Photo by Bob Thomas, Refugio Amazonas Lodge, Tambopata National Park, Peru, November 2007.
Also called the hormiga bala, giant tropical ant, and 24-hour ant (the latter due to the 24 hours of sickness and pain that follows a sting), this ponerine ant is one of the most feared animals of the Neotropics. It is said to have the most painful sting of any insect. They tend to nest at the base of trees, and they swarm anyone who mistakenly places a foot in their lair. Many a naturalist has been bushwacked by bullet ants.
These ants are mostly carnivorous, taking live insects and possibly scavenging. They have been observed using extrafloral nectaries, carrying drops of nectar in their mandibles back to the nest. They typically forage alone, and range from the ground to the canopy.
They may be active during the day, but are primarily nocturnal. The top photo was taken on a 100 ft tower in the afternoon, and the lower photo was taken in a rain pool while chorusing frogs were being observed.
Janzen, D. H. and C. R. Carroll. 1983. Paraponera clavata (Bala, Giant Ropical Ant). In: Daniel H. Janzen [ed.], Costa Rican Natural History. Univ. Chicago Press, pp. 752-753.
Morgan, Randy C. Giant tropical bullet ant, Paraponera clavata, natural history and captive management. http://www.sasionline.org/default.asp?go=antsfiles/pages/bullet/bulletbio.html.