Pheidole cephalica F. Smith

Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA: Harvard University Press : 674

Pheidole cephalica F. Smith

Pheidole cephalica F. Smith 1858a: 177. Syn.: Pheidole opaca Mayr 1862: 749, synonymy by Kempf 1965: 183; Pheidole opaca var. incrusta Forel 1908c: 59, n. syn.; Pheidole opaca subsp. sacrita Forel 1908c: 59, n. syn.; Pheidole opaca subsp. apterostigmoides Weber 1943b: 71, n. syn.

Types Nat. Hist. Mus. London.

etymology Gr cephalica , of the head, probably alluding to the enlarged head of the major.

diagnosis A very large, small-eyed species, immediately recognizable in the major by the low postpetiolar node in side view, prominent lobose subpostpetiolar process, broad, bell-shaped postpetiole seen from above, and completely foveolate body (including all of the gaster); and in the minor, by the very low petiolar and postpetiolar nodes, cylindrical overall shape of the petiole in side view, extended frontal lobes in dorsal-oblique view, occipital neck, and completely foveolate body (including all of the gaster). Measurements (mm) Major (north of Manaus, Brazil): HW 2.60, HL 2.66, SL 1.26, EL 0.26, PW 1.26. Minor (north of Manaus, Brazil): HW 0.98, HL 1.06, SL 1.12, EL 0.16, PW 0.66. Color Major: body dark reddish brown.

Minor: body light reddish brown except for the gaster, which is yellowish brown.

Range A very widespread species recorded over many localities from Veracruz, Mexico, to Amazonian Brazil and Bolivia, where it is often locally abundant. I have collected it on Tobago, which appears to be its farthest intrusion into the West Indies. In Costa Rica, Longino (1997) reports finding the species from sea level to 900 m.

Biology P. cephalica is an inhabitant of tropical forests, particularly in lowland areas. Colonies nest in rotten logs, stumps, and even the dead branches of standing trees a meter or more off the ground. The minors forage widely over the forest floor and up onto the trunks of standing trees. They feed on insects, are attracted to sugar baits, and also collect seeds. Using laboratory colonies, I demonstrated the extreme sensitivity of minor workers to the appearance of standing water in the nest: at the first sign of potential flooding -even a few drops -the minors initiate trail laying and issue an alarm that causes the colony to evacuate the nest within minutes (Wilson 1987c).

Figure Upper: major. Lower: minor. BRAZIL: 90 km north of Manaus, Amazonas (E. O. Wilson). My drawings were compared with the types of cephalica by Barry Bolton. (Type locality: Tunantins, Amazonas, Brazil.) Scale bars = 1 mm.