Camponotus dumetorum

This ant appears to be the dominant insect of the chaparral. It nests in the ground among the bushes, forming flat craters varying from a few inches to a foot in diameter, with a round or, more frequently, elongate entrance. It does not go abroad in the day time, at least during the dry season. The number of its nests in the chaparral is surprising, but it is difficult to study these, except in places where the brush has been burned over or where it has been c1eared away to leave fire guards. The workers probably derive their sustenance from the aphids and coccids on the scrub-oaks (Quercus dumosa) and other bushes that compose the chaparral. (Wheeler 1910)

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

Nomenclature

 *  dumetorum. Camponotus maculatus subsp. dumetorum Wheeler, W.M. 1910d: 354 (s.w.m.) U.S.A. Combination in C. (Myrmoturba): Wheeler, W.M. 1917a: 560; in C. (Camponotus): Emery, 1925b: 75; in C. (Tanaemyrmex): Creighton, 1950a: 377. Subspecies of sansabeanus: Emery, 1925b: 75. Junior synonym of maccooki: Creighton, 1950a: 377. Revived from synonymy and raised to species: Snelling, R.R. 1970: 396.

Worker
Major Length, 10-13 mm.; head, 3.3 x 3 mm.; scape, 2.5 mm.; hind tibia, 3 mm.

Combining characters of Camponotus maccooki and the typical Camponotus vicinus. Antennal scape not only flattened at the base but dilated to form a lobule which is even larger than that of maccooki and often obtusely angular. Body coarsely shagreened; head and thorax subopaque, gaster slightly shining. Clypeus with several large, elongate, piligerous foveolae; cheeks with more numerous and smaller, elongate foveolae; remainder of head feebly punctate; frontal region with a few deep, piligerous punctures. Hairs and pubescence as in the typical vicinus, yellow, the former absent on the cheeks, erect and abundant on the dorsal and gular surfaces of the head, thoracic dorsum, petiolar border, gaster and flexor surfaces of the femora. Pubescence long but sparse, conspicuous on the head, pleurae, legs and gaster. Head, mandibles, scapes and gaster black; funiculi, legs, thorax, petiole and extreme base of first gastric segment dull brown.

Minor Length, 6-9 mm.

Resembling the worker major, but with the usual differences in the shape of the head, which is often more or less brown like the thorax, especially in front. The lobule at the base of the antennal scape is very large and conspicuous and more angular, so that the scape at this point may be broader than at the tip.

Male
Length, 10-11 mm.

Resembling the male of vicinus, but the head is proportionally shorter and broader, the cheeks are more convex and the scapes are flattened and lobulated at the base. The whole head, especially its, sides and gular surface, is conspicuously hairy. Pleurae, gaster and legs also with numerous, but less conspicuous, erect, tawny yellow hairs. Head and thorax opaque, gaster and legs more shining, but the whole surface densely shagreened. Body black; funiculi and tarsi brown; wings suffused with yellow, with yellow veins and stigma.

Type Material
Described from numerous specimens taken from many colonies in the dry foot-hills of the San Gabriel Range near Pasadena and Claremont, California, up to an altitude of 2,000 feet.

References based on Global Ant Biodiversity Informatics

 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Des Lauriers J., and D. Ikeda. 2017. The ants (Hymenoptera: Formicidae) of the San Gabriel Mountains of Southern California, USA with an annotated list. In: Reynolds R. E. (Ed.) Desert Studies Symposium. California State University Desert Studies Consortium, 342 pp. Pages 264-277.
 * Johnson, R.A. and P.S. Ward. 2002. Biogeography and endemism of ants (Hymenoptera: Formicidae) in Baja California, Mexico: a first overview. Journal of Biogeography 29:10091026/
 * Longino, J.T. 2010. Personal Communication. Longino Collection Database
 * Mallis A. 1941. A list of the ants of California with notes on their habits and distribution. Bulletin of the Southern California Academy of Sciences 40: 61-100.
 * Matsuda T., G. Turschak, C. Brehme, C. Rochester, M. Mitrovich, and R. Fisher. 2011. Effects of Large-Scale Wildfires on Ground Foraging Ants (Hymenoptera: Formicidae) in Southern California. Environmental Entomology 40(2): 204-216.
 * Snelling R. R. 1970. Studies on California ants, 5. Revisionary notes on some species of Camponotus, subgenus Tanaemyrmex (Hymenoptera: Formicidae). Proceedings of the Entomological Society of Washington 72: 390-397.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Ward P. S. 2005. A synoptic review of the ants of California (Hymenoptera: Formicidae). Zootaxa 936: 1-68.
 * Wheeler W. M. 1910. The North American ants of the genus Camponotus Mayr. Annals of the New York Academy of Sciences 20: 295-354.
 * Wheeler W. M. 1917. The mountain ants of western North America. Proceedings of the American Academy of Arts and Sciences 52: 457-569.