Pheidole soritis

In eastern Colorado, Gregg (1963) found P. soritis under rocks in the clay soil of cottonwood-willow woodland and shortgrass prairie, from 1000 to 1300 m. I encountered it near Datil, New Mexico, in open juniper woodland (Wilson 1957). A nuptial flight was observed in progress following rainfall on 9 August in an abandoned homesite clearing. The swarms of flying ants, which held resolutely to the clearings, consisted mostly of males. The aggregations were roughly circular in shape and hovered from about half a meter to nearly 2 meters above the surface, depending on wind conditions. Winged queens flew into the swarms and were quickly seized by a male, whereupon the pair spiraled to the ground together. After insemination, the queens shed their wings and ran off over the ground, evidently in search of a nest site. (Wilson 2003)

Identification
The major of this species is small (total length about 2 1/2 mm), the scapes expand about 1/2 way to the posterior lateral corners, the anterior 1/2 of the head is covered with fine, longitudinal rugae, the posterior half is roughly sculptured with longitudinal and transverse striae, the tops of the posterior lateral lobes have transverse striae. The humeral angles and lateral connules are poorly developed. The anterior part of pronotum is predominantly glossy, the posterior part is covered with transverse, but fine striae. The minor worker is a small black ant, in which most of the dorsum of the head is smooth and glossy, the side and top of the pronotum are smooth and glossy, the remainder of the mesosoma punctate. The hairs on the dorsum of the mesosoma are blunt tipped, but not clavate. The minors in our samples show considerable variation in the sculpturing of the head, and in the pronotal rugae, and some of them would key to Pheidole sitarches. (Mackay and Mackay 2002)

Also see the description in the nomenclature section.

Distribution
Mississippi west to Colorado, Texas, Arizona, and northern Mexico. (Wilson 2003)

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

98

Worker
Minor

Nomenclature

 * rufescens. Pheidole sitarches subsp. rufescens Wheeler, W.M. 1908e: 443 (s.w.q.) U.S.A. Junior synonym of campestris: Creighton, 1950a: 189; of soritis: Cole, 1953e: 298; of campestris: Gregg, 1959: 30. [Although both Creighton and Gregg give campestris as the senior name, rufescens has priority: Bolton, 1995b: 329.] Subspecies of sitarches: Bolton, 1995b: 329. Junior synonym of soritis: Wilson, 2003: 598.
 * sitarches. Pheidole sitarches Wheeler, W.M. 1908e: 440 (s.w.q.) U.S.A. Senior synonym of transvarians: Creighton, 1950a: 189; Gregg, 1959: 30. Junior synonym of soritis: Wilson, 2003: 598.
 *  soritis. Pheidole soritis Wheeler, W.M. 1908e: 439 (s.w.) U.S.A. Subspecies of sitarches: Creighton, 1950a: 190. Revived status as species: Cole, 1953e: 298. Junior synonym of sitarches: Cole, 1956c: 115. Revived from synonymy as subspecies of sitarches: Gregg, 1959: 30; Smith, D.R. 1979: 1373. Revived status as species and senior synonym of campestris, rufescens, sitarches, transvarians: Wilson, 2003: 598.
 * transvarians. Pheidole sitarches var. transvarians Wheeler, W.M. 1908e: 442 (s.w.) U.S.A. Junior synonym of sitarches: Creighton, 1950a: 189; Gregg, 1959: 30; of soritis: Wilson, 2003: 598.
 * campestris. Pheidole sitarches subsp. campestris Creighton, 1950a: 189 (s.w.) U.S.A. [First available use of Pheidole sitarches subsp. rufescens var. campestris Wheeler, W.M. 1908e: 443; unavailable name.] Taber & Cokendolpher, 1988: 95 (k.). Junior synonym of soritis: Cole, 1953e: 298. Revived from synonymy as subspecies of sitarches: Cole, 1956c: 115 (footnote); Gregg, 1959: 30. Synonym of rufescens: Creighton, 1950a: 189; Gregg, 1959: 30. [Both references give campestris as senior synonym, but rufescens has priority and is the first available name for this taxon: Bolton, 1995b: 318.] Junior synonym of soritis: Wilson, 2003: 598.

