Ecitoninae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
7 August 1996
Identification
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Worker: back of head without deep transverse groove (present in esenbeckii complex); top of petiole smooth (longitudinally wrinkled in esenbeckii complex).
Male: Border of head behind ocellar peduncle without a narrow lamella (present in esenbeckii complex); first gastric tergite without longitudinal rugae (present in esenbeckii complex); width of blade of stipes two thirds its length (about half its length in esenbeckii complex); posteroventral projection of volsella triangular with a small dorsal tooth near the sharp apex (volsellae blunt, gradually tapered or snout-shaped in esenbeckii complex).
Geography
Mexico City to southern Brazil (Watkins 1977). In Costa Rica, known from Corcovado and Monteverde.
Natural History
Nomamyrmex hartigii is in the tribe Ecitoninae, which are the New World army ants. It presumably shares with all army ants the habits of group raiding and colony nomadism. This species is much less often seen than members of the esenbeckii complex. My own observations of hartigii are limited to the following:
At Sirena, Corcovado National Park, I observed a nasutiform termite nest on the ground. Thousands of termites had abandoned the nest and were coating the surrounding vegetation. Entire Heliconia leaves had continuous mono-layers of termites. Dolichoderus bispinosus were preying on the termites above ground. I flipped the termite nest and found masses of Nomamyrmex hartigii workers beneath. They had moved into the base from a tunnel and were carrying away termites from several large caches of dead termites.
In Monteverde, at 1400m elevation in the center of the community, I observed a column crossing a hard-packed rock road (near Pension Flor Mar). The column emerged from the ground on one side of the road and disappeared below ground on the other.
These observations suggest that this species is largely subterranean. Thus, even though it is very infrequently collected, little can be said about its absolute abundance.
How to Collect
The few collections are from chance observations of columns. When encountered they are conspicuous, because the colonies are large and the workers robust.
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: 30 June 2007
