Formica exsecta

AntWiki - Where Ant Biologists Share Their Knowledge
Jump to: navigation, search
Formica exsecta
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Formicini
Genus: Formica
Species: F. exsecta
Binomial name
Formica exsecta
Nylander, 1846

Formica exsecta casent0173161 profile 1.jpg

Formica exsecta casent0173161 dorsal 1.jpg

Specimen labels

Synonyms

This is an active aggressive species building mounds of leaf litter in open woodland, moorland and rough pasture. On disturbance the ants swarm out and bite vigorously. Nests may contain a thousand or more workers. F. exsecta is mainly aphidicolous tending aphids on Juniperus, Picea and other trees but is also predaceous. Colonies extend by nest splitting but single queens also start colonies by securing acceptance in nests of Formica lemani or Formica fusca. Alates occur in July (Collingwood 1979).

At a Glance • Temporary parasite  • Supercolonies  • Polygynous  
 

Identification

Bicoloured with gaster dark brown, rest of body reddish with varying amount of dark colour on head and promesonotum. Head strongly excised posteriorly; maxillary palps 6 segmented, long as half head length. Scale strongly emarginate. Eyes with very distinct erect hairs which are normally abundant. Body pilosity variable - erect hairs on all gaster tergites, on clypeus and on dorsum of head, sometimes also on occipital margins. Clypeus not impressed. Length: 4.5-7.5 mm (Collingwood 1979).

Seifert (2000) - Interspecific setae and pubescence differences between Coptoformica species are normally correlated with differences in body measures and indices at least in the queens. Investigations of the enormous setal and pubescence variability of the exsecta samples seen during this study could not convincingly show such correlations and could not satisfactorily separate entities of possible taxonomic significance. The same local population may show a wide range of pubescence and pilosity variance and there is no clear indication that certain setae morphs could be associated with a certain distribution, habitat selection, or biology. As a consequence and in agreement with the view of Agosti (1989), Formica exsecta is considered here as polymorphic, relatively eurytopic species with a large range, similar to the situation in Formica truncorum, Formica pratensis, and Scandinavian Formica lugubris. This conception of F. exsecta contrasts the situation in the other Coptoformica species that are constant, monomorphic entities with a defined zoogeography and more specific habitat selection. Males: Eyes with numerous long hairs; EyeHL 35-50 μm. Clypeus with numerous setae; ClySet 2-5. Mesosoma with numerous standing setae. Craniad profile of forecoxae with standing setae.

Keys including this Species

Distribution

Seifert (2000) - South to Central Spain, to the N Appennine and to the Balkans at 40°N. Found in high Anatolia and Caucasus; apparently absent from the driest Pontic and Caspian steppe zones. West to SW England and the Scottish Highlands. Northern range troughout Fennoscandia up to North Cape. Distribution in the east in European Russia, across Siberia, Mongolia, NE China (Beishan National Park, 37°N, 102°E) and east to the lower Amur river. The northern distribution in the continental parts of Eurasia is limited by the -8 °C isotherm of soil in a depth of one meter (achieved at 67°N in W Siberia at the Ob river and at 62°N in E Siberia at the Lena river) and the southern distribution coincides with the southern border of foreststeppe (Dlussky 1967). Vertical distribution: in Switzerland and Austria 300-2250 m, bimodal, with very low frequencies from 800-1200 m; Bulgarian mountains 1100-2200 m.

Distribution based on Regional Taxon Lists

Palaearctic Region: Albania, Andorra, Armenia, Austria, Belarus, Belgium, Bulgaria, China, Czech Republic, Denmark, Estonia, Finland (type locality), France, Germany, Greece, Hungary, Iberian Peninsula, Italy, Kazakhstan, Kyrgyzstan, Latvia, Liechtenstein, Lithuania, Luxembourg, Mongolia, Netherlands, Norway, Poland, Republic of Macedonia, Republic of Moldova, Romania, Russian Federation, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, Ukraine, United Kingdom of Great Britain and Northern Ireland.

Distribution based on specimens

Loading map...

