Update No.10 - 12/05/2021
I wasn't expecting to update this so soon, but here we go anyways! A fair bit has happened in such a short amount of time with the barbs, having completely filled the main chamber of their nest within the past two weeks from all the minors that have been eclosing in the current batch of brood. It's mostly just future media and and major larvae and pupae at this point though surprisingly the brood pile has remained relatively consistent in size. The queen has also has laid two new batches of ~30 eggs in total, so I can't see their growth slowing down anytime soon. If they keep growing at this rate, I'm going to need to get a bigger nest for them in the coming weeks.
I've also been testing humidity preferences for the messors, and found that they like to compact into areas with the highest humidity (we are talking in excess of 90% here). The second chamber that gives entry to the main chamber is much smaller and hence retains humidity better, so its not uncommon to find the barbs stuck in a black mass with all their brood whenever the main chamber's water reservoir is empty. After talking to some more knowledgeable keepers, this is quite common in smaller messor colonies where they don't have the worker numbers to effectively hydro-regulate and keep the brood moist.
I also got some more turkestan roach nymphs. I have not yet offered nymphs to my messors (they have had adult roaches, but never showed much interest in them); they have elicited quite the reaction from the barbs, so these might be a favourite.
The novomessor have also been doing incredibly well, the queen has been laying constantly and the first workers new generation are due to eclose tomorrow, when this generation has passed there should be 43 workers. They too, are fond of turkestan roaches.