The AntsCanada Ant Forum's

Do you have to heat your outworld or is it enough to just heat the nest? And from where can I get a good heating cable/lamp and the thing that you use to control the temperature.

Pet store or amazon you are looking for a "heating cable" probably. Not necessary to heat as long as the room where the set up is, is not air conditioned.

I just have a regular desk lamp over the top on mine. I keep a heating cable in my hybrid nest when the colony is not hibernating, but the outworld I just let get heat from the lamp.

Be careful with heating the outworld though, some species (Crematogaster in particular, probably Camponotus as well) could see this as an invitation to pile all their pupae within the outworld.

Personally, i have my heat cables run along one side of my outworlds to create a temperature gradient for them. Of course i abandon this method when its warmer in my house during peak summer.