The above specimen data are provided by AntWeb. Please see Formica exsecta for further details

Habitat

Seifert (2000) - F. exsecta is more a generalist with a wider habitat selection than usual within Coptoformica species. Very different open or slightly shaded habitats, which must have medium-term stability at least, are inhabited. A high cover percentage of grasses within the field layer is typical but not essential. As for all species of the group, sites with rapid plant succession, with high nitrogen input, or sites within the inundation plains of rivers are not colonised. Formica exsecta and all other members of the group cannot increase nest temperatures by metabolic heat production independent of environmental temperatures as known for populous nests of some wood ant species. The dependence of Coptoformica upon direct insolation is thus increased and nests cannot be constructed in fully shaded woodland habitats. Habitat types used by exsecta are subalpine and boreomontane pastures, clearings and margins of woodland, sunny forests, semidry to xerothermous grasslands, heathland, and dryer spots of bogs and fens.

Biology

Goryunov (2015) - Narrow-headed ants mostly inhabit rapidly changing ecotone biotopes. In addition, F. exsecta is obligatorily dominant in multispecies ant assemblages and has to maintain this position from the very foundation of the colony. Thus, this model species has to possess adaptations that would allow it to promptly respond to changes in the environment. Some of these adaptations are realized in its nest-building activity. Simple and movable auxiliary nests facilitate rapid colonization of new areas or help to change the population density in the existing colonies. By relocating auxiliary nests across the foraging area, F. exsecta ants can quickly install supporting points for foragers at the sites rich in food. After the sites are no longer important, ants can take the building material back to the primary nest and do not have to collect the material anew when it is needed. The absence of the inner cone and the propensity for relocation of material allow mature F. exsecta anthills to move together with the forest edge. In addition, building material exchange among formicaries can contribute to integration of different families within the colony, which, in turn, helps to consolidate large complexes with high nesting density.

Seifert (2000):

Status as threatened species

Red List Germany: three (threatened). In Central Europe it is probably the least endangered Coptoformica species though its populations have significantly declined since 1950. The decline is caused by afforestation of clearings and meadows, vanishing of coppice wood management, decline of sheep pasturing, intensifying of cattle pasturing, intensive use of mineral fertilisers and liquid manure, and high athmospheric nitrogen immission. Dewes (1993) recorded F. exsecta colonies in the Nature Park Saar-Hunsrück preferentially in sites of historic coppice wood management where oak bark for tanneries was harvested.

Colony foundation

Flight or ground dispersal of single queens is followed by socially parasitic colony foundation in nests of the subgenus Serviformica. Formica fusca (Dlussky, Collingwood, Pisarski, Agosti, Seifert) and Formica lemani (Collingwood, Agosti, Hellrigl, Seifert) are reported as host species. According to Pisarski (1982), socially parasitic colony foundation is only possible in queenless host nests. The same author stated that monogynous nests of exsecta never accept alien queens, with exception of very minute nests. To become polygynous, they must have lost the queen and can then adopt several queens simultaneously. Once shifted to polygyny, huge polycalic colony systems may develop by nest splitting.

Development and microclimatic requirements

Alates develop from eggs laid in early spring. Oviposition starts in Central European lowland habitats in late March but is considerably delayed with growing altitude and latitude. In Finnish monogynous colonies, less than 5% of the spring eggs develop to workers (Chapuisat et al. 1997), but this ratio may reach 50% in Swiss polygynous societies (Schneider pers. comm.). The main source of worker production is late spring or summer eggs. The optimum temperature for “brood development” is 28-30 °C (Grinfeld 1939, cited in Dlussky 1967). The supercooling point of winter-adapted Siberian workers is -20 °C; the long-term minimum at which 50% of workers survive is -8 °C (Berman, Shigulskaja & Leirich 1987; Leirich 1989). The conditions where soil temperatures in a depth of one metre do not decline below -8 °C are given in E Siberia up to 62°N, which coincides with the northern distributional border of exsecta.

