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fusca group

Black ants of some sort. - Formica subaenescens Black ants of some sort. - Formica subaenescens Formicidae - Formica neoclara Ants, 5100 feet on Mt. Washington - Formica neorufibarbis Formica subsericea worker - Formica podzolica Formica argentea - female Formica subsericea Queen - Formica subsericea - female
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Hymenoptera (Ants, Bees, Wasps and Sawflies)
No Taxon (Aculeata - Ants, Bees and Stinging Wasps)
Superfamily Formicoidea (Ants)
Family Formicidae (Ants)
Subfamily Formicinae
Tribe Formicini
Genus Formica (Wood ants, mound ants, & field ants)
No Taxon fusca group
Classical pronunciation was approximately "for-MEE-kah FOOS-kah", but most English speakers say "for-MY-kuh (or FOR-mick-uh) fusk-uh"
Synonyms and other taxonomic changes
In Europe, this group is referred to as the subgenus Serviformica, in reference to their commonly being found as the host in nests of "slavemaker" ants. American myrmecologists don't use this name for various reasons, not the least being that it is not monophyletic.
Explanation of Names
Formica - Latin for ant
fusca - Latin for dark, dusky, blackish
workers 4.5-7mm
Uniformly dark dark gray, blackish or dark brown Formica, or with some dark yellowish or brown patches around the mouthparts, on the mesosoma. Legs often deep red or brown. (F. neoclara exceptional in being uniform light yellowish brown in some populations; it is neither sympatric with nor as shiny as other yellowish NA species.)
Holarctic. In North America, this group is most diverse in western mountain ranges (even south into Mexico and Guatemala at high altitude), with partially distinctive Pacific and Rocky Mountain species composition. It is rather less diverse across Canada and northern US states. A single, but very common species, F. subsericea, occurs in unglaciated portions of the eastern US.
Grasslands and open woodlands, a few also occurring in bogs or fens or deeply shaded forests.
Spring till autumn; often relatively inactive in late summer, becoming active again in early fall.
Actively gather honeydew from source insects, and extrafloral nectar. Prey on insects and spiders. Also scavenge small dead invertebrates, honeydew on leaf litter and plant surfaces, etc.
Life Cycle
Colonies enter winter without brood, as egg production ceases in late July or August. The spring brood gives rise to a mix of workers and (in mature colonies) to sexual forms. The latter fly mainly in July, with lesser numbers in adjacent months. Typically, only (or mostly) workers are reared through the rest of the season.
Queens rear their first brood alone, sealed into a small nest cell of their own making. Colonies mature (i.e., raise the first winged sexuals, often only males in earlier years) in the third season after founding. Colonies persist 10 or more years.
Print References
Francoeur, A. Révision taxonomique des espèces néarctiques du groupe fusca, genre Formica. Mémoires de la société entomologique du Québec 3.
(Keys to workers, and winged males and females in English included. PDF here. 23.9 MB)

Wheeler, G. and J. 1986 Ants of Nevada. Natural History Museum of Los Angeles Co.