Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Identification
Minor worker: head length 0.43mm, head width 0.42mm, scape length 0.35mm, Webers length 0.47mm (n=1). Head flattened behind, shallowly excavate; mesonotal suture absent; in profile, rear margin of promesonotum and dorsal face of propodeum forming an obtuse angle; propodeal spines moderately long, spiniform; face uniformly foveolate; pronotum smooth and shining; propodeal dorsum smooth and shining; katepisternum foveolate around margins, smooth and shining medially; side of propodeum foveolate dorsally, smooth and shining ventrally; first gastral tergum smooth and shining; dorsal pilosity sparse, moderately long, flexuous; color orange.
Major worker: head length 0.85mm, head width 0.69mm, scape length 0.36mm (n=1). Face foveolate throughout, overlain with subparallel, longitudinal rugae anteriorly, faint reticulate rugae posteriorly; antennal scrobes weakly present as shallow depressions beneath apices of scapes; hypostomal margin gently curved, with conspicuous median tooth, and a pair of similar sized teeth about one half distance from midline to recessed teeth flanking mandible bases (Figure); dorsal pilosity abundant; head with abundant, short, suberect setae projecting from sides of head in face view.
Range
Costa Rica (Atlantic slope to 1000m).
Natural History
Inhabits wet forest leaf litter; nests in soil or in dead wood on ground.
Selected Records
La Selva: Winkler samples.
Braulio Carrillo National Park: Winkler samples from 800-1000m.
Braulio Carrillo National Park (observation by Longino): 1100m elevation; dense, shaded second growth, mostly Cephaelis, along a stream bank. I watched a Simopelta raid on a Pheidole colony. A column of Simopelta workers extended from the leaf litter on one side of the trail, across the trail to a spot on the opposite bank. There the column ended at a spot where workers clustered. There was no superstructure to the Pheidole nest, and at first I saw no reason for the aggregation. After a few minutes, an alate Pheidole queen was pulled from a small hole and attacked. Soon thereafter, several other queens emerged, and some minor workers. Later a major worker appeared. All were attacked. For about 5 minutes the captive adults were pinned near the entrance to the nest. Rather suddenly, Simopelta workers began extracting brood from the nest, and the raiding column began to return. Brood, workers, and the alates were all carried away. The column disappeared into the leaf litter about 1m from the Pheidole nest, and I could not trace it beyond that point.
Penas Blancas Valley: Common in Winkler samples. Nest in dead stick lying on ground.
Guanacaste Conservation Area (Pitilla): Winkler sample.
Page authors:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
Stefan Cover, Museum of Comparative Zoology, Harvard University, Cambridge MA 02138 USA. scover@oeb.harvard.edu
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