Demography of nests and colonies

The ratio of monogynous nests vs polygynous/polycalic colonies differs locally and geographically. Patchiness and general availability of suitable habitats and a payoff between the costs of single queen colony foundation and the costs of reproductive competition in polygynous nests are probable factors influencing this ratio. In S Finland monogyny/monodomy clearly predominates. Big polycalic colonies are known from the Alps, Central Europe, and European Russia. The mean longevity of queens in monogynous nests in S Finland was over 20 years (Pamilo 1991). According to Sundström et al. (1996), 39% of the queens in 57 monogynous S Finnish nests were multiply-mated (polyandrous). The sex ratio of produced alates is strongly dependent upon the number of queens in a colony and the number of mates per queen; in highly polycalic colonies in the Swiss Alps it was about 15:1 (Schneider pers comm.), in Finnish polyandrous/monogynous colonies it was 3.76:1, but in Finnish monoandrous/monogynous nests it was 1 : 2.2. Workers of the latter colonies increased their inclusive fitness by selectively killing male larvae before pupation and (most probably) feeding them to the now rapidly growing female larvae. Ecological and demographic factors (recource limitation!) are believed to interfere with genetic factors (optimisation of kinship value), i.e. males should survive in higher numbers in monoandrous/monogynous nests if there is plenty of recources (Chapuisat et al. 1997). Monogynous nests mainly produce the large male morph (macraner) but polycalic colonies mainly micraners (Pamilo & Rosengren 1984). The micraners can develop from worker-laid eggs, mature later, and show narrower activity peaks. Both micraners and macraners are normally haploid (Agosti 1989). No complete population census has been performed so far in exsecta. The “Aussendienst” population of four monogynous nests of 368 ± 100 cm2 basal area was censused by Pisarski (1982) as 2750 ± 1000 workers, i.e. 7.5 workers/cm2 basal nest area. That means a total population of 18.8 workers/cm2 basal nest area if assuming 40% Aussendienst workers. The total population of exactly censused polygynous bruni nests was 39.3 workers/cm2 basal nest area (Schneider pers. comm.). Both values seem realistic in view of the higher worker density and smaller worker size in polygynous nests. A very large polygynous exsecta nest of 150 cm diameter should then contain > 300 000 workers. Polycalic exsecta colonies may be huge and can dominate a site as known for Formica polyctena. Dewes (1993) described a supercolony comprising 408 nests (the smallest not counted!) spreading over an area of 2 ha. If assuming only 25 000 workers for an average polygynous exsecta nest, the whole population of this colony should be > 10,000,000.

Swarming

Mature alates are found in the nest 28.2 July ± 20.2 d (10 June-4 Sept, n = 33). In contrast to R. Rosengren, M. A. Schneider did not observe micraners to fly higher and farther than macraners. In Swiss polycalic colonies about 30% of females fly, the others are inseminated at the nest mounds. Swarming is restricted to the the first half of the day (between 5.30 and 12.20 h) and starts as soon as the first direct sunlight hits the mound surface. Completely cloudy sky or strong air movement prevents the flight and beginning sunshine in the second half of the day can not release it (Schneider pers. comm., and my own observations).

Food sources

F. exsecta can use a wide range of food sources. Trophobiosis with epigaeic and subterranean Aphidina (and more rarely Cicadina and Coccina) is observed and obviously covers a major portion of the energy needs. Lachnidae are the main trophobionts in coniferous and deciduous forests. Zoophagy may be important and is then comparable to that of Formica polyctena with the difference of a smaller average size of prey items (Wesselinov & Horstmann 1968); all kinds of dead or living Arthropoda and Lumbricidae are consumed. Very populous supercolonies effectively displace different species of predatory arthropods from their territory.

Intraspecific behaviour

Monogynous colonies are highly aggressive against conspecific aliens. Polygynous/monodomous colonies show reduced aggressivity but only polycalic colonies do not establish territorial boundaries against other conspecific polycalic colonies (Pisarski 1982).

Nesting Biology

Goryunov (2015) - Red wood ants and closely related species build intricate composite aboveground nests with a subterranean part (Dlussky, 1967). The subterranean part is organized similarly to nests located completely underground. The aboveground part is represented by the mound which consists of two elements. Within the mound, there is an inner cone built of relatively large pieces of branches. The inner cone is the backbone of the structure, and this is also where most chambers are situated. It is overlain with a coating cover built of relatively fine plant fragments such as needles, leaves, thin twigs, etc. The mound is elevated on an earthen bank which is built of soil evacuated during the construction of the subterranean part of the nest.

