= Pheidole exigua Mayr 1884
Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
Dorsal view of minor worker.
Very widespread in Neotropics: Florida, West Indies, Central America, South America to southern Brazil. Costa Rica: throughout the country to about 1000m elevation.
Minor worker: head length 0.45mm, head width 0.41mm, scape length 0.36mm, Webers length 0.50mm (n=1). Head rounded behind, with median impression; mesonotal suture absent; propodeal spines short; postpetiole globular, little wider than petiole in dorsal view; face and mesosoma uniformly foveolate; first gastral tergum smooth and shining; dorsal setae abundant, medium length, flexuous; color orange.
Major worker: head length 0.80mm, head width 0.75mm, scape length 0.39mm (n=1). Face largely punctatorugose, becoming smooth and shiny on posteriormost face and vertex lobes; weak antennal scrobes present in the form of shallow depressions beneath apices of scapes; hypostomal margin gently curved; median tooth present; lateral teeth pointed, stout, about one third distance from midline to recessed teeth flanking mandible bases (Figure); dorsal pilosity abundant; head with abundant suberect setae projecting from sides of head in face view; postpetiole trapezoidal in dorsal view.
This species is very common and very generalized. It is found in dry forest and wet forest habitats. It is common in Winkler samples and at baits. Nests are found in small cavities (under dead wood on ground, in dead sticks, in dead knots on tree trunks, under bark flaps, under epiphytes) from litter layer to high canopy.
Wilson (2005) observed that P. flavens and two other species of small Pheidole (bilimeki and nebulosa) frequently prey on oribatid mites in the leaf litter.
Wilson (2003) considers there to be two closely related species, flavens and exigua, that have broadly overlapping ranges. The type locality of exigua is French Guiana. The type locality of flavens is Cuba (based on a Neotype designated by Wilson). In the key to the flavens group the two species are distinguished at couplet 129: the edges of the pronotal humeri bear small patches of rugoreticulum in flavens and lack rugoreticulum in exigua. We have not been able to separate Costa Rican material into two species and we treat flavens and exigua as synonyms here.
Wilson, E. O. 2003. Pheidole in the New World: A Dominant, Hyperdiverse Ant Genus. Harvard University Press, Cambridge, Mass
Wilson, E. O. 2005. Oribatid mite predation by small ants of the genus Pheidole. Insectes Sociaux 52:263-265.
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. firstname.lastname@example.org
Stefan Cover, Museum of Comparative Zoology, Harvard University, Cambridge MA 02138 USA. email@example.com
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