File:Eciton burchellii, Neivamyrmex gibbatus, Costa Rica, Daniel Kronauer.jpg

Summary
Army ants are highly mobile and colonies sometimes cross paths. These encounters rarely escalate beyond the occasional scuffle. Instead, workers form a guard at trail intersections, facing each other one-to-one with their mandibles wide open, a sign of utter alertness. Eciton burchellii (left) vs. Neivamyrmex gibbatus. La Selva Biological Station, Costa Rica.

Photo by Daniel Kronauer.