Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Image catalogue, worker from Penas Blancas (click here).
Image catalogue, worker from Barva Transect, 1070m site (click here).
Range
Ecuador, Panama, Costa Rica. In Costa Rica known from Hitoy Cerere, the Penas Blancas Valley (Eladio's at 800m), La Selva Biological Station, and the Barva transect at the 1070m site.
Identification
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.
Of the few known specimens from Costa Rica, one is very small (figure). The ALAS Project collected a specimen from the Volcan Barva transect that was very much smaller than the other specimens and with fewer, proportionally broader facial costae. At first I thought it was a distinct species, but all characters other than size matched banksi.
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 seen four 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, 3) a worker in La Selva in 1996, and 4) a worker from a Winkler sample at the 1070m site on the Volcan Barva transect.
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 decade, 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.
Type data
Emeryella (Barbourella) banksi Wheeler 1930:10. Holotype queen: Panama.
Literature Cited
Lattke, J. E. 1995. Revision of the ant genus Gnamptogenys in the New World (Hymenoptera: Formicidae). J. Hym. Res. 4:137-193.
Wheeler, W. M. 1930. A new Emeryella from Panama. Proceedings of the New England Zoological Club 12:9-13.
Page author: John T. Longino longinoj@evergreen.edu
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