probably depends on the species. The ones I have I have never found outside of the tubs. I should post some pics of them sometime.Just be careful though, the adults will bite if they get out. Also, they can and will eat old books too (or really anything organic) if they get out. We kept a couple large colonies of these in grad school as a way to skeletonize fish. More than once we discovered an escapee after it had bitten our foot!