Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Identification
Minor worker: head length 0.53mm, head width 0.47mm, scape length 0.45mm, Webers length 0.59mm (n=1). Head somewhat flattened to excavate behind; mesonotal suture very weakly impressed to absent; propodeal spines moderately long, spiniform; face and mesosoma uniformly foveolate; first gastral tergum mat, not shining; dorsal pilosity sparse (about 8 setae on promesonotum), short, stiff; color brown.
Major worker: head length 1.04mm, head width 0.94mm, scape length 0.47mm (n=1). Face largely foveolate, overlain with subparallel, longitudinal rugae on anterior half; vertex lobes smooth and shining, shinyness extending a short distance onto face; clypeus rugose, excavate anteriorly; hypostomal margin gently curved; median tooth rounded, small to absent; pair of stout teeth about one third distance to recessed teeth flanking mandible bases; dorsal pilosity abundant; head with abundant, short setae projecting from sides of head in face view.
Range
Mexico to northern South America, Greater Antilles. Costa Rica: widespread.
Natural History
This species is common in open, disturbed habitats. In Corcovado National Park, it is restricted to the narrow strip of vegetation along the beach (collections from beach edge at San Pedrillo, Llorona, and Sirena, but none from further inland, despite extensive collecting at Sirena, Los Patos, and Los Planes). One nest was observed in a rotten coconut on the ground. In Santa Rosa National Park, a nest was observed under a stone. Near Guacimal, on the road to Monteverde, a nest was observed in a rotten fencepost in full sun. In Monteverde, the species can be an abundant house pest. Workers were collected from a sifted leaf litter sample from the canopy of an emergent Ficus in cloud forest, but these were conceivably contaminants from the house where the Winkler bags were hung. However, workers were collected recruiting to a dead cricket on a road not far from this Ficus. At Fila Cruces, near San Vito, a nest was observed under a stone along a road edge.
Two examples illustrate the synanthropic habitat preference of this species. Workers were collected as pests in the Eladio Cruz house in Penas Blancas, a remote valley east of Monteverde. This species has never been collected in the surrounding clearings or forest, despite extensive collecting. Thus it was probably brought to the house from Monteverde. A similar situation pertains at La Selva Biological Station: the species has been collected as a pest ant entering the ALAS building in the laboratory clearing, but has not been collected in the surrounding forest, in spite of intensive sampling effort.
Longino observed this species in Jamaica. One colony was observed under a bromeliad base on a horizontal dead log. Another was observed in second growth montane forest, under a stone in the trail.
Wilson (2005) observed that P. bilimeki and two other species of small Pheidole (flavens and nebulosa) frequently prey on oribatid mites in the leaf litter.
Comments
Wilson (2003) has a broader concept of bilimeki that includes the species anastasii. See discussion under anastasii. We used to call this species annectens Wheeler 1905, now a synonym of bilimeki.
Literature Cited
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.
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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