Dacetini, Myrmicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Additional images: worker dorsal view.
Range
Widespread, from southern Mexico south to Brazil and Paraguay. Costa Rica: both slopes to 500m.
Identification
Apical fork of mandible with a single intercalary tooth; mandible with two conspicuous preapical teeth; mandible extremely long, longer than head; gaster smooth and shiny; specialised humeral hair stiff and freely projecting, approx. straight or nearly so, simple or slightly expanded apically (lacking in deletrix); dorsolateral margin of the head close to the apex of the scrobe with stiff projecting hair present (lacking in deletrix). Also see Bolton (2000:531).
Head length 0.73-0.82mm, mandible length 0.83-0.92, CI 76-80, MI 109-123 (n=40 workers from 8 localities; Brown 1962).
Similar species: deletrix
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..."
Brown (1958) states that the extremely long mandibles of cordovensis are possibly used
"to lift the prey, presumed to be mainly or entirely furculate collembolans as in other species of the genus, clear of the ground after the mandibular strike is made, in this way preventing the springtails from kicking with the furcula against the ground and upsetting the ant. Such disproportionately large mandibles must be employed almost entirely in the open, because confined spaces would surely hinder their action."
However, Bolton (1999) has shown that all members of the genus use a kinetic mode of attack, in which the prey is stunned prior to grasping and lifting. This suggests that the long mandibles of cordovensis simply give the species a greater striking power and reach, rather than allowing struggling prey to be lifted clear of the ground.
In Costa Rica this species occurs in dry and wet forest habitats. It inhabits forest floor leaf litter.
Selected Records
Winkler samples from Turrialba, La Pacifica, Carara.
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. 1958. The neotropical species of the ant genus Strumigenys Fr. Smith: Group of cordovensis Mayr. Studia Entomologica 1:217-224.
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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