Formica sanguinea Latreille

56. Formica sanguinea Latreille, 1798 Figs. 221-223.

Formica sanguinea Latreille, 1798: 37.

Worker. Alitrunk and front of head bright red; gaster and ocellar region of head brownish black. Proportion of dark to red varies from north to south with some arctic samples having preponderantly dark heads and dusky red alitrunk contrasting with southern samples which may have whole body excluding gaster bright red. Frontal triangle dull; eyes without hairs. Clypeus with median anterior notch variable in size and shape but always present. Head and mandibles broad relative to alitrunk and gaster. Length: 6.0-9.0 mm.

Queen. As worker with dark areas on alitrunk absent or restricted to sides of mesopleurae, but some northern samples darker. Gaster small in relation to head. Length: 9.0-11.0 mm.

Male. Black, legs yellow. Clypeal notch less distinct than in female castes. Mandibles each with four or five small teeth. Frontal triangle dull; eyes bare. Length: 7.0-10.0 mm.

Distribution. Common throughout Denmark and Fennoscandia. - Locally common in England and Scotland. - Range: throughout Eurasia from Portugal to Japan and Iran to Arctic Norway.

Biology. This is the well known aggressive red slave-making ant raiding nests of any species in its neighbourhood during the summer and removing pupae of the Formica fusca group of species for rearing in the parent nest as auxiliaries and also as food. All Fennoscandian species of the F. fusca group have been found in mixed colonies with F. sanguinea including F. rufibarbis. F. cinerea. F. gagatoides and F. transkaucasica as well as the more frequent F. fusca or F. lemani. F. sanguinea tends to avoid in-fighting but overwhelms other species by abrupt aggressive movements. Nests are situated under stones or in tree stumps with a small accumulation of leaf litter. It is often a dominant species in cleared woodland and in some localities all other Formica species have been eliminated and in such cases only pure F. sanguinea colonies are to be found, usually with a high proportion of small workers to act as nurses. Colonies spread by nest splitting and also by individual queens entering nests of the auxiliary species and appropriating a part of the brood, the host queen or queens being subsequently destroyed. Alatae are developed in July pairing often occurring in the vicinity of the nest.