Pheidole bicornis

Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA: Harvard University Press : 641

Pheidole bicornis Forel

Pheidole bicornis Forel 1899e: 74.

Types Mus. Hist. Nat. Geneve.

Etymology L bicornis , two-horned, referring to the cornulate extensions of the frontal lobes of the major.

diagnosis A member of the transversostriata group and evidently close to the tristis group, easily distinguished by its small size; and in the major by the sharp, upturned horn-like extensions of the frontal lobes and heavy rugoreticulate dorsum of the head, broken in the central posterior region by a ladder-like sequence of parallel transverse carinae.

Measurements (mm) Lectotype major: HW 0.86, HL 1.08, SL 0.38, EL 0.12, PW 0.54.

Minor (San Vito, Costa Rica): HW 0.48, HL 0.54, SL 0.42, EL 0.08, PW 0.32.

Color Major: concolorous light reddish brown.

Minor: concolorous yellow.

Range Costa Rica, Panama. In Costa Rica the species has been found in both the Atlantic and Pacific lowlands (Longino 1997) and to an elevation of 1270 m (Risch et al. 1977).

Biology In Costa Rica at least, P. bicornis is an obligate inhabitant of species of understory rainforest shrubs of the genus Piper. The ants live in cavities of the petioles and stems that they hollow out themselves. The relationship appears to be mutualistic: the workers, which seldom forage on the ground, feed on lipid-rich food bodies developing within the petiolar cavities. For their part the plants evidently benefit from the removal of the eggs and early stages of herbivorous insects (Letourneau 1983), as well as from the clearing of vines and transport of organic material into the plant by the ants during nest construction (Risch et al. 1977).

Figure Upper: lectotype, major (Bugaba, Panama). Lower: minor (Finca Loma Linda, near Agua Buena, Puntarenas, Costa Rica, J. Vandermeer). Scale bars = 1 mm.