Coptoformica

This genus is not in use as it is currently considered to be a junior synonym of Formica. Seifert (2000) treated this name as a subgenus of Formica. His general account of the European species that can informally be grouped under this name:


 * Formica exsecta
 * Formica mesasiatica
 * Formica fukaii
 * Formica manchu
 * Formica fennica
 * Formica bruni
 * Formica pressilabris
 * Formica foreli
 * Formica pisarskii
 * Formica forsslundi
 * Formica suecica

The Palaearctic subgenus Coptoformica Mueller, 1923 belongs to the ant genus Formica and is most probably monophyletic. All Coptoformica species constantly share the following character combination:

a) occipital margin of head both in big and small specimens deeply excavated; depth of excavation 4.9-9.6% of overall head width (CW);

b) mandibles always with one to three prebasal denticles, i.e. denticles positioned caudolateral of the true masticatory border;

c) dorsal crest of the petiolar scale always excavated; depth of excavation usually 3-10% of maximum scale width. Petiole scale thin in lateral view;

d) isometry of index SL/CW (see section 4).

This character combination is not found in any other species of the tribe Formicini. The genus Rossomyrmex shows character (a) but has a very thick, petiole scale and no prebasal mandibular denticles. Members of the Nearctic Formica exsectoides group occasionally show prebasal denticles, but have a weakly or not excavated occiput (0-3.5% of CW), differ in petiolar shape, and show a negative allometry of SL against CW. The monophyly of Coptoformica was also suggested by Agosti (1989). An elevation to genus rank seems acceptable but is not performed here in the absence of a profound phylogenetic study of all species groups presently combined in the genus Formica Linnaeus, 1758.

A unique biological trait not found in other members of the tribes Formicini and Lasiini is shared by obviously all Coptoformica species; it is the mode of constructing the hull of the vegetable nest dome with finely cut pieces of herbs (preferentially grasses). This peculiar behaviour is also observed in Formica suecica, although this species rarely uses this technology. The effective cutting of grasses and the painfull biting of Coptoformica ants that is known to every investigator can be explained by an altered mechanical system of mandible and adductor muscle which is considered as autapomorphy (Dietrich 1998).

Dietrich compared mechanical parameters of the mandible adductor system in Coptoformica exsecta and Formica pratensis. An elongated lever between the mandibular condyles and the attachment point of adductor muscle in combination with a shortened lever between the mandibular condyles and the effective biting point leads to a significantly increased biting power in Coptoformica. Such a system, however, needs longer adductor contraction distances. The necessary elongation of the whole muscle has led to a posterior extension of occipital corners in Coptoformica. This autapomorphy could be a special adaption to nest construction and enables the very effective decapitation of enemy ants and powerful disintegration of food items as e.g., large Lumbricidae.

All queens of Coptoformica cannot found new nests independently in a claustral or semiclaustral way. The initial step of colonizing a new site is single queen (flight) dispersal with subsequent socially parasitic colony foundation in host species of the subgenus Serviformica Forel, 1913. Except for Formica (Coptoformica) forsslundi that seems to have Formica (Serviformica) transkaucasica as exclusive host in all parts of its geographic range, distributional data demand that most Coptoformica species are not strictly host specific. There are observations suggesting how single queens of either Formica (Coptoformica) pressilabris or Formica foreli (species identity unclear) can found new colonies (Kutter 1969). They go to a nest entrance of a Serviformica species, adopt a nymphal posture, and are carried by a host worker into the nest without being attacked or mutilated.

Nomenclature

 * COPTOFORMICA [junior synonym of Formica]
 * Coptoformica Müller, 1923: 146 [as subgenus of Formica]. Type-species: Formica exsecta, by subsequent designation of Donisthorpe, 1941f: 37.
 * Coptoformica senior synonym of Adformica: Stitz, 1939: 306 (as Adformica and Coptoformica share the same type-species synonymy is absolute).
 * Coptoformica junior synonym of Formica: Smith, M.R. 1951a: 860; Smith, D.R. 1979: 1448; Agosti, 1994a: 107.