrequently.