Pheidole californica

Colonies have been found nesting variously under objects, in oak galls, or in open sandy soil (Cole 1934b; Mallis 1941). Stefan Cover reports a population in moist spots in a grazed Chihuahuan desert at 1295 m in Hidalgo, extreme southwest New Mexico. The colonies were nesting in soil with a high clay content; the most common other ant species was Temnothorax pergandei. (Wilson 2003)

Identification
The Pheidole californica complex comprises three closely related and partly sympatric species of seed harvesting ants restricted to the western Nearctic region. Pheidole clementensis Gregg may be distinguished from both Pheidole californica Mayr and Pheidole creightoni Gregg by the diagonal rather than longitudinal rugulae between the clypeus and the eye in lateral View. The closely related P. californica and P. creightoni are most readily distinguished from one another by the angle of their lateral cephalic setae. Pheidole californica has decumbent setae forming an angle of forty-five degrees or less with the lateral margins of the head in full face view, while the cephalic setae of P. creightoni emerge at an angle of approximately ninety degrees. (Burge, 2005.)

See also the description in the nomenclature section.

Distribution
Pheidole californica is broadly distributed in the western Nearctic region (Burge, 2005); California north to Washington, east to Idaho and New Mexico (Wilson, 2003).

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

Nomenclature

 *  californica. Pheidole californica Mayr, 1870b: 987 (s.w.) U.S.A. Wheeler, W.M. 1915b: 406 (q.); Wheeler, G.C. & Wheeler, J. 1972b: 243 (l.). Senior synonym of incenata, satura: Creighton, 1950a: 173; of pyramidensis: Wheeler, G.C. & Wheeler, J. 1986g: 13; of oregonica (and its junior synonyms hagermani, shoshoni): Wilson, 2003: 564.
 * oregonica. Pheidole oregonica Emery, 1895c: 291 (s.w.) U.S.A. Wheeler, W.M. 1915b: 408 (q.). Subspecies of californica: Wheeler, W.M. 1915b: 407; Creighton, 1950a: 173. Senior synonym of hagermani: Creighton, 1950a: 173; of shoshoni: Gregg, 1959: 19. Junior synonym of californica: Wilson, 2003: 564.
 * incenata. Pheidole californica var. incenata Wheeler, W.M. 1915b: 407 (s.w.) U.S.A. Junior synonym of californica: Creighton, 1950a: 173.
 * nevadensis. Pheidole californica subsp. nevadensis Wheeler, W.M. 1915b: 408 (s.w.q.) U.S.A. [Junior primary homonym of nevadensis Forel, above.] Replacement name: pyramidensis Emery, 1922e: 105.
 * satura. Pheidole californica var. satura Wheeler, W.M. 1915b: 407 (s.w.) U.S.A. Junior synonym of californica: Creighton, 1950a: 173.
 * pyramidensis. Pheidole californica subsp. pyramidensis Emery, 1922e: 105. Replacement name for nevadensis Wheeler, W.M. 1915b: 408. [Junior primary homonym of nevadensis Forel, 1901e: 353.] Junior synonym of californica: Wheeler, G.C. & Wheeler, J. 1986g: 13.
 * hagermani. Pheidole californica var. hagermani Cole, 1936a: 35 (s.w.) U.S.A. Junior synonym of oregonica: Creighton, 1950a: 173.

Description
From Wilson (2003): A member of the “pilifera subgroup” of the larger pilifera group, comprising Pheidole calens, Pheidole californica, Pheidole carrolli, Pheidole cavigenis, Pheidole clementensis, Pheidole creightoni, Pheidole hoplitica, Pheidole littoralis, Pheidole micula, Pheidole pilifera, Pheidole polymorpha, Pheidole rugulosa, Pheidole senex, Pheidole soritis, Pheidole tepicana and Pheidole torosa, which subgroup is distinguished by the following traits. Major: dorsal head surface extensively sculptured; occipital lobes horizontally rugulose (or, in littoralis, foveate, in carrolli, smooth, and in micula and soritis, carinulate); postpetiole from above diamond-shaped, trapezoidal, or spinose. Minor: eye medium-sized to large.

P. californica is distinguished by the following combination of traits. Color yellow.

Major: all of pronotum smooth and shiny; humerus in dorsal oblique view low and smoothly convex; propodeal spine in side view equilaterally triangular; postpetiole from above trapezoidal. Closest to clementensis, from which it differs by its smaller size (HW in californica major about 0.90 mm, in clementensis major about 1.10 mm) and proportionately larger eye (major EL/HW 0.20 in californica versus 0.13 in clementensis). Also, the sides of the major head are smooth and shiny in some, but not all, californica populations (Philip S. Ward, personal communication).

MEASUREMENTS (mm) Major (Palo Alto, California): HW 0.92, HL 1.06, SL 0.54, EL 0.18, PW 0.44. Minor (Palo Alto): HW 0.48, HL 0.56, SL 0.48, EL 0.12, PW 0.28.

COLOR Major: concolorous yellow; gaster a slightly contrasting brownish yellow.

Minor: yellow with a slight brownish tinge.



'''Figure. Upper: major. Lower: minor. CALIFORNICA: Palo Alto. Scale bars = 1 mm.'''

Type Material
- as reported in Wilson (2003)

Type Locality Information
San Francisco. (Wilson 2003)

Etymology
Based on the state of origin of the type series. (Wilson 2003)

Additional References

 * Burge, D.O. 2005. Taxonomy, biology, and distribution of seed harvesting ants in the Pheidole californica complex (Hymenoptera Formicidae). Journal of Hymenoptera Research 14, 137-150.
 * Cole, A. C., Jr. 1934b. An ecological study of the ants of the southern desert shrub region of the United States. Ann. Entomol. Soc. Am. 27: 388–405.
 * Mallis, A. 1941. A list of the ants of California with notes on their habits and distribution. Bull. South. Calif. Acad. Sci. 40: 61–100.
 * Text and images from this publication used by permission of the author.