Camponotus sayi

In the southwestern part of its range (New Mexico) this species occurs in arid ecosystems where it nests in mesquite (Prosopis spp.) and oaks (Quercus spp.), such as dead limbs (2 - 8 cm diameter) of Quercus arizonica, Q. emoryi and Q. grisea, about 2 meters above soil surface. Dealate females begin nests in such limbs. It is a minor house pest in some areas. Reproductives were found in nests in April. (Mackay and Mackay 2002)

Identification
Major workers of this species have a well defined notch on the anterior border of the clypeus, usually have 2 erect hairs along the basal border of the clypeus, the cheeks and the malar area are without erect hairs, the pronotum is usually without erect hairs, but they may have as many as 4, the dorsum of the mesosoma is very weakly convex, or even straight, the angle of the propodeum is relatively sharp as seen in profile, the petiole is narrow, with sharp apex, the head and mesosoma are usually red, the gaster is black. (Mackay and Mackay 2002)

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

Habitat
In New Mexico (Mackay and Mackay 2002): Chihuahuan Desert, arroyos with hackberry (Celtis), cottonwoods (Populus) in other areas habitats range from prairies to oak-hickory forests, scrubby juniper-pinyon-oak woodland or scrubby ponderosa pine on rocky slopes next to washes, steep, shaded stream banks of seasonal creek valleys with scattered sycamores, walnuts, junipers and large Quercus grisea.

Biology
Nevada, Wheeler and Wheeler (1986) - We have 26 scattered Nevada records from 10 localities. Three records are from the Pinyon-Juniper Biome (but 2 of those are from riparian cottonwood groves). For the remainder no data were given, except that 5 were from houses and 1 under elm bark in Las Vegas and 5 were in houses in Reno. No nests were found.

Nomenclature

 *  sayi. Camponotus sayi Emery, 1893i: 679, pl. 22, figs. 27, 28 (s.w.) U.S.A. Wheeler, W.M. 1910d: 343 (s.w.). Combination in C. (Camponotus): Forel, 1914a: 266; in C. (Myrmentoma): Emery, 1920b: 257. See also: Snelling, R.R. 1988: 72.

Worker
Wheeler (1910) – Major Length, 7-8 mm.; head, 2.5 x 2.4 mm.; scape, 1.7 mm.; hind tibia, 2 mm.

Head large, but little longer than broad, broader behind than in front, with broadly excised posterior margin and prominent posterior corners. Eyes moderately large, feebly convex. Mandibles 5-toothed, convex. Clypeus with very short lateral limbs and subrectangular median portion, which is slightly convex but not carinate, with depressed border and small median notch. Frontal carinae lyrate, rather far apart. Frontal area subtriangular, broader than long. Frontal groove distinct. Antennal scapes short, not reaching the posterior corners of the head, slender and terete at the base, somewhat thickened distally. Thorax stout and short, narrower than the head, robust in front, narrowed and laterally compressed behind; pro- and mesonotum flattened, in profile moderately arcuate; epinotum with subequal base and declivity meeting to form a distinct' though obtuse angle. Petiole high and rather narrow, compressed anteroposteriorly, with convex anterior and flattened posterior surface, its margin entire and rather acute. Legs short, femora stout.

Head and thorax shining, very finely shagreened; cheeks and front with small, round, scattered punctures. Mandibles more coarsely punctate. Gula, sides and posterior corners of head glabrous. Gaster very finely, transversely shagreened, with small, scattered, piligerous punctures, its surface even more shining than the head and thorax.

Hairs white or pale yellow, erect, very sparse; present in a transverse row on the epinotal angle, margin of petiole and in two rows on each gastric segment, one across the middle and the other along the posterior edge. Legs and scapes naked. Pubescence extremely short and dilute, even on the gaster.

Head, antennae, thorax and legs yellowish red; the head slightly darker; gaster black, with the posterior borders of the segments yellow.

Minor Length, 4.5-6 mm.

Head proportionally longer than in the worker major, with straight and more nearly parallel sides, straight posterior border and rounded posterior corners. Clypeus more convex in front, but not carinate, its anterior border with a minute median notch. :Mandibles less convex, eyes more convex than in the worker major, Antennal scapes extending about one-third their length beyond the posterior corners of the head. Thorax less robust; petiole with blunt border.

In sculpture, color and pilosity much like the worker major; head more shining and without small, scattered punctures on the sides and front.

References based on Global Ant Biodiversity Informatics

 * 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
 * Dash S. T. and L. M. Hooper-Bui. 2008. Species diversity of ants (Hymenoptera: Formicidae) in Louisiana. Conservation Biology and Biodiversity. 101: 1056-1066
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Degnan, P.H., A.B. Lazarus, C.D. Brock and J.J. Wernegreen. 2004. Host-Symbiont Stability and Fast Evolutionary Rates in an Ant-Bacterium Association:Cospeciation of Camponotus Species and Their Endosymbionts, Candidatus Blochmannia. Systematic Biology 53(1):95-110
 * DuBois M. B. 1981. New records of ants in Kansas, III. State Biological Survey of Kansas. Technical Publications 10: 32-44
 * Johnson R. Personnal Database. Accessed on February 5th 2014 at http://www.asu.edu/clas/sirgtools/resources.htm
 * Longino, J.T. 2010. Personal Communication. Longino Collection Database
 * 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.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.
 * 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.
 * Snelling, R.R. 1988. Taxonomic notes on Nearctic species of Camponotus, subgenus Myrmentoma (Hymenoptera: Formicidae). pages 55-XX in J. Trager, editor, Advances in Myrmecology
 * Van Pelt, A. 1983. Ants of the Chisos Mountains, Texas (Hymenoptera: Formicidae) . Southwestern Naturalist 28:137-142.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Wheeler G. C., and J. Wheeler. 1986. The ants of Nevada. Los Angeles: Natural History Museum of Los Angeles County, vii + 138 pp.
 * Wheeler, G.C. and J. Wheeler. 1985. A checklist of Texas ants. Prairie Naturalist 17:49-64.