Formica lugubris

This ant was found by Boulay et al. (2007) to be one of two important ant dispersers (also Camponotus cruentatus) of myrmecochorous seeds of the plant Helleborus feotidus. F. lugubris was responsible for 67% of the observed visits and 80% of the observed seed removals from a population from northwestern Spain.

Identification
A sibling species of Formica paralugubris, these two species can be separated using queen pilosity characters and morphometrics (tables and discriminant functions to separate these two species and Formica aquilonia are provided by Seifert 1996).

Collingwood (1979) - Bicoloured with distinct but not well demarcated dark patch on promesonotum. Frontal groove distinctly shining. Large punctures coarse and deep, widely dispersed among close set microscopic puncturation. Occiput with a thick fringe of hairs extending forward over area between ocelli and sides of head and laterally round to the eyes. Eye hairs erect and prominent. Body pilosity including gula, tibiae and femora more or less densely pilose. Some populations have scape hairs. Head width of largest workers 2.1 mm. Length: 4.5-9.0 mm.

Distribution
Northern Eurosiberia and European mountains from Pyrenees to Kamchatka and Japan, Italy to North Norway (Collingwood 1979).

Distribution based on Regional Taxon Lists
Palaearctic Region: Albania, Andorra, Austria, Belarus, Bulgaria, China, Croatia, Czech Republic, Democratic Peoples Republic of Korea, Estonia, Finland, France, Germany, Greece, Iberian Peninsula, Ireland, Italy, Latvia, Mongolia, Montenegro, Norway, Poland, Republic of Korea, Romania, Russian Federation, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, Ukraine, United Kingdom of Great Britain and Northern Ireland.

Biology
Collingwood (1979) - This is a robust active species. Colonies are often in groups with inter-connecting nests. It has similar habits to Formica rufa but is able to forage at much lower temperatures and replaces F. rufa entirely from Central Fennoscandia to the far north. This species varies in the presence, abundance or absence of scape hairs in the female castes and some local populations in South Finland and in the Alps with such hairs have widely spaced micropunctures on the dorsum of the gaster as in F. rufa. Because of great variability among local populations in these areas it has not been possible to demarcate the extreme forms as a separate species but samples mainly from coastal areas and offshore islands in Nylandia include some extremely hairy specimens with queens consistently having wide spaced micropunctures which are well outside the range of F. lugubris as described by Yarrow (1955) and Betrem (1960). Bondroit (1917) briefly described a form, F. rufa var. nylanderi, as having long outstanding body and antennal hairs and F. nylanderi could be a suitable name for this form, if distinguished as a species.

F. lugubris spreads by colony fission but also by the adoption of fertile queens by Formica lemani. Such mixed incipient nests often under stones have frequently been seen in Norway and North Sweden (Collingwood, 1959).

Foraging/Diet
Formica lugubris collect large quantities of honeydew.

Novgorodova (2015b) investigated ant-aphid interactions of a dozen honeydew collecting ant species in Western Siberia pine and aspen-birch-pine forests (54°7´N, 83°06´E, 200 m, Novosibirsk) and mixed-grass-cereal steppes with aspen-birch groves (53°44´N, 78°02´E, 110 m, near Karasuk) in the Novosibirsk Region and coniferous forests in the northeastern Altai (north end of Lake Teletskoe, 51°48´N, 87°17´E, 434 m). All of the ants studied had workers that showed high fidelity to attending particular aphid colonies, i.e, individual ants tend to return to the same location, and group of aphids, every time they leave the nest. F. lugubris' honeydew collecting activities were highly coordinated during the summer months when the aphids and ants were most active. Individual foragers specialized on specific tasks and could be classified as shepherds (collect honeydew), guards (protect aphids from competitors), scouts (search for new aphid colonies) and transporters (transport honeydew to the nest). Individuals performed the same type of work day after day, with groups of the same workers, thereby forming teams. F. lugubris tended: Symydobius oblongus (Heyden) and Cinara laricis (Hartig).