Formica exsecta also build nests with aboveground mounds that include plant fragments (Dlussky, 1967). Their nests look similar to formicaries of red wood ants but differ considerably in the inner structure and the preferred building material, while the peculiar lifestyle of F. exsecta is mirrored in the way in which they use the nest.

The primary structural feature of F. exsecta formicaries, as opposed to red wood ant nests, is that in the former the inner cone is absent. This puts considerable limitations on the size, and first of all height, of F. exsecta anthills. In some cases, F. exsecta ants are able to compensate for the absence of the inner cone by building their nests over various objects, such as stones, logs, young trees, etc.

The second distinguishing feature of F. exsecta nest mounds is different building material. While red wood ants mostly build mounds of needles and branch fragments, F. exsecta ants prefer pieces of herbs and grasses, leaves of shrubs and trees, and lichen thalli (Dmitrienko and Petrenko, 1976). During this work, ants can cut leaf fragments of different size (Goryunov, 2012). The finest pieces of plants are used by F. exsecta for encrusting soil particles which are then fitted into the mound.

A significant amount of soil in the mound itself is yet another essential feature of F. exsecta nests. The underlying bank of the anthill is usually not pronounced, since much soil is used for erecting the mound. Conspicuous banks were only observed by me in Kostroma Province. Several large nests were positioned on “pedestals” that did not look like natural hillocks and were presumably built by ants to avoid overshadowing of the growing colony by tall grass stand.

Soil particles are fitted into the peripheral layers of the mound more densely and in greater amounts than in the center. This results in a hard crust layer 1–1.5 cm thick which protects the colony from rainfall and gives shape to the nest, i.e., serves as armature. The crust layer was absent in all the nests from the upper reaches of the Kolyma River due to a very thin soil layer in that region. For the most part of the growing season, the crust layer is covered with freshly collected plant material (not mixed with soil) which forms a temporary layer. The latter layer is completely incorporated into the former during preparation for winter.

There is an intermediate layer between the mound and the subterranean part of the nest of F. exsecta, which is absent in red wood ant nests. This layer almost exclusively consists of large chambers whose walls are made of soil mixed with numerous fine plant fragments. The intermediate layer is somewhat elevated above the soil surface, its thickness being 6–8 cm.

There is one more group of large chambers in F. exsecta nests. It is situated above, under the vault of the mound. In small anthills, this group is substituted by a single chamber which is very wide and was previously described as the main chamber (Dlussky, 1967) or as the brood chamber (Dmitrienko and Petrenko, 1976).

The mound itself, compared with the crust, consists of a less densely packed and less soil-rich material. Deep within the mound, there are horizontally positioned chambers which are smaller than the uppermost ones.

In summer, the upper chambers and those around the vertical axis of the nest are filled with brood which is sorted by age. Pupae occupy the uppermost chambers with successively younger stages deeper down. Eggs are situated just above the intermediate layer. In addition, the closer chambers are to the intermediate layer, the less they are filled with brood, i.e., the brood rearing zone forms an inverted cone relative to the mound.

Auxiliary Nests

In addition to living nests, F. exsecta ants use auxiliary nests for various purposes. The mound in such nests contains only plant material, because ants do not dig soil in this case. In other words, these nests lack the subterranean part, the intermediate layer, and, as a rule, the crust. Due to the peculiarities of structure and utilization, these nests rarely exceed the diameter of 0.25 m at the bottom. Ants often surround sedge and grass stems with picked and excised plant fragments so that the tussock acts as a backbone to the auxiliary nest.

Auxiliary nests may be temporary and exist only for one season or relatively permanent. Temporary auxiliary nests are more common in large developed formicary complexes of F. exsecta. In such complexes, tens of auxiliary nests emerge every year, and the fraction of auxiliary nests reaches up to 50% of all anthills. Ants often erect series of 2–3 auxiliary nests that form a line running along the sunniest edge of the primary nest (Goryunov, 2007).

