Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Identification
Minor worker: head length 1.05mm, head width 1.01mm, scape length 1.17mm, Webers length 1.50mm (n=1). Mandibles evenly foveolate; face foveolate and often overlain with coarse rugae; mesosoma weakly to strongly rugose, with underlying sculpture foveolate to shiny; gastral dorsum foveolate; color red-brown to dark brown.
Major worker: head length 2.63mm, head width 2.62mm, scape length 1.27mm (n=1). Hypostomal margin flat with pair of large, blunt teeth; each tooth located about one third distance from midline to small, recessed tooth flanking mandible.
Variation
Minor workers from Corcovado National Park in the southern Pacific lowlands of Costa Rica have the face and mesosoma evenly foveolate, overlain with relatively weak rugae. Specimens from near Monteverde and in the Penas Blancas Valley have the face and mesosoma with coarse, abundant, reticulate rugae, these overlying a largely smooth and shining integument. Specimens from La Selva and elsewhere in the Atlantic lowlands have the coarsely rugose sculpture of Monteverde specimens, but increasing underlying punctation on the mesosoma, like the Corcovado specimens.
Range
Mainland Neotropics from southern Mexico to Amazonian Brazil and Bolivia. Costa Rica: both slopes, to 900m elevation.
Natural History
Pheidole cephalica occurs in wet to moist forest habitats. It nests in dead wood on or near the ground. Workers recruit to dead insects and other baits, and also harvest seeds. Wilson (1987) demonstrated that minor workers were extremely sensitive to the presence of standing water. Even a few drops in the nest of a laboratory colony caused it to immediately evacuate the nest.
Selected Records
Records of workers from La Selva, Braulio Carrillo National Park to 500m, Penas Blancas at 800m, west of Monteverde at 900m, Corcovado National Park.
La Selva: workers taking grubs from a rotten palm inflorescence on the ground.
La Selva: Primary forest along Swamp Trail. A column of workers was carrying seeds to the nest. The nest was in the lower part of a tree trunk lying at the side of the trail. The dead trunk was 20-30cm dia, decomposing, but still solid. The nest was in areas of decaying wood that extended deep into solid wood, so I could only excavate the outer parts of the nest. There were large seed caches inside the nest.
Corcovado National Park (San Pedrillo): Primary forest. Nest under loose bark of a dead but still solid log. Flat chambers under the bark contained workers, some brood, the queen. A few old beetle holes extended into the log; these were filled with brood and callows. I only saw two majors. The colony contained fewer than 100 adults.
Monteverde area: small patch of moist forest west of Monteverde; colony in the hollow core of a dead tree sapling, in an inclined to horizontal section 1-2m high.
Comments
The type locality of cephalica s.s. is Brazil. There are three subspecies, of which two have type localities in Costa Rica: cephalica incrustata Forel 1908 and cephalica sarrita Forel 1908. Wilson (2003) synonymized these under cephalica.
Literature Cited
Wilson, E. O. 1987 ("1986"). The organization of flood evacuation in the ant genus Pheidole (Hymenoptera: Formicidae). Insectes Sociaux 33:458-469.
Wilson, E. O. 2003. Pheidole in the New World: A Dominant, Hyperdiverse Ant Genus. Harvard University Press, Cambridge, Mass
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
Date of this version: 2 September 2003.
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