There's 2 main reasons you want substrate:
- Without a substrate stuff will just lie around and ooze all over the place. This isn't that much of a problem while the colony is small (and doesn't drag food around or poop a lot), it will become one with a large colony.
- Substrate not only soaks up fluids from food and ant poop, it also takes up ant pheromones making it easier for ants to navigate and communicate. Also many ants use visual guidance like landmarks and optical flow to navigate and you can mount those in the substrate (to prevent decorations like artificial plants from falling over).
Actually, there's a third one. Blank tubs just look ugly.
Edited by Serafine, September 14 2022 - 7:14 AM.