Dacetini, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Range
Full Range: southern U.S.A. through Central America to Colombia, Trinidad; many Caribbean islands.
Costa Rican Range: open, disturbed habitats in Pacific lowlands and Meseta Central.
Identification
Mandibles in side view straight, not broadly curved ventrally; mandibles relatively short, subtriangular, much of the apical portion meeting along a serially toothed masticatory margin when closed (former Smithistruma); leading edge of scape with a row of conspicuous projecting curved hairs, of which those distal to the subbasal bend distinctly curve toward the base of the scape; pronotal humeral hair absent; dorsal surfaces of middle and hind tibiae with decumbent to appressed short spatulate hairs; color red-brown; face punctate; sides of posterior half of mesosoma completely and densely punctulate; ventral petiolar spongiform appendages entirely obsolete; disc of postpetiole sculptured; gaster with more than 10 erect, somewhat spoon-shaped setae; propodeal teeth slender and acutely tapered, their infradental lamellae obsolete and represented only by fine carinae; basal tergite of gaster finely striolate-punctulate over entire surface, with no or very short coarse striae at postpetiolar insertion. Also see Bolton (2000:221).
Natural History
Members of the genus are all predaceous, with a static pressure mode of attack (Bolton 1999).
This species occurs in open disturbed habitats. Workers can be found foraging on low vegetation, and I have observed them visiting extrafloral nectaries.
I rarely encounter this species because I tend to concentrate my collecting in forested habitats. I have never obtained it by sifting litter. In a study of ant visitors to extrafloral nectaries of Passiflora pittieri at Sirena, Corcovado National Park, I observed many species of ants on thousands of shoots on hundreds of plants. Among these observations, I observed margaritae only twice, both times on shoots of one plant. In another study, collecting ants in scrubby roadside vegetation along the road to Monteverde (120m, La Pita), I found specimens of margaritae in sweep net samples. Finally, I found a worker while collecting in a city park in the middle of San Jose, the capital city of Costa Rica.
Original Description
Strumigenys margaritae Forel 1893:378. Syntype worker, queen, male: Antilles Islands, St. Vincent Island, Palmyra Estate, 1000ft, 3.xi.; Golden Grove Estate, 500ft, ix.; Hermitage Estate, Cumberland Valley, 1000ft, 2.xii (all coll. H. H. Smith) [BMNH, AMNH, MCZ, NMV].
Later moved to Smithistruma, then 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.
Forel, A. 1893. Formicides de l'Antille St. Vincent, recoltees par Mons. H. H. Smith. Trans. Entomol. Soc. Lond. 1893:333-418.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.longinoj@evergreen.edu
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