Nesting Biology
This species is polydomous and is considered to be a member of a Formica species group known as wood ants. Ellis and Robinson (2015) conducted a 3 year field-study of a population (2012-2014, Peak District, England) of Formica lugubris to ascertain the potential benefit of non-foraging nests. Abstract - A colony of red wood ants can inhabit more than one spatially separated nest, in a strategy called polydomy. Some nests within these polydomous colonies have no foraging trails to aphid colonies in the canopy. In this study we identify and investigate the possible roles of non-foraging nests in polydomous colonies of the wood ant Formica lugubris. To investigate the role of non-foraging nests we: (i) monitored colonies for three years; (ii) observed the resources being transported between non-foraging nests and the rest of the colony; (iii) measured the amount of extra-nest activity around non-foraging and foraging nests. We used these datasets to investigate the extent to which non-foraging nests within polydomous colonies are acting as: part of the colony expansion process; hunting and scavenging specialists; brood-development specialists; seasonal foragers; or a selfish strategy exploiting the foraging effort of the rest of the colony. We found that, rather than having a specialised role, non-foraging nests are part of the process of colony expansion. Polydomous colonies expand by founding new nests in the area surrounding the existing nests. Nests founded near food begin foraging and become part of the colony; other nests are not founded near food sources and do not initially forage. Some of these non-foraging nests eventually begin foraging; others do not and are abandoned. This is a method of colony growth not available to colonies inhabiting a single nest, and may be an important advantage of the polydomous nesting strategy, allowing the colony to expand into profitable areas.

Nomenclature

 *  lugubris. Formica lugubris Zetterstedt, 1838: 449 (m.) NORWAY. Junior synonym of rufa: Nylander, 1856b: 60; Emery & Forel, 1879: 450; Wheeler, W.M. 1913f: 425; Emery, 1925b: 253; Stitz, 1939: 328. Revived from synonymy and status as species: Yarrow, 1955a: 5; Betrem, 1960b: 77; Dlussky, 1967a: 91; Dlussky & Pisarski, 1971: 180; Baroni Urbani, 1971c: 218; Kutter, 1977c: 271; Gösswald, 1989: 19; Kupyanskaya, 1990: 198; Atanassov & Dlussky, 1992: 274. Senior synonym of congerens: Yarrow, 1955a: 5; Dlussky, 1967a: 91; Radchenko, 2007: 36; of nylanderi, santschii: Yarrow, 1955a: 5; of montana Sadil: Samsinak, 1964: 157; of unicolor: Dlussky, 1967a: 91; Dlussky & Pisarski, 1971: 180. Material of the unavailable name tir referred here by Yarrow, 1955a: 5.
 * congerens. Formica congerens Nylander, 1846a: 906 (w.) FINLAND. Nylander, 1849: 30 (m.); Foerster, 1850a: 17 (q.). Junior synonym of pratensis: Emery & Forel, 1879: 450; Nasonov, 1889: 17; Wheeler, W.M. 1913f: 428; Forel, 1915d: 57; Emery, 1916b: 256; Müller, 1923: 142. Revived from synonymy: Betrem, 1953: 324. Junior synonym of lugubris: Yarrow, 1955a: 5; Dlussky, 1967a: 91; Radchenko, 2007: 36.
 * alpina. Formica rufa var. alpina Santschi, 1911j: 349 (w.) ITALY. [Junior primary homonym of alpina Wheeler, above.] Replacement name: santschii Wheeler, 1913f: 428. Raised to species: Bondroit, 1918: 59.
 * santschii. Formica rufa var. santschii Wheeler, W.M. 1913f: 390 (in key). Replacement name for alpina Santschi, 1911j: 349. [Junior primary homonym of alpina Wheeler, W.M. 1909e: 85.] Junior synonym of lugubris: Yarrow, 1955a: 5.
 * nylanderi. Formica rufa var. nylanderi Bondroit, 1920a: 145 (q.) FRANCE. [Also described as new by Bondroit, 1920b: 300.] Junior synonym of lugubris: Yarrow, 1955a: 5; Seifert, 1996: 200.
 * unicolor. Formica pratensis subsp. unicolor Ruzsky, 1926: 110 (w.) RUSSIA. [First available use of Formica rufa subsp. pratensis var. unicolor Ruzsky, 1914b: 102; unavailable name.] Junior synonym of lugubris: Dlussky, 1967a: 91.
 * montana. Formica rufa var. montana Sadil, 1953b: 198, fig. 1 (q.) CZECHOSLOVAKIA. [Unresolved junior primary homonym of montana Wheeler, W.M., above.] Junior synonym of lugubris: Samsinak, 1964: 157.