Camponotus atriceps is a large reddish brown to black polymorphic ant with lighter coxae and legs, and rather abundant and distinctively flexuous anterior-projecting hairs on its mesosomal dorsum. The species thrives in synanthropic environments, and is considered a household pest (Campos-Farinha, 2005). Records of C. atriceps (and its dozens of junior synonyms) range across the Neotropics from southern South America up into Mexico. A specimen (JTL0000719) was collected by Jack Longino from Texas (Hidalgo Co.) on the Mexican border, and it is unknown whether the locality represents the northernmost extent of its natural range or an introduced population. It is possible that C. atriceps is a complex of closely related species rather than a single species, but more extensive taxonomic and phylogenetic studies will be required before the question is resolved.
Specimens identified as C. atriceps are also reported from Louisiana (Dash, 2004; Dash & Hooper-Bùi, 2008; Dash et al., 2005)and Georgia (specimen code FMNH-INS46082), both of which would likely be introduced populations. However, it is uncertain whether the species referred to in these studies is actually C. atriceps, as it is listed under the Tanaemyrmex subgenus rather than the traditionally applied Myrmothrix, and the diagnosis (attributed to an unidentified Mackay publication) is does not readily match most material of atriceps.
It is possible that the material referred to by Dash and colleagues belongs instead to C. floridanus Buckley. Both species had been considered junior synonyms of C. abdominalis (Hashmi, 1973)before Deyrup et al. (1988)raised C. floridanus to species status. Subsequently, C. abdominalis ( = Formica abdominalis Fabricius) was determined to be the junior homonym of Formica abdominalis Roger (Bolton, 1995). The decision to elevate C. floridanus to species status was supported by the biochemical evidence analyzed by Haak et al. (1996).
The natural history of Camponotus atriceps in Costa Rica has been richly chronicled by Jack Longino, who reports it is extremely widespread in the country, preferring more disturbed habitats to mature forest understory. It is found nesting opportunistically in dead (and occasionally live) wood both arboreally and on the ground, and have been collected from canopy fogging of mature rainforest. The species is considered a house pest in Costa Rica and also in Brazil, where it is known for its damage to honeybee apiaries and its occurrence inside electronic appliances (Campos-Farinha, 2005). Brazilian populations are documented as being polygynous and polydomous (Campos-Farinha, 2005), but no such mention is given to the Costa Rica populations.
The species is considered a house pest in Costa Rica and also in Brazil, where it is known for its damage to honeybee apiaries and its occurrence inside electronic appliances.
Diagnosis of worker among Antkey species. Worker caste polymorphic. Antenna 12-segmented. Antennal club indistinct. Antennal scape length less than 1.5x head length; with many hairs that are longer than the width of the scape. Eyes medium to large (greater than 6 facets). Head of worker lacking distinct ocelli. Antennal sockets and posterior clypeal margin separated by a distance equal to or greater than the minimum width of antennal scape. Head length longer than head width. Dorsum of mesosoma lacking impression such that entire mesosomal dorsal profile forms an unbroken, convex curve. Promesonotum evenly convex, not separated from propodeum by metanotal groove. Propodeum and petiolar node both lacking a pair of short teeth. Propodeum lacking posteriorly projecting protrusion. Metapleuron lacking a distinct gland orifice. Waist 1-segmented. Petiole upright and not appearing flattened. Gaster armed with acidopore. Distinct constriction not visible between abdominal segments 3+4. Erect hairs dense on head, mesosoma and gaster; fine and flexuous, not long thick and produced in pairs.
Camponotus atriceps is diagnosed from other members of the genus introduced or commonly intercepted in the United States by the following characters: (1) metanotal groove not distinctly impressed (versus Camponotus sexguttatus); (2) long erect hairs abundant on head, mesosoma and gaster (versus absent in Camponotus rectangularis and Camponotus variegatus); (3) erect hairs that are fine and flexuous (versus thick and stiff in Camponotus planatus); (4) erect scape hairs longer than scape width (versus shorter in Camponotus planatus); (5) gaster concolorous (versus variegated in Camponotus variegatus).
Native range. Neotropics from southern South America north to Mexico.
Introduced range. (Possibly, see above) USA: Georgia, Louisiana, Texas.