Had our camper set up for a week unsupervised recently after some heavy rain. When I got back to pack it up I noticed a few ants around the trailer so decided I'd clean it out when it got home. Just as well because in that week thousands of the little sods had set up home between the spare canvas in the tub.
If they get in, clean em out quick. It never occurred to me to keep an eye on them while the triller is in the yard.