My Aphaenogaster rudis colony was recently moved into a THA Mini Hearth Type III. A day after the move, I noticed a worker INSIDE the water tower (it was half full). I assumed it had entered through a microscopic tear in the mesh. I covered the small hole with some plaster and assumed that was the end of it. Today, when checking on them, I noticed FOUR workers stuck inside. This means they must be getting in some other way, and they don't seem to be able to get out.
WHAT SHOULD I DO PLEASE HELP!!