The entire room is heated and humidified by a 200W aquarium heater. Basically there is 50mm of polystyrene around the whole room. Then I built what is basically a huge fish tank so all the walls are glass. I then built shelves from glass also but each shelf has a raised front so they can be filled with water. At the end of each shelf is a hole so when I pump the water from the bottom shelf (where the heater is sitting) to the top this water falls from the top shelf to the next and so on. The action of this water working its way back to the bottom constantly means the room is very humid, there is little heat loss so the temperature is perfect and the flowing water ensures the ants cannot escape. I place each tub on an upturned 10cm plant pot and move the lid to the side to allow the ants to forage on the outside of the tub. This system works very well with large numbers of Leaf Cutters.
