|Junior synonym of Camponotus abdominalis: Roger, 1862c PDF: 285; Santschi, 1913h PDF: 42; Hashmi, 1973b: 83.|
|Oldest synonym of, and hence first available replacement name for, Formica abdominalis Fabricius, 1804: 409, designated by Bolton, 1995b: 86.|
|Junior synonyms attached to Camponotus abdominalis Fabricius by Hashmi, 1973b: 82-83 are transferred to Camponotus atriceps, which hence is senior synonym of: Camponotus atricipitoesuriens, Camponotus costaricensis, Camponotus cupiens, Camponotus depressidens, Camponotus epistomatus, Camponotus esuriens (and its junior synonym Camponotus vulpinus), Camponotus fuchsae, Camponotus fulvacea, Camponotus fumata, Camponotus laevilata, Camponotus mediopallidus, Camponotus rabidus, Camponotus romani, Camponotus stercorarius, Camponotus taeniatus, Camponotus transvectus, Camponotus ustulatus.|
|Material of the unavailable names Camponotus defrictus, Camponotus flavobasalis, Camponotus luisae, Camponotus misionensis, Camponotus panamanus, referred to Camponotus abdominalis Fabricius by Hashmi, 1973b: 82, is here referred to Camponotus atriceps.|
|Current subspecies: nominal plus Camponotus atriceps nocens.|
|(status uncertain, see Hashmi, 1973b: 120).|
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 enviorments, 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.
Native Range. Throughout mainland Neotropics.
Introduced Range. Unknown, but possibly Texas. Records from Louisiana (Dash, 2004; Dash & Hooper-Bi, 2008; Dash et al., 2005) and Georgia (specimen FMNH-INS46082) are unconfirmed.
Costa Rica: throughout country below cloud forest elevations.
Specimens identified as C. atriceps are also reported from Louisiana (Dash, 2004; Dash & Hooper-Bi, 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 (see below), 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.In Costa Rica (Jack Longino)
Workers are typically nocturnal foragers. Similar to most Camponotus, workers are quite timid as isolated foragers. However, when nests are broken into, workers may come boiling out and bite the attacker. Very few Neotropical carpenter ants will aggressively defend a nest site. Other species that defend nests include C. sericeiventris, and in South America a close relative of atriceps, C. femoratus.
On multiple occasions I have observed parabiosis between C. atriceps and Azteca. Near the town of Tortuguero, on the Atlantic coast, I found an "archipelago" of antgardens on understory vegetation, overhanging a trail in the forest. The nests I could reach were relatively small and with only a few epiphyte seedlings, and appeared to be satellite or incipient nests at the edge of the large antgarden colony. The Azteca species was one I have not fully identified yet, but it is near ulei and may be gnava. The Azteca were out patrolling the surface of the nests and were very aggressive, but I discovered that the nests also contained C. atriceps. When the small nests were very severely disturbed (broken open with machete or by hand), C. atriceps workers would suddenly emerge. The smaller workers would flee, but major workers attacked me and bit my hands. One of the small nests was adjacent to a cluster of rotten sticks. The sticks were hollow and most contained adult males and alate queens of Azteca. However, one contained an aggregation of C. atriceps workers.
Another case of parabiosis occurred at Santa Rosa National Park. I was night collecting along the nature trail near the Casona. A fissure near the base of a live tree was an active nest entrance where abundant workers of Azteca (instabilis complex) were very active. In amongst them were occasional workers of C. atriceps, moving in and out of the same fissure and traveling among the Azteca workers with no apparent aggression.
A third case occurred near Puerto Viejo de Limon, in beach strand vegetation beneath coconut palms. A small shrub had an external carton nest of Azteca that was very active and vigorously defended. Just beneath and connected to it was a soft rotten stick that contained a C. atriceps nest. The Azteca workers were running freely in and out of the same stick, among the Camponotus workers, with no aggression.
I observed a fourth case at La Selva Biological Station. I discovered a cluster of carton nests of an Azteca velox-like species. The nests were scattered on the leaves and stems of a cluster of small melastome shrubs. One basal, central nest was built around a dead branch, about 50cm long. Camponotus atriceps were parabiotic in the central nest and some of the satellites. The Camponotus maintained galleries apart from the Azteca, but the Camponotus and Azteca chambers were interconnected and the two species appeared to move freely among each other. The carton construction was clearly associated with the Azteca chambers in the central branch, and not with the Camponotus chambers. The Azteca appeared to be the carton makers.
A fifth observation was also at La Selva. During night collecting I observed a fissure in the base of a tree, with carton construction covering part of the fissure. Camponotus and Azteca workers were both abundant and occurred together under the carton. The Azteca were in the velox group.
An open question is whether parabiosis in C. atriceps is a facultative behavior exhibited by a single panmictic population, with non-parabiotic cavity nesting being the more common alternative nesting behavior, or are the different nesting behaviors fixed species-level traits exhibited by distinct but cryptic species? Also, is this propensity for parabiosis in C. atriceps related to the apparently obligatory parabiosis in its relative, C. femoratus? Camponotus femoratus is famous for being a highly aggressive antgarden inhabitant in South America always found living parabiotically with Crematogaster carinata (= parabiotica). Are the parabiotic atriceps somehow an intermediate stage in the development of parabiosis, from which C. femoratus was derived?
Nest foundation appears to be by single claustral queens, because I find isolated dealate queens in cavities in dead wood and under epiphyte mats.
Nests are frequently home to inquiline cockroaches and silverfish.
The species is susceptible to fungal infection; Koos Boomsma collected a dead specimen with a sprouting Cordiceps fungus. The collection was from Panama.
Diagnosis among workers of introduced and commonly intercepted species in the United States. 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 5 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 C. sexguttatus); (2) long erect hairs abundant on head, mesosoma and gaster (versus absent in C. rectangularis and C. variegatus); (3)erect hairs that are fine and flexuous (versus thick and stiff in C. planatus); (4) erect scape hairs longer than scape width (versus shorter in C. planatus); (5) gaster concolorous (versus variegated in C. variegatus).
Found most commonly in these habitats: 32 times found in lowland wet forest, 26 times found in tropical moist forest, 12 times found in Port of entry, 14 times found in 2º wet forest, 13 times found in tropical rainforest, 8 times found in lowland rainforest, 8 times found in 2º lowland rainforest, 8 times found in 2º lowland tropical rainforest, 6 times found in mature wet forest, 7 times found in montane wet forest, ...
Collected most commonly using these methods or in the following microhabitats: 70 times search, 39 times MiniWinkler, 34 times Baiting, 29 times Beating, 27 times Malaise, 10 times flight intercept trap, 6 times fogging, 6 times MaxiWinkler, 2 times Berlese/Winkler, 1 times under logs near camp, 2 times Blacklight, ...
Elevations: collected from 10 - 2160 meters, 480 meters average