Type Material
NEW MEXICO: Albuquerque. and - as reported in Wilson (2003)

Description
From Wilson (2003): DIAGNOSIS A member of the “pilifera complex” 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 complex is distinguished by the following traits. Major: dorsal head surface extensively sculptured; occipital lobe transversely rugulose (or, in carrolli smooth, in littoralis foveate, and in micula and soritis carinulate); postpetiole from above diamond-shaped, trapezoidal, or spinose. Minor: eye medium-sized to large.

P. soritis is distinguished within this complex by the following combination of traits.

Major: extensive transverse carinulae of occiput curve laterally and forward, with many reaching the anterior border of the head capsule; almost entire dorsal surface of head, including clypeus, carinulate; rugulae lacking on head; humerus low and smoothly convex; postpetiole seen from above laterally angulate; small denticle present on anterior ventral surface of postpetiole in side view.

Minor: dorsal profile of promesonotum lined solely with evenly spaced pairs of clavate hairs; similar hairs occur on the waist; eye very large. The tangled infraspecific nomenclature of this species has been built mostly on variation in the sculpturing of the minor’s head. From central Texas north and west, the posterior dorsal surface is foveolate and opaque (subsp. rufescens = subsp. campestris). To the south, into Mexico, it is smooth and shiny, as illustrated here (subsp. sitarches). Westward to Arizona and Utah it is carinulate (typical soritis). Whether this variation is truly geographic within a single species or reflects the existence of sibling species around sitarches sensu str., is a question that awaits closer field and museum research.

MEASUREMENTS (mm) Lectotype soritis major: HW 1.16, HL 1.22, SL 0.60, EL 0.20, PW 0.52. Syntype sitarches minor (no type soritis minors available): HW 0.46, HL 0.50, SL 0.48, EL 0.12, PW 0.30.

COLOR Major: head and appendages light reddish brown, body a slightly contrasting medium reddish brown.

Minor: body plain light brown, appendages brownish yellow.



'''Figure. Upper: syntype major of synonymous sitarches. Lower: syntype minor of synonymous sitarches. Scale bars = 1 mm.'''

