Pheidole ceres

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 (1986) 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 Pheidole 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. (Wilson 2003)

Identification
Mackay and Mackay (2002) - This is a small species (majors < 2.5 mm total length). Most of the head is striate, only the posterior part of the head and the tops of the posterior lateral lobes are shining. The mesosoma is predominantly punctate, the side and top of the pronotum are smooth and shining. The lateral connules of the postpetiole are weakly formed, but present. The dorsal surface of the gaster is smooth and glossy. The scapes extend about half of the length of the head. The scapes of the minor worker extend about one funicular segment past the posterior lateral corners, the dorsum of the head is nearly completely glossy, the side as well as the top of the pronotum are smooth and glossy, much of the remainder of the mesosoma is densely, and coarsely punctate. The major and minor are generally dark brown. The sculpture of the dorsum of the head of the major worker generally separates it from all other species. It could be confused with Pheidole marcidula, but can be separated, as the minors do not have clavate hairs on the dorsum of the mesosoma.

Also see the description in the nomenclature section.

Distribution
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 1950: 174), and from Guerrereo Mills, in the mountains of Hidalgo (tepaneca types). (Wilson 2003)

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Mexico.



Habitat
Mackay and Mackay (2002) - Ponderosa pine, ponderosa pine-riparian, Gamble oak, highly disturbed areas, including burned areas, between 1500 - 2,800 meters. It is also found in pinyon-juniper and sagebrush communities in northern New Mexico, often on south-facing slopes.

Nomenclature

 *  ceres. Pheidole ceres Wheeler, W.M. 1904a: 10 (s.w.q.m.) U.S.A. Senior synonym of tepaneca: Wilson, 2003: 570.
 * tepaneca. Pheidole ceres subsp. tepaneca Wheeler, W.M. 1914b: 46 (s.w.q.) MEXICO. Junior synonym of ceres: Wilson, 2003: 570.

Description
From Wilson (2003): DIAGNOSIS A member of the “bicarinata complex” of the larger pilifera group, comprising Pheidole agricola, Pheidole aurea, Pheidole barbata, Pheidole bicarinata, Pheidole centeotl, Pheidole cerebrosior, Pheidole ceres, Pheidole defecta, Pheidole gilvescens, Pheidole macclendoni, Pheidole macrops, Pheidole marcidula, Pheidole paiute, Pheidole pinealis, Pheidole psammophila, Pheidole xerophila, Pheidole yaqui and Pheidole 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.



'''Figure. Upper: lectotype, major. Lower: paralectotype, minor. Scale bars = 1 mm.'''



Type Material
COLORADO: Colorado Springs, col. W. M. Wheeler, - as reported in Wilson (2003)

Etymology
L Ceres, the pre-Roman goddess of agriculture, evidently in reference to the seed-harvesting practiced by the species. (Wilson 2003)