Camponotus

Wheeler, W. M., 1922, The ants collected by the American Museum Congo Expedition., Bulletin of the American Museum of Natural History 45, pp. 39-269 : 232-234

Camponotus Mayr

Worker medium-sized to very large, potymorphic, rarely dimorphic, the worker maxima having a large, broad head, the minima a much smaller head and more slender body, the media being intermediate in structure. Head differing considerably in form in different species, usually broad and more or less excised behind, narrower in front, very convex above and flattened beneath. Mandibles powerful, short, triangular, with coarse teeth on their broad apical borders; external border and upper surface convex in large individuals. Palpi moderately long, the maxillary pair 6-, the labial pair 4-jointed. Clypeus large, trapezoidal or subrectangular, usually carinate or subcarinate, often divided into a large, median, subhexagonal and two small, triangular, lateral divisions, which do not reach the lateral border of the cheeks, the anterior border entire or emarginate, often excised on each side, with a broad, more or less projecting median lobe. Frontal area small, triangular or lozenge-shaped; frontal groove distinct; frontal carinae long, prominent, marginate, and sinuate or S-shaped, rising from the posterior border of the clypeus. Eyes moderately large, broadly elliptical, not very prominent, situated behind the middle of the head; ocelli absent, the anterior ocellus sometimes indicated. Antennae 12-jointed; scapes sometimes thickened distally, inserted some distance behind the posterior border of the clypeus; funiculi long, filiform, not enlarged at their tips, all the joints longer than broad. Thorax differing greatly in shape in the various species, typically broadly and more or less evenly arcuate in profile, broad in front, laterally compressed behind, the epinotum usually simple and unarmed. Rarely the mesonotum is impressed or sellate. Petiole surmounted by an erect scale, the upper border of which may be blunt or anteroposteriorly compressed, entire, subacuminate or more or less emarginate. Gaster rather large, broadly elliptical, its first segment forming less than half its surface. Legs long and well developed. Gizzard with a long slender calyx, the sepals of which are not reflected at their anterior ends.

Female larger than the worker maxima but usually with smaller head. The latter and the petiole much as in the worker. Ocelli present. Thorax elongate elliptical; pronotum short, its posterior margin arched, its posterior angles reaching back to the insertions of the wings, mesonotum and scutellum long, convex; metanotum depressed below the scutellum. Gaster elongate elliptical, massive. Wings long and ample, the anterior pair with a radial, one cubital, and no discoidal cell.

Male small and slender; head small, with very prominent eyes and ocelli. Mandibles small and narrow. Antennae 13-jointed, slender, scapes long. Petiolar node thick and blunt; gaster elongate, with small slender genital appendages. Legs very slender. Wing venation as in the female.

Pupae nearly always enclosed in cocoons.

This huge cosmopolitan genus, comprising more than 1000 described forms, has become so unmanageable that Forel and Emery have recently split it up into some thirty-six subgenera. The frequent occurrence of species of Camponotus in all countries, except Great Britain and New Zealand, and the extraordinary variability of many of the species in response to slight differences of environment make the genus one of considerable interest to the student of geographical distribution. In the Ethiopian Region, it is represented by numerous species assignable to no less than eleven of the thirty-six subgenera recognized by Emery and myself, namely, Myrmoturba , Dinomyrmex (Map 41), Myrmosericus , Myrmothrix (one species, probably introduced). Orthonotomyrmex , Myrmotrema (Map 38), Myrmopiromis , Myrmorhachis , Myrmopsamma , Myrmamblys , and Colobopsis , and species of six others, Camponotus , sensu stricto, Myrmosaulus , Myrmosaga , Mayria , Myrmonesites , and Myrmopytia , occur in f lie Malagasy Region. A few of these subgenera, Myrmopsamma and Myrmopiromis , are peculiarly African, while others, Myrmosaga , Mayria , Myrmonesites , and Myrmopytia , are only found in Madagascar. The development of the subgenus Myrmoturba and especially of the species maculatus (Fabricius) , the typical form of which is West African, is extraordinary, as will be seen by consulting the catalogue(Part VIII). C. (Myrmoturba) maculatus (Map 39) and two other species, C. (Myrmosericus) rufoglaucus (Map 42) and C. (Orthonotomyrmex) sericeus (Map 43), have a singular distribution. Forms of maculatus occur in all the continents; rufoglaucus , with many varieties, ranges from southern China across India and equatorial and South Africa to the Gulf of Guinea; and sericeus occupies a similar range, though showing little tendency to produce subspecies and varieties.

The species of Camponotus often form very populous colonies and exhibit a great diversity of nesting habits. Many live in the ground, either under stones or in crater nests, others under bark, in dead wood, hollow twigs, and galls, and a few construct carton nests or employ their larvae, after the manner of Oecophylla , in spinning together particles of vegetable detritus with silk ( C. senex and formiciformis ). The food ofthe various species consists of miscellaneous insects, the excreta of aphids (honeydew), and nectar. Many of the smaller forms are stolid, apathetic, or timid, but the maxima workers of the large species belonging to the subgenera Dinomyrmex , Myrmoturba , Myrmothrix , and Myrmopiromis are very pugnacious and capable of inflicting painful wounds with their powerful mandibles.