Camponotus schaefferi

Camponotus schaefferi nests in dead oak limbs (on living trees) or in the location where a dead branch broke away from the tree, from elevations of 1500 - 2500 meters. One nest was inside living trunk of half-dead Emery oak. A loose female was collected on an oak tree. Workers are very agile and difficult to capture (Mackay and Mackay, 2002; Mackay, 2019).

Compare with Camponotus laevissimus, Camponotus texanus.

Camponotus schaefferi is an unusual member of the subgenus Camponotus. The teeth or angles on the anterior border of the clypeus of the major are well-developed, with the region between the teeth being somewhat concave usually with a medial projection. The sides of the head are nearly parallel, or slightly wider anterior to the eyes, or possibly wider posterior to the eyes. The scapes have scattered erect and suberect setae, but the remainder of the ant has few of these setae that are present on the dorsum of the head, ventral surface of the head, dorsum of the mesosoma, coxae, petiole and gaster; the tibiae have a few suberect setae, especially distally). The anterior face of the petiole is curved back towards the posterior face at the apex. The entire ant is yellowish brown or reddish brown.

The minor worker of C. schaefferi is a relatively small (total length 6 mm) golden brown ant. Most surfaces are smooth and glossy. The head is nearly rectangular shaped, with the sides of the head nearly parallel. The anterior margin of the clypeus has little or no evidence of angles being present, a small triangular region (wider anteriorly) is slightly dented. The scapes extend ½ length past the posterior lateral corner of the head. The clypeus, dorsal and ventral surfaces of the head have a few erect and suberect setae, as does the scape. The dorsum of the mesosoma, petiole, and gaster have several erect and suberect setae.

The female of C. schaefferi is golden brown. The ocelli are well-developed, but small. The anterior medial border of the clypeus is concave, and two angles or teeth are present laterally, similar to those of the major worker. The scape extends slightly more than the first funicular segment past the posterior lateral corner of the head. The dorsoventral surfaces of the head and the scapes have several erect and suberect setae.

The mesosoma, coxae, petiole and gaster have several erect and suberect setae.

The male is unknown.

Comparisons
Camponotus schaefferi is easily separated from all of the other members of the subgenus Camponotus by a combination of having a few erect and suberect setae on the scapes, being concolorous yellowish brown and having the sides of the head of majors, minors and females nearly parallel.

Camponotus schaefferi could be confused with Camponotus laevissimus (distributions overlap in AZ and NM), which has numerous erect setae on the scapes and both species are mostly smooth and shiny, but they are easily separated as C. laevissimus is completely shiny black. Additionally, the angles on the anterior clypeal border of the major and female are much more developed in C. schaefferi than they are in C. laevissimus.

The shiny sculpture and color will separate C. schaefferi from all other New World species of the subgenus, except Camponotus texanus (W Texas). Camponotus schaefferi can be separated from this latter species by color: C. texanus is bicolored, with the head and gaster black, mesosoma red or reddish brown.

This species is found in forests, ranging from scrubby ponderosa pine, Arizona oak, oak pine-juniper woods and oak foothills, especially in the oak Quercus grisea (Mackay and Mackay, 2002).

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

Biology
Sexuals were present in a nest in May and brood were in a nest in September. Workers can be collected foraging on oak trees.

3-octanone and 3-octanol are constituents of the mandibular gland secretions of all castes of Camponotus schaefferi, in which the first functions as a releaser of alarm behavior for workers (Duffield and Blum, 1975). The subgeneric position of C. schaefferi was re-evaluated in terms of this novel mandibular gland chemistry within the genus Camponotus, which is also an unusual compound in the subfamily Formicinae (Duffield and Blum, 1975). Interestingly, 3-octanol is also found in the formicine monotypic Gigantiops destructor (Blum et al., 1983).

They are the host of the endosymbiotic bacterium Candidatus Blochmannia (Degnan et al., 2004) as well as Wolbachia bacteria (Wernegreen et al., 2009).

Nomenclature

 *  schaefferi. Camponotus schaefferi Wheeler, W.M. 1909e: 88 (s.w.q.) U.S.A. Wheeler, W.M. 1910d: 344 (s.). Combination in C. (Myrmentoma): Emery, 1920b: 257; in C. (Camponotus): Forel, 1914a: 266; Creighton, 1950a: 371.

Description
Major worker measurements (mm): HL 2.78 - 3.08, HW 2.78 - 3.14, SL 2.25 - 2.27, EL 0.58 - 0.64, CL 0.96 - 1.14, CW 0.99 - 1.10, WL 3.56 - 3.78, FFL 2.08 - 2.22, FFW 0.76 - 0.81. Indices: CI 100 - 102, SI 73 - 81, CLI 97 - 103, FFI 36 - 38.

Mandible with 5 teeth; anterior border of clypeus concave and with 2 well-defined, blunt teeth, sides of head nearly parallel, usually slightly narrower anterior to eyes, narrowed in region of cheeks, posterior margin slightly concave; eyes failing to reach sides of head by nearly ½ - 1 minimum diameter; scape extending first funicular segment past posterior lateral corner of head; propodeum weakly angulate between 2 faces, dorsopropodeum nearly twice length of posteropropodeum, spiracle elongate; petiole moderately thickened, anterior and posterior faces nearly parallel, convex as seen from front.

Erect and suberect setae sparse on most surfaces, clypeus with 2 setae on posterior margin, scape with few erect or suberect setae, erect and suberect setae along frontal carina extending to posterior margin, posterior lateral corners of head with few small erect and suberect setae, ventral surface of head with numerous erect and suberect setae, mesosoma with few erect and suberect setae, except at angle between faces, numerous setae present on petiole, and gaster with several erect and suberect setae; appressed pubescence sparse and not obvious on any surfaces.

Sculpture on head coriaceous, with scattered, moderately coarse punctures, mesosoma coriaceous, gaster finely, transversely striolate, all surfaces moderately to strongly shining, most surfaces finely sculptured and predominantly smooth.

Concolorous yellowish brown.

Minor worker measurements (mm): HL 1.54 - 2.18, HW 1.26 - 2.02, SL 1.70 - 2.13, EL 0.41 - 0.53, CL 0.44 - 0.73, CW 0.65 - 0.88, WL 2.32 - 3.12, FFL 1.46 - 1.88, FFW 0.49 - 0.65. Indices: CI 82 - 93, SI 98 - 110, CLI 121 - 149, FFI 33 - 35.

Similar to major worker, except sides of head nearly parallel nearly to cheek, eyes nearly reaching sides of head, scape extending almost ½ length past posterior lateral corner of head, pilosity, sculpture and color as in major worker.

Female measurements (mm): HL 2.56 - 2.58, HW 2.50 - 2.52, SL 2.10 - 2.16, EL 0.66 - 0.68, CL 0.86, CW 0.98 - 0.99, WL 4.22 - 4.30, FFL 2.05 - 2.14, FFW 0.69 - 0.70. Indices: CI 98, SI 82 - 84, CLI 113 - 114, FFI 33 - 34.

Similar to major worker, except eyes nearly reach sides of head, scape extends 1 - 2 funicular segments past posterior lateral corner of head, petiole moderately narrow in profile, apex concave or flat as seen from behind; pilosity, sculpture and color as in major worker.

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
 * 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
 * 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
 * Wheeler W. M. 1909. A decade of North American Formicidae. Journal of the New York Entomological Society 17: 77-90.
 * Wheeler W. M. 1910. The North American ants of the genus Camponotus Mayr. Annals of the New York Academy of Sciences 20: 295-354.