We were out at the Ortona Burial Mounds near La Belle, Florida this afternoon and we kept coming across these ant colonies! They were in just plain, white sand and seemed quite large in size compared to most ants we see around here. I wish we had something we could have used for scale, granted we were equiped with a camera but not much else other than hands and we all agreed we were not using those! These seem to be the worker ants but there were a few ants with much larger heads almost soldiering about while the others did their work. We were not sure if they were a type of bull ant or a beefed up version of the typical fire ants we see down here. It would be wonderful if you could let us know what they are! We do also have a video of them moving about and if you would like to see it please let me know and I can email that as well!
Thanks for your interest and observations! Based on the photograph and some of the clues you provided, I'm guessing these are Pogonomyrmex badius, otherwise known as Florida harvester ants. This species is unique in being the only one of 22 harvester ant species in the U.S. that occurs east of the Mississippi River. As you noted, these ants are considerably larger than most other ant species we're used to seeing, and they also display strong worker polymorphism, with major workers having larger bodies and disproportionately larger heads than minors. P. badius colonies nest almost exclusively in dry, sandy conditions in relatively open woodlands or grassy fields, which would explain their preponderance in the sandy clearings around the Ortona Mounds complex.
Thanks again for your curiosity,
Alexandra Westrich & the AntAsk Team