We have Argentine ants (according to that page) and they are giving us a hard time. I can't figure out where they come from and where they are going to. We have a wooden ceiling and then the metallic roof (penthouse-like) and I think they like the wood or that they live there.
They are often found on the kitchen top, especially if there are crumbles or cat food (even 30 or 40 at time). I found them also on the kitchen stove, they were walking to the back of the appliances. I also found them in the kitchen secondary sink (the kind they have here in Argentina, an utility sink). I found some (3-4) in the kitchen cabinet where we store dry cat food (sealed in plastic bags like those they use here for vegetables, might have tiny holes).
One day I had dirty dishes that had been sitting there waiting to fill up the dishwasher and there were maybe 60 ants in the dishwasher (which was of course closed, but apparently the bastards can find their way in anyway).
We also found ants walking on the wall of our bedroom, up to the ceiling (we have carpet in the bedroom, which was professionally washed twice in 7 months, so it is CLEAN).
Today I found an ant wandering in the bathtub (in the bathroom with the wooden ceiling).
We have a professional exterminator coming to our building once a month, and we spray our share of raid whenever possible (i.e. not near cat food or in the kitchen, but on the external walls, on the balcony, on the creeks in the ceiling, etc.)
They are tedious to say the least!