Dacetini, Myrmicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Additional images: worker, dorsal view (small, large).
Range
Costa Rica, USA. In Costa Rica: mid-elevation Atlantic and Pacific slopes, Cordillera Volcanica Central northward.
Identification
Apical fork of mandible with one intercalary tooth; mandible with acute preapical tooth very close to apical fork, and sometimes a minute denticle near the apical third of mandible length; gaster smooth and shining, with setae stiff, straight, slightly thickened. See also Bolton (2000:517).
Head length 0.61-0.63mm, mandible length 0.36-0.38, CI 77-80, MI 58-60 (n=8 workers from 1 locality; Brown 1962).
line drawing of worker face (from Brown 1962)
Similar species: micretes, diaptyxis.
Brown (1959, 1962) differentiates the Mexican emeryi from the Costa Rican nevermanni by the latter lacking a preapical denticle proximal to the preapical tooth. I find this character variable in Costa Rican material.
Natural History
Brown and Wilson (1959) summarize the genus as follows:
"Widespread in tropics and warm temperate areas. Primarily forest-dwelling; some species occur in grassland and arid scrub. ... Nests mostly in soil and rotting wood; a few species live in arboreal plant cavities in tropical rain forest. Foraging hypogaeic to epigaeic-arboreal. Food: most species are collembolan feeders; a few are polyphagous predators or occasionally feed on sugary substances..."
Members of the genus are all predaceous, with a kinetic mode of attack (Bolton 1999).
In Costa Rica, nevermanni occurs in wet forest habitats. It nests and forages in the low arboreal zone and in some cases in litter on the forest floor.
The lone USA record is curious. I was collecting from cynipid oak galls near Austin, Texas, many of which were inhabited by nests of Camponotus etiolatus and C. discolor. In one nest of C. discolor, I also found three workers of S. nevermanni.
Selected Records
Braulio Carrillo National Park (Bajo la Hondura): This is the type locality of nevermanni, based on specimens collected by Nevermann. I also collected at this site, and found a nest in a knothole under a moss mat on a small live tree.
Guanacaste Conservation Area (Pitilla): wet forest. Under loose bark in treefall.
Penas Blancas Valley: wet forest. Nesting in small rotten knot in live shrub at edge of clearing.
Winkler samples from two sites in and near Monteverde, at 1300 and 900m on the Pacific slope.
Literature Cited
Bolton, B. 1999. Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae). J. Nat. Hist. 33:1639-1689.
Bolton, B. 2000. The ant tribe Dacetini, with a revision of the Strumigenys species of the Malagasy Region by Brian L. Fisher, and a revision of the Austral epopostrumiform genera by Steven O. Shattuck. Memoirs of the American Entomological Institute 65:1-1028.
Brown, W. L., Jr. 1959. The Neotropical species of the ant genus Strumigenys Fr. Smith: Group of emeryi Mann. Entomological News 70:97-104.
Brown, W. L., Jr. 1962. The neotropical species of the ant genus Strumigenys Fr. Smith: Synopsis and keys to the species. Psyche 69:238-267.
Brown, W. L., Jr., Wilson, E. O. 1959. The evolution of the dacetine ants. Quarterly Review of Biology 34:278-294.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.longinoj@evergreen.edu
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