Camponotus vicinus

Nest chambers are often under a stone or, less frequently, under downed wood.

Identification
The majors, minors, and females of this species have the area at the base of the scape flattened, which is rarely enlarged into a poorly formed lobe. The frontal carinae are widely separated. The cheek, malar area, and sides of head are nearly always without erect hairs, but up to 3 for 4 hairs may be present on the cheeks (usually located near the base of mandibles), and an erect hair on the ventral surface of the head may be visible in full face view, appearing as an erect hair on the side of the head. The mesosoma has numerous erect hairs, as does the petiole and the gaster, the hairs on the gaster are positioned along the posterior edge of each tergum, as well as nearly always scattered across the surface. The middle and hind tibiae have 2 rows of erect, coarse hairs that extend nearly the entire length of the tibiae, but there are usually fewer than 10 present, and most are on the distal half. The head and mesosoma have a few appressed hairs. The appressed hairs on the gaster are variable, ranging from a few tiny (0.01 mm) hairs, to coarse, long (up to 0.2 mm) hairs. The head is densely and evenly punctate, the mesosoma is coriaceous, and the gaster ranges from smooth and glossy to dull with coarse transverse striae. The color ranges from yellow brown to black, the most common color includes a black head and gaster with a red mesosoma and legs. (Mackay and Mackay 2002)

Distribution
Southwestern Canada, western United States, south to northwestern Mexico.

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

Habitat
In New Mexico (Mackay and Mackay 2002): Chihuahuan Desert, areas of mesquite, sagebrush, meadows, deciduous forests, oak forests, riparian cottonwood forests, ponderosa pine-riparian, pinyon-juniper, ponderosa pine, Douglas fir, aspen forest, usually at higher elevations in relatively mesic sites (1930 - 2960 meters).

Biology
Wheeler (1910) - C. vicinus live in the soil under stones in rather dry, sunny places. The eggs and young larvae are of a peculiar salmon-yellow color. The sexual phases seem to occur in the nests at all times of the year.

For New Mexico (Mackay and Mackay 2002) - This is a very common species in New Mexico, which nests under stones and logs (rare) in open areas of fine sand to rocky soils. Brood and reproductives were found in nests from March to October, dealate females were captured from March to mid September. A flight occurred on 19-vii-1986 at 7:00 p.m. Nests are occasionally started by pleometrosis (multiple females start nests together). Much of the foraging occurs at night, although workers are also diurnal; workers tend Homoptera. Workers forage into vegetation, especially cholla (Opuntia sp.), and Yucca sp. Workers are attracted to baits, including liver, especially rotten liver. Monomorium minimum, Myrmica striolagaster, Liometopum apiculatum, Leptothorax crassipilis, and Solenopsis live in nests. One nest inhabited an abandoned nest of Pogonomyrmex occidentalis. Gynes are prey of Formica and Solenopsis.

In the Bitterroot Mountains of Montana these ants can be common in open meadows. A single colony can have nest chambers under numerous rocks.

Nevada, Wheeler and Wheeler (1986) - This is one of the commonest and most widely distributed of all Nevada ants. There are two main color phases: one is pale and in the field cannot be distinguished from Camponotus semitestaceus; it occurs in arid and semiarid habitats. We have 197 records in Nevada from 141 localities; 3,900-9,700 ft. Twenty-eight records are from the Cool Desert (including 1 from a Sarcobatus Subclimax, 1 from a cottonwood grove, and 2 riparian), 74 are from the Pinyon-Juniper Biome, and 37 from the Coniferous Forest. The majority (65) of nests were under stones; 9 were under rotten logs lying on the ground; 12 were exposed with excavated soil around the entrance (which sometimes could be called a crater). Entrances ranged from 5 to 30 mm in diameter. Xenodusa angusta Fall (Coleoptera: Staphylinidae; det. RR Snelling) was a guest in a nest. C. vicinus workers were tending waxy scales, Orthezia nigrocincta Cockerell (Homoptera: Ortheziidae; det. D.R Miller), on the roots of Sarcobatus vermiculatus.

Nomenclature

 *  vicinus. Camponotus vicinus Mayr, 1870b: 940 (w.) U.S.A. Emery, 1893i: 671 (s.q.); Wheeler, W.M. 1910d: 301 (m.); Wheeler, G.C. & Wheeler, J. 1968: 220 (l.). Combination in C. (Myrmoturba): Forel, 1914a: 268; in C. (Camponotus): Emery, 1925b: 75; in C. (Tanaemyrmex): Creighton, 1950a: 381. Subspecies of sylvaticus: Mayr, 1886d: 422; of maculatus: Emery, 1893i: 671; of sansabeanus: Emery, 1920b: 232 (footnote); Cole, 1942: 387. Revived status as species: Creighton, 1950a: 381; Snelling, R.R. 1970: 396. Material of the unavailable names infernalis, luteangulus, maritimus, nitidiventris, plorabilis, subrostrata referred here by Creighton, 1950a: 381; material of the unavailable name berkeleyensis referred here by Snelling, R.R. 1970: 396.

