Editing Formica (section)

==Nests==
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| footer = ''[[Formica obscuripes|F. obscuripes]]'' mound (left) and a ''Formica'' mound on a rotting stump with worker ants (right)
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Mound-building, forest-dwelling ''Formica'' species groups such as ''[[Formica rufa species group|F. rufa]]'' often have a considerable effect on their environments.  They maintain large populations of aphids on the secretions of which they feed, and which the ants defend from other predators.<ref>{{Cite web|url=https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/animals/bees-wasps-and-ants/southern-wood-ant/|title=habitat}}</ref> They also prey on other insects.  In fact, in many countries, they  are introduced in forests to control tree pests, such as swains jack pine sawfly and eastern tent caterpillars in North America. The effects of mound-building grassland species such as ''[[Formica montana|F. montana]]'' are not well-studied, but their local abundance, conspicuous mound-building, and very frequent association with aphids and membracids point to a comparably important ecological role.{{Citation needed|date=June 2011}}

''Formica'' nests are of many different types from simple shaft-and-chamber excavations in soil with a small crater or turret of soil above to large mounds, under stones or logs, or in stumps.  None is arboreal. The genus is abundant in both the [[Nearctic]] and [[Palearctic]] regions.  Due to their relatively large size and diurnal activity, they are among the more commonly seen ants in northern North America.{{Citation needed|date=June 2011}}  Some species, including ''[[Formica rufa|F. rufa]]'', which is common in [[Southern England]], make large, visible thatch nests of dry plant stems, leaves, or conifer needles, usually based around a rotting stump.

Most ''Formica'' species are [[Gyne|polygynous]] (have multiple queens per colony), and some are [[Polydomy|polydomous]] (have multiple nests belonging to the same colony).<ref>Klotz, 2008: [https://books.google.com/books?id=Q7T4gg6j7xUC&pg=PA33 p. 33]</ref> Queens may be singly or multiply mated, and may or may not be related.  ''[[Formica polyctena]]'' has polygynous colonies.<ref>Helantera, Heikki, and Liselotte Sundström. “Worker Reproduction in ''Formica'' Ants.” ''[[The American Naturalist]]'' , Vol. 170, No. 1 (July 2007).</ref>

Wood ants typically secrete [[formic acid]]; ''[[Formica rufa|F. rufa]]'' can squirt the acid from its acidopore several feet if alarmed, a habit which may have given rise to the archaic term for ant, "pismire", and by analogy its American equivalent "piss-ant". They can be relatively large; ''[[Formica rufa|F. rufa]]'' workers can reach a maximum length  around 10&nbsp;mm. The eastern US species ''[[Formica dolosa|F. dolosa]]'' and the western ''[[Formica ravida|F. ravida]]'' (syn. ''F. haemorrhoidalis'') may be slightly longer.{{Citation needed|date=June 2011}}

[[File:Formica neogagates, alate.jpg|thumb|Alate ''[[Formica neogagates]]'']]