The main functions of temporary auxiliary nests are structuring of the foraging area, maintenance of food transport chains (Pisarski, 1972), and provision of shelters for remote foragers. Ants use series of auxiliary nests to choose an optimal site for such a nest (after a month, only one nest from the series remains) or for a new primary nest. When colonizing a new foraging area, F. exsecta ants start with building a network of temporary auxiliary nests and only afterwards they erect primary formicaries. The position of primary nests in the new area may not coincide with the position of initial auxiliary nests. In spring, buffering auxiliary nests may emerge between primary formicaries as relationships between the latter become restored. In case of especially tight relationships, a series of auxiliary nests or a single attenuate gallery-like nest may exist between the primary nests during the whole season.

Besides that, temporary auxiliary nests are used by F. exsecta ants in the process of construction of primary anthills. In this case, the auxiliary nest is built in the vicinity of the main nest or even on its edge. Then the auxiliary nest gradually becomes connected with the primary one by means of a gallery until the mound of the primary nest completely overlays the auxiliary nest. This process may be repeated more than once, which eventually results in a teardrop-shaped anthill.

The functions of permanent auxiliary nests largely coincide with main functions of temporary ones. Permanent auxiliary nests emerge in F. exsecta formicary complexes when environmental conditions and the colony’s structure in the entire complex or in its part remain stable over a long period of time. Most commonly permanent auxiliary nests are built near constant sources of aphid colonies (e.g., trees, shrubs, and perennial herbs). When a permanent auxiliary nest exists long enough it may get covered with crust, but neither the intermediate layer, nor the subterranean part ever appear in such nests.

Relocation of Building Material

It is shown for red wood ant nests that building materials are being constantly relocated within the anthill (Kloft, 1959). F. exsecta ants also move nest material from one place in the anthill to another. However, while in red wood ants the bank and the inner cone determine the shape of the anthill, in F. exsecta the crust layer does so. Therefore, manipulations with nest material in F. exsecta are all the more important.

The most favorable habitats for F. exsecta are rapidly changing transitional ones, such as forest edges, glades, and clearings. Under such conditions, it is important to be able to quickly change the configuration of the nest. By changing the configuration of the crust layer, F. exsecta ants can rather promptly respond to changes in the environment. In the course of the season, the anthill bottom may change its shape from round to oval, or vice versa. An additional top may appear or disappear on the anthill.

Besides that, whole F. exsecta nests can be moved continuously or step-like. At some time, an anthill may become constantly overshadowed by growing vegetation. In such cases, the primary F. exsecta nest may travel a distance of about 1.5 m in several weeks with only the intermediate layer and subterranean part left at the former site. Gradual relocations of primary anthills may last for years with several centimeters traveled each year. After a few years, an anthill may occupy a position where previously there was another one.

Relocation of building material within the nest is easily observable once the nest has been damaged in summer. At this time, the crust is covered with fresh material. When some part of the mound is damaged, ants peel all of the fresh material off and transfer it to the damaged region.

Relocation of building material in F. exsecta ants is not limited to within-nest movements. The mound material, except for the intermediate layer, is an object of exchange between other anthills. This is best observed in manipulations with auxiliary nests.

Auxiliary nests of F. exsecta can be easily erected and dismantled since they consist of plant fragments only. If the auxiliary nest is no longer needed, the ants take its mound apart. The building material can be used for the primary anthill or other auxiliary nests.

The same takes place when ants, for whatever reason, have to leave their primary nest. All of the mound material from the abandoned nest is transferred to one or more neighboring anthills or brought to a new site. Only the intermediate layer and the subterranean part remain in the place of the abandoned nest. Ants may visit the remaining parts of the nest and maintain their functionality. Subsequently a new mound may be erected in the site of the old nest, either over the whole intermediate layer or on a part of it. In any case, abandoned mounds exist for only a short time in developed F. exsecta colonies. Only in colonies situated in the upper reaches of the Kolyma did I observe evidently old abandoned mounds of F. exsecta ants. However, in this region, mounds are almost exclusively built of larch needles that quickly deteriorate as nest material. In addition, anthill mounds at the upper Kolyma contain excised fragments of lichen thalli. There were no lichens in the inspected abandoned nests, which suggests that, for F. exsecta ants, excised material is more valuable than picked-up one.

