Dacetini, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Line drawing of face view of worker and, at lower right, anterior view of apical fork of mandible (image).
Range
Full Range: throughout mainland tropical America, from southern Mexico to southern Brazil.
Costa Rican Range: Atlantic and southern Pacific lowlands, upper Pacific slope of Cordillera de Tilaran.
Identification
Mandibles in full-face view linear, elongate and narrow; ventral surface of petiole without spongiform tissue; leading edge of scape with freely projecting hairs; inner margin of mandible without a tooth or distinctly enlarged denticle at or near the midlength; labral lobes short, trigger hairs at apices of lobes long; outer margins of mandibles relatively straight; mandibles short and thick, with inner margin convex; close to the apical fork is a small preapical tooth, followed closely by 3-5 smaller denticles; ground pilosity conspicuous and abundant, particularly on head; hairs on head spoon-shaped and reclining. Also see Bolton (2000:193).
Head length 0.48-0.57mm, mandible length 0.26-0.30, CI 82-87, MI 49-54 (n=20 workers, Bolton 2000).
Similar species: gundlachi, eggersi, trieces.
Natural History
Members of the genus are all predaceous, with a static pressure mode of attack (Bolton 1999).
Brown (1960) characterizes the species as follows:
...primarily a species of the leaf litter and upper soil layers in mesic tropical forest. Nests have been found on the underside of a small log buried in leaf litter, in a small pocket in the soil, and among rotting leaves and twigs. In life, the workers are active huntresses ... E. O. Wilson (unpubl. notes) kept a colony from Veracruz alive and gave them a variety of small arthropods, among which they accepted as prey entomobryoid Collembola, while ignoring over two days small millipeds, Reticulitermes nymphs, a small isopod, and an undetermined soft-bodied mite. The colonies so far found have contained from about 20 to 90 workers and one or more queens.
In Costa Rica this species appears relatively common in lowland moist to wet forest on both Atlantic and Pacific slopes. At La Selva Biological Station I observed one colony under a bark flap, low on a tree trunk, and a worker was carrying a collembolan prey item.
Selected Records
Winkler samples from La Selva, road to Monteverde at 900m (islolated patch of evergreen forest in ravine), Carara, Manuel Antonio National Park, Osa Peninsula (Rancho Quemado), Corcovado National Park (Sirena), 19km S Ciudad Neily.
La Selva: night collecting in arboretum; nest under barkflap at base of big Pithecellobium tree; Collembola (prey?) also in collection; a worker seen carrying one at time of collection.
Original Description
Strumigenys subedentata Mayr 1887:570 (in key), 575. Syntype worker: Brazil, Santa Catarina (Hetscko) [NMV, BMNH].
Later moved to Pyramica. See Bolton (2000) for complete synonymy.
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. 1960 (1959). The neotropical species of the ant genus Strumigenys Fr. Smith: Group of gundlachi (Roger). Psyche 66:37-52.
Mayr, G. 1887. Sudamerikanische Formiciden. Verh. K-K. Zool.-Bot. Ges. Wien 37:511-632.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.longinoj@evergreen.edu
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