Over the past few weeks I’ve been bitten by ants in the genus Azteca several times. Once when we cut down the Cecropia, a couple of times when I was absently mindless chasing ants on a tree, and in Bocas after standing on ground nesting colony. While their sting is only mildly painful their power lies in their aggressive swarming behavior. Azteca is facultatively symbiotic with plants (like with Cecropia) where they defend it against herbivores in exchange for housing and food. However they can also create nests on/in other trees and (although I don’t see it recorded in the literature anywhere) in the ground. I expect that this high plasticity in nesting behavior would affect a number of other important individual and colony-level traits.
Many ants are aggressive when it comes to defending their nests although not al of them will be so aggressive to large vertebrate intruders. When living in Cecropia the ants will not only defend the stem, where they colony is located, but also the leaves from herbivores. While there are clear benefits to the colony I would guess that this comes at a high cost of worker mortality. If nesting in other places will worker aggression be lower?. The high levels of aggression needed to properly defend the host plant may be needlessly reckless if nesting in another location. Using a transcriptomics approach we could find differentially expressed genes among the locations. While there are genes that are linked to aggression, they may not be the only ones involved with such a response. The colony can also exhibit this aggressive response if individuals are more finely tuned to alarm pheromones, vibrations, CO2 or any number of stimuli.
I expect that colony structure will be highly affected by the location of the nest for because of the differences in availability of food. Cecropia nesting colony have continual access to protein rich food provided by the plant while this may be more varied for colonies nesting in other places. By measuring colony size, size distribution of workers in the field we could see these effects. Then a common garden experiment we could see if any of these traits are heritable.