Formicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
Additional images: Queen, face view (reduced, original); lateral view of clypeus (reduced, original).
Costa Rica (type locality), Panama, ?Brazil (PE). Costa Rica: northwestern lowlands, Central Valley.
Minor worker: propodeum very narrow and elongate, in cross section tectiform (tent-like, like an inverted "V"), without a distinct angle separating lateral and dorsal faces; clypeus with median longitudinal keel; mesosoma very elongate and narrow in lateral view; side of head lacking erect setae; scapes with no erect setae; color mainly yellow with variably developed black bands on gaster.
This species is a very common inhabitant of dry forest habitats in northwestern Costa Rica and in the Central Valley. The bright yellow workers are a common site at night. They are very opportunistic in nest site selection, and will nest in almost any cavity. They seem to relocate nests quickly and often. In the campground at Santa Rosa National Park, whole nests containing hundreds or perhaps thousands of workers may colonize a backpack or a suitcase overnight. I remember returning to Monteverde after a fieldtrip in Santa Rosa, opening my suitcase, and being startled by an explosion of hundreds of yellow carpenter ants. They grabbed brood and dispersed in all directions. This species once caused serious economic damage in Costa Rica, when colonies occupied boxed fax machines in a warehouse outside of San Jose (Paul Hanson, pers. com.). Paul jokingly called the species Camponotus faxophagus.
I have seen nests being attacked by army ants at Santa Rosa, and could imagine that their rapid and frequent relocation is an adaptation to minimize losses to army ants.
One of the interesting plant species at Santa Rosa is a climbing cactus, Deamia testudo. This cactus snakes along tree trunks and branches, and has swollen sections of stem which tightly clasp the tree surface, forming large chambers underneath. These chambers appear entirely suberized, but roots do extend from the "ceiling." The structure is reminiscent of ant-epiphytes such as Dichidia and Myrmecodia. I once found a large colony of Camponotus zonatus nesting in Deamia chambers. I kept uncovering nests throughout the crown area, and it is likely they were all part of one extended polydomous colony.
I have also found nests in dead wood of various kinds and in bulbous-based myrmecophytic Tillandsia (Bromeliaceae). At both Palo Verde and Estacion Maritza I have found nests under stones. I have found lone queens in various plant cavities, suggesting that founding is solitary and claustral. Nest sites are often in full sun in very open habitats. I have found workers foraging inside of buildings at night, including in the Hotel Aranjuez in San Jose. Although almost all collections have been from open, hot, dry habitats, I do have one collection of workers from a treefall at El Aleman's. This is a montane wet forest site, at 900m elevation on the Atlantic slope just east of Monteverde. Although very different in habitat from the Pacific lowlands, the distance is not great. El Aleman's is only 10km from more typical dry habitats to the west, on the other side of the continental divide.
I have found nests with inquiline cockroaches.
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.email@example.com
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