Well I guess I'm dragging this back from the dead.
I was out checking out the exsecta-group formica mounds today, and the ants are starting to wake up. Anyhow, I brought home a specimen (worker) for ID (pretty sure it's exsectoides), and didn't really know what to do with it once I'd finished my ID. I remembered hearing about this, and figured maybe I'd try introduce the exsectoides worker to one of my parasite colonies with this method.
Dunked the worker in name brand white vinegar for 15 seconds on the clock, placed it on a piece of tissue paper to dry off, and then offered it to my Formica subnitens colony, which has the one subnitens queen, 2 or 3 pacifica workers, and 1 fusca-group worker.
Needless to say, it was somewhat shocking to see probably the most aggressive ant in my area as docile as a lamb.
2 or 3 hours in and I've seen it share food with one of the pacifica workers. For all intents and purposes this ant appears to now be one of the family. (Actually as of writing this I just watched it share food with the subnitens queen - exciting stuff)
Now I will gladly discuss the ethics of waterboarding ants in acid, and I can totally see how people think making multi-genera colonies just for the heck of it is frivolous and ethically wrong.
But I would like to propose that this method offers a quick and easy way to introduce Formica hosts to Formica parasites, with no need for brood (which in the city is worth its weight in gold and only actually around for maybe a third of the year). Additionally, it offers a humane method for "disposing" of Formica ID specimens when you're done with them, as long as you have a Formica colony.
Now I totally get that this is all preliminary and that the worker is by no means home free just yet. I intend to keep an eye on things and see if the worker suffers any ill effects from the vinegar or if aggression develops within the colony.
But if not, as I said, this could be a valuable way to provide hosts to Formica parasites (and Lasius parasites too I guess, if you're into those ).