Gnamptogenys banksi (Wheeler 1930)

Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

John T. Longino, The Evergreen State College, Olympia WA 98505 USA.

16 September 1996

worker face view
worker lateral view

The large size and massive head make this species immediately recognizable in Costa Rica. The only other Costa Rican species of similar size is G. concinna. G. concinna is straw-colored; G. banksi is dark brown.


Ecuador, Panama, Costa Rica. In Costa Rica known from Hitoy Cerere, the Penas Blancas Valley (Eladio's at 800m), and the La Selva Biological Station.

Natural History

Lattke (1995) reported that this species was found in rotten logs in lowland rainforest, and that it was a specialist millipede predator. He reported known specimens from Barro Colorado Island (type locality) and Ecuador (Guayas, 3km S Bucay). I have now collected three specimens from Costa Rica: 1) an alate queen collected as a stray in Hitoy Cerere in 1985, 2) a nocturnal worker in Penas Blancas in 1988, and 3) a worker in La Selva in 1996.

The La Selva collection was remarkable. As part of the ALAS project, a large-scale arthropod survey project at La Selva, I have been intensively surveying the ant fauna over the last four years, and others have often collected ants at La Selva. The ALAS lab, which is in the laboratory clearing about 5m from the forest edge, has a screened-in porch. On 12 September 1996, at 3:00 in the afternoon, I was sitting in the porch on a coffee break. I saw a large worker ant moving rather clumsily across the floor, particles of lint sticking to its legs, with the appearance of an insect that had wandered into the porch area and gotten trapped inside. It was a worker of G. banksi, the third known specimen from Costa Rica and a new record for La Selva! This is a large, conspicuous ant. How could we have missed it?

How to collect

Possibly the best method is to search at night, looking for the large workers. You could also try taking more coffee breaks.

Literature Cited

Lattke, J. E. 1995. Revision of the ant genus Gnamptogenys in the New World (Hymenoptera: Formicidae). J. Hym. Res. 4:137-193.

Page author: John T. Longino

Last modified: 09/16/1996