Etymology
Unknown

References based on Global Ant Biodiversity Informatics

 * Alatorre-Bracamontes, C.E. and M Vasquez-Bolanos. 2010. Lista comentada de las hormigas (Hymenoptera: Formicidae) del norte de México. Dugesiana 17(1):9-36
 * Allred D. M. 1982. Ants of Utah. The Great Basin Naturalist 42: 415-511.
 * Allred, D.M. 1982. The ants of Utah. Great Basin Naturalist 42:415-511.
 * Bestelmeyer B. T., and J. A. Wiens. 2001. Local and regional-scale responses of ant diversity to a semiarid biome transition. Ecography 24: 381-392.
 * Cole A. C., Jr. 1956. Observations of some members of the genus Pheidole in the southwestern United States with synonymy (Hymenoptera: Formicidae). Journal of the Tennessee Academy of Science 31: 112-118.
 * Cover S. P., and R. A. Johnson. 20011. Checklist of Arizona Ants. Downloaded on January 7th at http://www.asu.edu/clas/sirgtools/AZants-2011%20updatev2.pdf
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * DuBois M. B. 1985. Distribution of ants in Kansas: subfamilies Ponerinae, Ecitoninae, and Myrmicinae (Hymenoptera: Formicidae). Sociobiology 11: 153-187.
 * Gregg R. E. 1959. Key to the species of Pheidole (Hymenoptera: Formicidae) in the United States. Journal of the New York Entomological Society 66: 7-48.
 * Hess C. G. 1958. The ants of Dallas County, Texas, and their nesting sites; with particular reference to soil texture as an ecological factor. Field and Laboratory 26: 3-72.
 * Johnson R. Personnal Database. Accessed on February 5th 2014 at http://www.asu.edu/clas/sirgtools/resources.htm
 * LeBrun E. G., R. M. Plowes, and L. E. Gilbert. 2015. Imported fire ants near the edge of their range: disturbance and moisture determine prevalence and impact of an invasive social insect. Journal of Animal Ecology,81: 884–895.
 * MacKay W. P. 1993. Succession of ant species (Hymenoptera: Formicidae) on low-level nuclear waste sites in northern New Mexico. Sociobiology 23: 1-11.
 * Mackay W. P., and E. E. Mackay. 2002. The ants of New Mexico (Hymenoptera: Formicidae). Lewiston, New York: Edwin Mellen Press, 400 pp.
 * Mackay, W., D. Lowrie, A. Fisher, E. Mackay, F. Barnes and D. Lowrie. 1988. The ants of Los Alamos County, New Mexico (Hymenoptera: Formicidae). pages 79-131 in J.C. Trager, editor, Advances in Myrmecololgy.
 * Mackay, W.P. and E. Mackay. XXXX. The Ants of New Mexico
 * McDonald D. L., D. R. Hoffpauir, and J. L. Cook. 2016. Survey yields seven new Texas county records and documents further spread of Red Imported Fire Ant, Solenopsis invicta Buren. Southwestern Entomologist, 41(4): 913-920.
 * Moody J. V., and O. F. Francke. 1982. The Ants (Hymenoptera, Formicidae) of Western Texas Part 1: Subfamily Myrmicinae. Graduate Studies Texas Tech University 27: 80 pp.
 * Morrison, L.W. 2002. Long-Term Impacts of an Arthropod-Community Invasion by the Imported Fire Ant, Solenopsis invicta. Ecology 83(8):2337-2345
 * Nash M. S., W. G. Whitford, J. Van Zee, and K. M. Havstad. 2000. Ant (Hymenoptera: Formicidae) responses to environmental stressors in the Northern Chihuahuan Desert. Environ. Entomol, 29(2): 200-206.
 * O'Keefe S. T., J. L. Cook, T. Dudek, D. F. Wunneburger, M. D. Guzman, R. N. Coulson, and S. B. Vinson. 2000. The Distribution of Texas Ants. The Southwestern Entomologist 22: 1-92.
 * Roeder K. A., and D. V. Roeder. 2016. A checklist and assemblage comparison of ants (Hymenoptera: Formicidae) from the Wichita Mountains Wildlife Refuge in Oklahoma. Check List 12(4): 1935.
 * Roeder K. A., and D. V. Roeder. 2017. The Pheidole (Hymenoptera: Formicidae) of Oklahoma: new species records and distributional notes. Check List 13(2): 2071.
 * Smith M. R. 1935. A list of the ants of Oklahoma (Hymen.: Formicidae). Entomological News 46: 235-241.
 * Smith M. R. 1936. A list of the ants of Texas. Journal of the New York Entomological Society 44: 155-170.
 * Taber S. W., and J. C. Cokendolpher. 1988. Karyotypes of a dozen ant species from the southwestern U.S.A. (Hymenoptera: Formicidae). Caryologia 41: 93-102.
 * Torres, I. L., M. A. G. Martinez, H. O. Rivera, M. E. G. Tovar, H. E. L. Espinosa, and J. M. Gonzalez. 2018. Comparacion de dos muestreos de hormigas del suelo en la barranca de Metlac, Fortin de las Flores, Veracruz, Mexico. Revista Cientifica UDO Agricola 10: 173-178.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Warren, L.O. and E.P. Rouse. 1969. The Ants of Arkansas. Bulletin of the Agricultural Experiment Station 742:1-67
 * Wheeler G. C., and J. Wheeler J. 1989. A checklist of the ants of Oklahoma. Prairie Naturalist 21: 203-210.
 * Wheeler W. M. 1908. The ants of Texas, New Mexico and Arizona. (Part I.). Bulletin of the American Museum of Natural History 24: 399-485.
 * Wheeler, G.C. and J. Wheeler. 1985. A checklist of Texas ants. Prairie Naturalist 17:49-64.
 * Wilson E. O. 1958. The organization of a nuptial flight of the ant Pheidole sitarches Wheeler. Psyche (Cambridge) 64: 46-50.
 * Wilson, E.O. 2003. Pheidole in the New World: A Dominant, Hyperdiverse Genus. Harvard University Press
 * Young J., and D. E. Howell. 1964. Ants of Oklahoma. Miscellaneous Publication. Oklahoma Agricultural Experimental Station 71: 1-42.
 * Young, J. and D.E. Howell. 1964. Ants of Oklahoma. Miscellaneous Publications of Oklahoma State University MP-71