Ecitoninae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
6 August 1996
Identification (Watkins 1977)
For images, see the very similar Nomamyrmex esenbeckii crassicornis.
Worker: back of head with deep transverse groove (absent in hartigii); top of petiole longitudinally wrinkled (not wrinkled in hartigii); hind margin of mesonotum emarginate (as opposed to straight in crassicornis).
Male: Border of head behind ocellar peduncle with a narrow lamella (absent in hartigii); first gastric tergite usually with longitudinal rugae; width of blade of stipes about one half its length (wider in hartigii); volsellae blunt, gradually tapered or snout-shaped; setae on fifth gastric tergite distinctly separated along the midline (continuous, at least posteriorly, in crassicornis); longitudinal rugae indistinct or absent on second gastric tergite except in sulcus at anterior edge (present in crassicornis).
Geography
Austin, Texas, USA to Costa Rica (Watkins 1977). In Costa Rica, known from Atlantic slope sites (including La Selva, Monteverde).
Natural History
Nomamyrmex esenbeckii wilsoni is in the tribe Ecitoninae, which are the New World army ants. It shares with all army ants the habits of group raiding and colony nomadism. Nomamyrmex esenbeckii wilsoni forages in columns during the day; I do not know if they forage at night. The workers are robust and their columns very conspicuous. The species is uncommon relative to several species of Eciton and Labidus.
I have once observed this subspecies with prey. A column was entering and issuing from fissures in a trail, carrying abundant larvae and pupae of Atta, including pupae of fairly large workers. Also see observations on subspecies crassicornis, which also occurs in Costa Rica and also has been observed attacking Atta.
How to Collect
Visual search for columns in forested habitats or forest edge during the day.
References
Watkins, J. F. II 1977. The species and subspecies of Nomamyrmex (Dorylinae: Formicidae). Journal of the Kansas Entomological Society 50:203-214.
Page author: John T. Longino longinoj@evergreen.edu
Last modified: 08/06/1996