Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Range
Mexico to Paraguay (Lattke 1995, Brown 1958). Costa Rica: wet forests of both slopes to 500m.
Identification
Promesonotal suture very faintly impressed, not breaking sculpture; scapes fail to reach margin of vertex when laid back; dorsal surface of mandible smooth and shiny; propodeal dorsum longitudinally striate; anterior margin of anterior apron of clypeus straight or shallowly concave, terminating laterally in sharply rectangular corners; HW greater than 0.73mm; petiolar node longitudinally costulate; meso-metapleural suture well impressed (this character separates regularis from the closely related horni, which occurs from Panama south).
Notes
Gnamptogenys regularis is an arboreal ant in wet forested areas. It may be a specialist predator of other ants: I observed a group raid by regularis on a Pseudomyrmex nest, and I have collected a regularis colony with abundant ant remains in the nest. The related G. horni also has a dietary preference for ants and beetles (Lattke 1990, Pratt 1994).
Pratt studied the biology of G. horni on Barro Colorado Island, Panama. He discovered 7 nests on the forest floor, 6 in Dipteryx sp. seed husks, and one in a small rotten branch. Two colonies were kept in the lab and their behavior observed. One colony contained 9 dealate queens, 67-75 fully pigmented workers, 13-20 callow workers, 4-8 eggs, 35-55 larvae, and 14-14 pupae (ranges reflect variation in daily counts over two to three days). The other contained one dealate queen, 17-18 fully pigmented workers, 22-26 callow workers, 30-40 eggs, 15-25 larvae, and 25-30 pupae. There was evidence of age-based division of labor, with young ants tending brood and older ants foraging. Workers lined the walls of the nest with pieces of old cocoons, a behavior referred to as "wallpapering." There was evidence that the ants used a trail recruitment pheromone in foraging and nest movement. Examination of prey remains in nests showed that G. horni fed principally on a wide variety of ants, but also on other arthopods.
Selected Costa Rican records:
Alajuela: north side Laguna Arenal, 10¡29'N, 84¡44'W, 470m (J. Longino). Roadside vegetation. Nest in Cecropia sapling. Debris in nest was full of ant remains - many head capsules of various myrmicines, Strumigenys, Paratrechina, etc.
Heredia: 15km S Pto. Viejo, 10¡19'N, 84¡02'W, 500m (J. Longino). Roadside vegetation. Nesting in Cecropia insignis sapling.
Heredia: La Selva Biological Station, 10¡26'N, 84¡01'W, 50m (J. Longino).
Limon: 10km ESE Moravia, 9¡48'N, 83¡22'W, 500m (J. Longino). Second growth patches surrounded by tall rainforest. In organic debris in knot of small tree.
Puntarenas: Sirena, Corcovado National Park, 8¡29'N, 83¡36'W, 5m (J. Longino). There was a short column of workers, distinctly linear, 20cm long, moving along a root across the trail. The workers gathered around a hole in a short piece of cut root. They formed a circular formation around what looked like a nest entrance, and appeared to be peering down the hole. I cut into the root, and it was an entrance to a small Pseudomyrmex boopis nest.
Type data
Gnamptogenys regularis Mayr 1870:965. Syntype worker, queen: Mexico.
Literature Cited
Brown, W. L., Jr. 1958. Contributions toward a reclassification of the Formicidae. II. Tribe Ectatommini (Hymenoptera). Bulletin of the Museum of Comparative Zoology 118:175-362.
Lattke, J. E. 1990. Revision del genero Gnamptogenys Mayr para Venezuela. Acta Terramaris 2:1-47.
Lattke, J. E. 1995. Revision of the ant genus Gnamptogenys in the New World (Hymenoptera: Formicidae). Journal of Hymenoptera Research 4:137-193.
Mayr, G. 1870. Neue Formiciden. Verhandlungen der zoologische-botanische Gesellschaft Wien 20:939-996.
Pratt, S. C. 1994. Ecology and behavior of Gnamptogenys horni (Formicidae: Ponerinae). Insectes Sociaux 41:255-262.
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.longinoj@evergreen.edu
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