Having read a lot about symbiosis, I still found a bunch of novel interesting stuff here. e.g. how acacia makes ants dependent on them:

>These acacias are quite notorious for another reason: The nectar they provide contains an enzyme that makes it harder for the ants to digest the nectar of other plants. Yes, the nectar contains an enzyme, chitinase, that makes the ant’s invertase, a sucrose-cleaving enzyme, inefficient. This essentially forces the ant to feed on the acacia’s nectar, which is poor in sucrose, rather than foraging on other nectars.

Isolating each ant colony in its own compartment is the detail I hadn't seen before. Partitioning as a way to keep partners honest.