Thanks for taking the time to answer my question. I was recently traveling in Costa Rica and happened to take a camera shot of some interesting ant behavior. I have no idea what is going on here, but would sure like to find out. Have you ever seen this kind of behavior before? (see attached image)
Please let me know.
Great image! What you have documented here, quite beautifully, is a number of Azteca workers "spread-eagling" a Pachycondyla gyne (future queen). This is an interesting and well-known behavior of the genus Azteca (Dejean et al., 2009), which is well known for its mutualistic associations with plant species (Cordia, Cecropia). The mutualism between the plants and the ants relies on the plants providing food and shelter to the ants, and the ants fervently defending the plants from herbivores and other competitive plants. This behavior, known as "spread-eagling", is usually employed by the workers to protect the plants from insect herbivores or intruders, and is not restricted to the plant alone.
Because the Pachycondyla gyne has not started her colony yet and become a queen (you can tell because she has not dropped her wings yet), it is likely that the Azteca ants are showing this aggression to defend their territory before she can start a colony and get a foothold in their area. Although the pictures don't show it, I'm guessing the gyne did not escape alive.
Hope this answers your question, I've included the reference below.
Max Winston & the AskAntTeam
Dejean, A., Grangier, J., Leroy, C., & Orivel, J. (2009) Predation and aggressiveness in host plant protection: a generalization using ants from the genus Azteca. Naturwissenschaften. 96:57-63.