ant fights

Here's a question for my myrmecologist readers.  Has anyone published observations of ritualized fighting among colonies of Pogonomyrmex harvester ants?  I know such behavior was famously studied by Bert Hoelldobler in Myrmecocystus, and that ritual combat has been noted in Camponotus and Iridomyrmex.  The reason I ask is that the pogos in my front yard back in Tucson would engage in what looks like the same sort of behavior.  Ants from opposing colonies stand up on little stilt-legs and push each other about without anyone getting hurt. I suspect these non-lethal ways of establishing…