Worker
Wheeler (1910) – Major Length, 11-13 mm; head, 3.7 x 3.5 mm.; scape, 3.2 mm.; hind tibia, 3.3 mm.

Head, excluding the mandibles, nearly as broad as long, broader behind than in front, with feebly concave posterior and feebly convex lateral borders, convex dorsal and flattened gular surfaces. Mandibles strong, convex, 6-7-toothed. Clypeus carinate, its anterior border moderately produced in the form of a broad flap like lobe with rounded corners and crenate edge. Frontal carinae lyrate. Eyes moderately large, flattened. Antennal scapes distinctly flattened at the base and but slightly widened at their tips, which reach a short distance beyond the posterior corners of the head. Thorax robust in front though narrower than the head; pro- and mesonotum slightly flattened; meso- and metapleural regions compressed; in profile, the dorsum is evenly arched, the epinotum with subequal base and declivity, forming at their juncture a rounded, obtuse angle. Petiole with convex anterior and flattened posterior surface and rather blunt border. Gaster of the usual shape. Legs long; middle and hind tibiae elliptical in cross-section, neither compressed nor grooved.

Mandibles and anterior borders of cheeks shining, the former very coarsely striato-punctate; head, thorax and gaster subopaque; head densely shagreened behind, in front very densely and finely punctate or granular, sides also with numerous smail rounded foveolae; sides of clypeus and inner borders of frontal carinre with a few large piligerous foveolae. Thorax, petiole and legs more finely, gaster more coarsely and transversely shagreened, also with small transverse foveolae bearing the pubescence and large piligerous foveolae across the middle and along the posterior border of each segment.

Hairs and pubescence yellow, the former long, sparse and erect, confined to the mandibles, clypeus, dorsal surface of head, thorax, border of petiole, gula and both dorsal and ventral surfaces of the gaster. Pubescence sparse, especially on the gaster, but very distinct on the posterior portions of the head, thoracic dorsum, scapes, and legs. Middle and hind tibiae with rows of stiff, graduated bristles on their flexor surfaces. There are a few short hairs at the tips of the antennal scapes and at the femoro-tibial articulations.

Head and antennal scapes black; mandibles, clypeus, cheeks and antennal funiculi often tinged with red. Thorax and legs brownish red or chestnut; gaster black, with dull brown posterior segmental margins; base of first segment or the whole of the first and second segments red like the thorax.

Minor Length, 7-8.5 mm.

Head longer than broad, not contracted but rounded behind the eyes, with rather straight, subparallel sides. Clypeus and antennal scapes much like those of the worker major, the scapes reaching nearly half their length beyond the posterior corners of the head. Thorax about as broad as the head, base of the epinotum somewhat longer than the declivity. Petiole subcuneate, with more convex posterior surface and blunter border than in the worker major.

Sculpture, pilosity and color much as in the worker major, but gaster not red at the base.

Queen
Wheeler (1910) - Length, 14-16 mm.

Head similar to that of the worker major but proportionally longer and narrower behind, with more nearly parallel sides. Thorax about as broad as the head. Epinotum with short, convex base and much longer, steep and slightly concave declivity. Petiole rather high, thick below, compressed anteroposteriorly above, with sharp border. Wings long (16-17 mm.).

Differs from the worker major in sculpture to the extent of having the thorax, gaster, legs and lower lateral borders of the head shining.

Pilosity, pubescence and color much as in the worker major, but the mesonotum, scutellum and metanotum black and .the pronotum, pleurae, tibiae and femora sometimes infuscated. Gaster frequently red at the base. In some specimens, the whole of the thorax and the legs are very dark brown or black. Wings suffused with brown; veins and stigma light brown.

Male
Wheeler (1910) - Length, 8-11 mm.

Head somewhat longer than broad, with large, convex eyes, broader and rounded postocular region and concave cheeks. Clypeus carinate, with broadly rounded anterior border. Mandibles edentate. Antennal scapes slender, terete, not flattened at the base. Thorax robust; epinotum like that of the female, Petiole very low and thick, its upper border transverse, blunt, sometimes with a broad but shallow excision.

Head, thorax and gaster very finely shagreened, shining.

Pilosity much as in the worker; pubescence shorter and much less conspicuous.

Black; mouthparts, funiculi, genitalia, tarsi and articulations of the legs and wings brownish or reddish. Wings colored like those of the female.