Neivamyrmex pilosus mexicanus (Fr. Smith 1859)

Ecitoninae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view

male face view

male lateral view


Throughout mainland Neotropics and subtropics, from southern United States (Arizona, Texas) to Bolivia and northern Argentina. Costa Rica: Atlantic and southern Pacific lowlands, Cordillera de Tilarán (San Luis Valley).


Posterior face of propodeum straight, not concave, about as long as dorsal face; eye with distinct convex cornea; color dark red brown to black.

Natural History

This is the most commonly encountered species of Neivamyrmex in Costa Rica. It is the only species routinely seen raiding during the day. The columns of black, shiny workers that are relatively uniform in size distinguish them from other diurnally raiding army ants. The workers have a strong foetid odor. I have often seen raiding columns ascending and descending canopy trees. Caches of prey brood may be found under bark flaps and under leaf litter along the columns. Prey brood are usually Crematogaster or Azteca. These observations suggest that N. pilosus is a specialist on arboreal ants.

While collecting in Venezuela, I once observed a column of N. pilosus raiding Azteca in a Cecropia peltata tree that had been pushed over by logging activity.

Males are common at lights. The ALAS project carried out an 18-month program of sampling using blacklight traps. Males of N. pilosus were only obtained in the months of March, April, and May. These are the months of late dry season to early wet season.

Page author:

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

Date of this version: 14 July 2005.
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