Ah, good link Chris. Yes, I meant leaf-cutter ants but typed carpenter ants. One of the hazards of posting with too little sleep. I had been unaware of the complexity of the process involving specialized ant-poo enzymes though. There's no reason that evolution would select for simplicity per se, and moreover if it were simple to digest cellulose and produce net energy you'd expect a lot more organisms to have the ability as a fallback metabolic adjunct. Anything we find going on in ant and termite guts is likely to be complex or we'd see that it had evolved multiple times in different species. (Idle ponder - why is this only significantly seen in social insects - foraging efficiency and marginal EROEI?)

That seems like a good question. How far can we get with the idea that what in social insects is called cultivation, is called parasitism in the loners? Some wasps are evolved to lay eggs in caterpillers. If they were more social they might raise the caterpillers? Perhaps it is just a matter of needing to devote constant attention so the social structure is required?

Chris