Pheidole ceres Wheeler

Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA: Harvard University Press : 570

Pheidole ceres Wheeler

Pheidole ceres Wheeler 1904a: 10. Syn.: Pheidole ceres subsp. tepaneca Wheeler 1914c: 46, n. syn.

types Mus. Comp. Zool. Harvard.

Etymology L Ceres, the pre-Roman goddess of agriculture, evidently in reference to the seed-harvesting practiced by the species.

diagnosis A member of the " bicarinata complex" of the larger pilifera group, comprising agricola , aurea , barbata , bicarinata , centeotl , cerebrosior , ceres , defecta , gilvescens , macclendoni , macrops , marcidula , paiute , pinealis , psammophila , vinelandica , xerophila , yaqui , and yucatana , which complex is characterized by the large to very large, forward-set eyes, especially in the minor; and in the major, the occipital lobes lacking any sculpturing (except in aurea ); the posterior half of the head capsule almost entirely smooth and shiny; and the postpetiolar node seen from above oval, elliptical, or laterally angulate (cornulate in cerebrosior ). P. ceres is distinguished within the complex by the following combination of traits. Dark to blackish brown. Major: carinulae originating on the frontal triangle travel along the midline to the occiput; transverse carinulae present along the anterior lateral margins of the pronotum; mesonotal convexity and propodeal spines well-developed; postpetiole from above laterally angulate and diamond-shaped.

Minor: eyes moderately large; mesonotal convexity low but well-developed. Measurements (mm) Lectotype major: HW 1.14, HL 1.18, SL 0.66, EL 0.16, PW 0.54. Paralectotype minor: HW 0.54, HL 0.60, SL 0.54, EL 0.12, PW 0.34.

Color Major: body blackish brown, with brownish yellow clypeus; appendages brownish yellow to medium brown. Minor: like the major, except that the clypeus is not yellow but dark brown and hence not contrasting.

Range Foothills of the Rockies in eastern Colorado at 1800-2600 m, southwest to the mountains of New Mexico and Arizona, at 2200-2700 m, as well as extreme eastern Nevada. Also recorded from the Davis Mts. of Texas but evidently rare there (Creighton 1950a: 174), and from Guerrereo Mills, in the mountains of Hidalgo ( tepaneca types).

biology According to Stefan Cover, ceres is found at higher elevations and in colder climates than any other Pheidole species in the western North American fauna. In southern Arizona it is often the only Pheidole occurring above 2250 m. Gregg (1963) reports ceres to be the most abundant Pheidole in Colorado, where it occurs in a wide array of habitats, including ponderosa pine forest, foothills meadowland, and sagebrush. Cover found the species in the same general habitats in Arizona and New Mexico. In Nevada G. C. and J. Wheeler (1986g) found a colony at 2650 m in juniper-pinyon woodland. The ants collect and store seeds of a variety of grasses and herbaceous angiosperms. P. ceres nests in several types of open soil under rocks. Colonies are large and active, consisting of up to 1000 ants. Majors are numerous and most colonies are monogynous. P. ceres is also notable as the host of the workerles parasite P. elecebra . Winged sexuals have been found in nests principally from early to the middle of July, with one record of males on 9 September. Winged reproductives have been found in nests throughout July, and a wingless queen was collected on 21 July, presumably following a nuptial flight.

Figure Upper: lectotype, major. Lower: paralectotype, minor. COLORADO: Colorado Springs (W. M. Wheeler). Scale bars = 1 mm.