I don't know if they eat ants, but they certainly go for the larvae. I found some the start of an ants nest last week in a pile of cut grass that I was using to line a potato trench (I really should have planted me spuds weeks ago but I'm still at it, as I clear the ground). They love it.
I have worked out how to keep Ramoth in. The door has a second catch at the bottom - I saw her poking her head out of a gap. And the moveable extension is double netted so there won't be any gaps and broken threads.
Now how can I teach them to do what the Soil Association says they will? They have a huge wood-chipped area that they have already stripped but they still scratch the grass as well as eating it.