Wilson (in Brown 1960) made observations on a colony fragment of this species, captured at Pueblo Nuevo, Veracruz, Mexico. He noted that the colonies were polydomous. The fragment he obtained contained workers, eggs (which hatched in the laboratory), and a dealate queen, but the queen was unfertilized and apparently not the colony queen. When he offered the colony fragment a variety of prey types in a "cafeteria" experiment, the foragers mostly recoiled violently. When the ants were cramped together with a 15mm long geophilomorph centipede, they did attack and sting it, finally killing it and dragging it to the brood chamber, where some larvae began to feed upon it. But it was not clear whether this was a typical prey item.

I know this species from Hitoy Cerere at 200m, the north slopes of Volcan Barba from 500-900m, the Penas Blancas Valley from 800-1000m, the San Luis Valley west of Monteverde, Carara Biological Reserve at 500m, and Manuel Antonio National Park near sea level. These are all wet or moist forest sites. modesta inhabits the leaf litter and dead wood on the forest floor. I only know it from Winkler samples of sifted leaf litter, in which I occasionally obtain dealate queens along with workers. Zobeida Fuentes, a Parataxonomist working in the San Luis Valley, found scattered workers in a dead stump, in a patch of mature forest.