Formica

For the plastic, see Formica (plastic).
Formica
Formica rufa
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Formicini
Genus: Formica
Linnaeus, 1758
Type species
Formica rufa[1]
Diversity[2]
234 species
Synonyms

Adformica Lomnicki, 1925
Coptoformica Müller, 1923
Formicina Shuckard, 1840
Neoformica Wheeler, 1913
Raptiformica Forel, 1913
Serviformica Forel, 1913

Formica is a genus of ants of the family Formicidae, commonly known as wood ants, mound ants, thatching ants, and field ants. Formica is the type genus of the Formicidae, and of the subfamily Formicinae.[3] The type species of genus Formica is the European red wood ant Formica rufa.[1] Ants of the genus formica tend to be between 4 to 8mm long.[4]

Habitat

As the name wood ant implies, many Formica species live in wooded areas where there exists no shortage of material with which they can thatch their mounds. One shade-tolerant species is F. lugubris. However, sunlight is important to most Formica species, and colonies rarely survive for any considerable period in deeply shaded, dense woodland. The majority of species, especially outside the rufa species group, are inhabitants of more open woodlands or treeless grassland or shrubland. In North America, at least, these habitats had a long history of frequent landscape-scale fires that kept them open before European settlement. Conversion to agriculture and fire suppression have reduced the abundance of most American Formica, while the cessation of traditional haycutting seems to have had the same effect in Europe. However, at least a few Formica species may be found in a wide range of habitats from cities to seasides to grasslands to swamps to forests of the temperate Northern Hemisphere.

In more suburban landscapes, they tend to nest near structures like sidewalks, fences, or building foundations.[4]

Nests

F. obscuripes mound (left) and a Formica mound on a rotting stump with worker ants (right)

Mound building, forest dwelling Formica such as F. rufa often have a considerable effect on their environment. They maintain large populations of aphids on whose secretions they feed, and which the ants defend from other predators. 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 F. montana are not well-studied but their local abundance, conspicuous mound-building and very frequent association with aphids and membracids points to a comparably important ecological role.

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 are 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. Some species, including 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 polygynous (having multiple queens per colony), and some are polydomous (having multiple nests belonging to the same colony).[5] Queens may be singly or multiply mated, and may or may not be related. Formica polyctena is one species that has polygynous colonies.[6]

Wood ants typically secrete formic acid; Formica 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: F. rufa workers can reach a maximum length of around 10 mm. The eastern US species F. dolosa and the western F. ravida (syn. F. haemorrhoidalis) may be slightly longer.

Social Characteristics

Ants are eusocial organisms meaning that the individuals of the species work together in order to survive and to produce the next generation. Ants work together in order to accomplish tasks which cannot be accomplished alone.[7] Unlike other some ants, the genus Formica does not have separate castes, which are based on an individuals specialization and morphology. For example, Formica selysi, a species native to floodplains, have developed a method to deal with flooding. Individual ants come together to form a living raft in order to survive the flood. Recent studies have shown that individual ants tend to take the position in the raft which they were in the past. This return to the same role in the raft is an example of specialization.[7]

"Slave-making" behavior

Formica are notable for their parasitic and slave making behaviors. There are three categories:

Some species of this group need to do this to survive, for others it is optional.

Species

Formica accreta worker, with cocoons
Formica integroides worker

As of 2016, Formica contains 175 extant species and 59 extinct species.[2]

Species include:[9]

References

Notes

  1. 1 2 "Genus: Formica". antweb.org. AntWeb. Retrieved 23 September 2013.
  2. 1 2 Bolton, B. (2016). "Formica". AntCat. Retrieved 25 April 2016.
  3. "Family: Formicidae". antweb.org. AntWeb. Retrieved 2 October 2013.
  4. 1 2 "Feild Ant Facts". Orkin. Retrieved 2016-03-31.
  5. Klotz, 2008: p. 33
  6. Helantera, Heikki, and Liselotte Sundström. “Worker Reproduction in Formica Ants.” The American Naturalist , Vol. 170, No. 1 (July 2007).
  7. 1 2 Avril, Amaury; Purcell, Jessica; Chapuisat, Michel (2016-04-07). "Ant workers exhibit specialization and memory during raft formation". The Science of Nature 103 (5-6): 1–6. doi:10.1007/s00114-016-1360-5. ISSN 0028-1042.
  8. cf. P. Huber via Darwin's Origin of Species, in Chapter VIII. Instinct
  9. Formica species list. Integrated Taxonomic Information System (ITIS).

Bibliography

External links

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