Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Additional images: Queen, face view (small, large); lateral view (small, large).
Range
Costa Rica: mostly Atlantic slope wet to moist forest, to 1100m elevation; also in moist forest on Pacific slope near Monteverde, 1100m elevation.
Identification
Size small; color black; clypeus with moderately diverging carinae, projecting as small teeth; mandible with basal tooth distinct, not widely separated from third tooth; eyes usually large, circular, composed of 5-8 fused ommatidia (occasionally reduced); sparse long setae projecting from vertex margin and sides of head; mesosoma short and compact; petiolar node subtriangular to bluntly rounded; lower portions of katepisternum, propodeum, petiole, and postpetiole punctate. Among the Costa Rican fauna, this is the only small Solenopsis I know with extensive punctate sculpture; all the rest are largely smooth and shining. However, the extent of sculpture is highly variable and can almost vanish. Specimens from higher elevation tend to be larger, darker, with somewhat inflated propodeum, and reduced sculpture on propodeum and petiole. For example, in Winkler samples from Pe–as Blancas there can appear ants that look very different: one with extensive sculpture, lighter color, and subtriangular petiole; another with reduced sculpture, darker color, and more rounded petiole. But these differences are gradually bridged among material from other collections and other localities.
Natural History
This distinctive species occurs in wet to moist forest habitats, in leaf litter on the ground. It is known almost exclusively from Winkler and Berlese samples of forest floor leaf litter. In the Atlantic lowlands it occurs in a high proportion of Winkler samples. I have not collected it in the Pacific lowlands. Chris Thompson carried out a study at La Selva Biological Station, surveying ants nests inhabiting dead wood and dead sticks in the leaf litter. He found two nests of this species, including one with alate queens.
Comments
These may be related to two additional species at La Selva, united by the shape of the head, clypeus, and mandibles; the large multifaceted eyes; and the sparse long setae projecting from the vertex and sides of head. The additional species are JTL-008 and JTL-019. JTL-019 differs in lacking the punctate sculpture and being clear yellow orange to weakly bicolored. JTL-008 is more strongly bicolored and lacks clypeal teeth or ventral postpetiolar tooth. The queen has dense short longitudinal striae around the posterior border of the eye, a character I have not seen in other species.
Literature Cited
Menozzi, C. 1931. Contribuzione alla conoscenza del "microgenton" di Costa Rica. III. Hymenoptera - Formicidae. Bollettino del Laboratorio di Zoologia Generale e Agraria della Reale Scuola Superiore d'Agricoltura. Portici 25:259-274.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.longinoj@evergreen.edu
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