Ants will also live inside treated lumber. I thought the treatment made it poisonous to insects. Ha ha ha, no. If the lumber is sufficiently old and semi-disintegrated, it might as well be sporting an Ants Welcome, Open House sign. If you then proceed to move the piece of lumber slightly (e.g. by dragging the lawn mower over it so the mower can reach the lawn), then all the ants will show up and swarm over the piece of lumber.

I'll bet ants hate earthquakes so much.