Dacetini, Myrmicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
Additional images: worker, dorsal view (small, large). Worker from Florida, face view, showing notch anterior to eye (large), lateral view (large).
Pantropical tramp species originating in Africa (Brown 1954). New World distribution: Florida; widespread in West Indies, from Cuba to Trinidad; Guyana; Costa Rica (Atlantic lowlands).
Apical fork of mandible with no intercalary teeth; mandible with two strong preapical teeth; eye bordered anteriorly by a deep notch, clearly visible in face view. Also see Bolton (2000:604).
Head length 0.57-0.62mm, mandible length 0.30-0.34, CI 70-74, MI 53-55 (n=11 workers from 9 localities; Brown 1962).
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).
rogeri is native to Africa but has spread, along with human commerce, to many parts of the globe. It occurs in Hawaii, Fiji, greenhouses in England and Scotland, Florida, and many islands in the Caribbean. In the mainland Neotropics, I know of records from Guyana and the ones reported here for Costa Rica. Nests are in and under dead wood on the ground. Workers preferentially prey on entomobryoid Collembola and Campodeidae, but also take a variety of other small arthropods (Brown 1954).
At La Selva Biological Station, rogeri occurs in leaf litter deep within mature rainforest. Thus, it appears to be one of the few exotics that can invade mature forest, rather than being restricted to synanthropic habitats.
Winkler and/or Berlese samples from La Selva.
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. 1954. The ant genus Strumigenys Fred. Smith in the Ethiopian and Malagasy regions. Bulletin of the Museum of Comparative Zoology 112:3-34.
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.
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.email@example.com
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