I love encountering entirely new species! I had never heard of an acrobat ant before I got a photo of this little (3mm!) lady.
Acrobat ants get their name from their ability to raise their abdomen over their thorax and head when disturbed (you can kind of see this one lifting her butt at me threateningly). They are also called cocktail ants, for similar reasons. (Wikipedia tells me that, because of their heart-shaped abdomens, or gasters, they are also called the St. Valentine ant.)
Crematogaster ants are omnivorous, eating other insects (both live and dead), plants, seeds, and nectar. They use venom to incapacitate their prey, and hunt socially. When a group of ants captures an insect, they inject it with venom, grab its legs and pull it spreadeagled, and then haul it cooperatively back to the nest. Acrobat ants are arboreal, so the nest is often in a tree.
The two distinct spikes on its thorax are called epinotal spines, and these were the primary characteristic I used to identify this ant. There are several species in the genus Crematogaster, and they all have the two spikes to one degree or another. I’ll admit I may have lost my mind somewhere in the identification key, but since antwiki.org and bugguide.net seem to have differing opinions on what defines each species, and I’m just a goofball with a camera, I have to find my limits somewhere. I think this looks closest to Crematogaster cerasi, based on physiology and geographical location (central Florida).
Actually, the spikes aren’t on the ant’s thorax; they’re on its mesosoma, or possibly its propodeum. A brief foray into ant identification has introduced me to a terrifying new world of vocabulary and anatomy, which I prefer just to visit.