Besides relocation of the mound and redistribution of material among auxiliary nests, colonies of F. exsecta exhibit background exchange of materials among primary nests. The speed of this exchange may be considerable. Between two neighboring anthills situated 10–20 cm apart (from one bottom edge to the other), transfer of nest material from the most remote edge of one nest to the most remote edge of the other takes about 12 h.

Relocation of building material within the nest and between large (over 60 cm in diameter at the bottom) neighboring anthills may lead to fusion of these nests. There are two scenarios of fusion. When two nests gradually grow or move, at some time their mound bottoms may come into contact. Once this has happened, extensive building and widening of the mounds begin at the joint. Subsequently the two nests may unite under a common mound or retain both mounds. In the future, other neighboring anthills may join the new common nest as well. According to the second scenario, ants build a gallery that connects the mounds of fusing anthills. Underneath the gallery, the intermediate layer and the subterranean part are formed. Subsequently the gallery may be extended and two anthills may fuse as in the first scenario or, alternatively, anthills will remain connected by means of the gallery for quite a long time. It should be noted that fusion by means of a gallery is reversible. After some time, ants may dismantle the gallery and only the intermediate layer and the subterranean part will remain, which will perish after a year without maintenance. I never observed disconnection of the nests that had fused according to the first scenario or any other kind of gradual division of nests.

Seasonal Aspects of Nest-Building

The pattern and intensity of nest-building activity change during the season. Leaf fragments are mostly excised by ants from mid-May to early June; later this behavior is so weakly pronounced that it is almost impossible to find the characteristic damage to grasses and herbs around the anthill.

Approximately three weeks after the ants start to excise plant fragments, the rapid growth of primary anthills and construction of new ones begin. New nests are usually founded before the first third of July. However, if a formicary complex has invaded a new area, construction of new nests may proceed till the end of July, but only in these new territories.

In the middle of and late in the season, the total nest bottom area in F. exsecta colonies practically does not increase. During this period, large formicary complexes lose most of their temporary auxiliary nests. It is common after the swarming of alates (as a rule, early in August) that the total nest bottom area may even decrease. However, nests and their groups may still be changing in size almost till the end of the season.

The middle and the end of the season is a time when ant abundance is redistributed across the whole formicary complex. The movement of ants is accompanied by relocation of nest material and may occur between the neighboring nest groups or in a relay manner from one edge of the complex to the other. In some seasons, redistribution of abundance may affect over one-third of all the inhabitants of the complex (Goryunov, 2009).

Seifert (2000) - Nest mounds are often more structured than in related species. Materials and type of nest construction depend upon insolation, ground water level, soil type, and composition of vegetation. The following type is frequent on mineralic soils: a calotte-like outer hull of the dome, which can often be lifted without breaking (Agosti 1989), is constructed with more dense, strongly adhesive materials (usually finely cut grass pieces). Rather voluminous upper brood chambers (during warm weather the sites for pupae) may be situated between this hull and inner mound material that consists of more lofty plant pieces. The lower mound core is a mixture of humified plant material and mineralic soil. Galleries may reach 150 cm down into the soil. In polygyous nests and during summer, numerous clearly separated chambers of 2 cm width are found below the level of soil surface down to 80 cm. These chambers usually contain a queen, eggs, small larvae, and few workers. In habitats deficient of grasses, other materials as coniferous needles, rabbit pellets, or small pebbles may be used. Nest diameters may reach 200 or even 300 cm (Agosti 1989; Dlussky 1967). In semi-shaded boreal forests, the author observed nest mounds of 150 cm height and 180 cm diameter, the base of which had been abandoned by the ants and covered by mosses (Polytrichum).

Fungi

This species is a host for the ectoparastic fungus Aegeritella superficialis (Espadaler & Santamaria, 2012).

Castes

Queen

Male

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • exsecta. Formica exsecta Nylander, 1846a: 909, pl. 18, fig. 20 (w.q.m.) FINLAND. Combination in F. (Coptoformica): Müller, 1923: 146. Senior synonym of dalcqi, etrusca: Bernard, 1967: 323; of exsectopressilabris: Bernard, 1967: 323; Dlussky & Pisarski, 1971: 194; of kontuniemii, sudetica, wheeleri Stitz: Dlussky, 1967a: 100; Dlussky & Pisarski, 1971: 194; of rubens: Dlussky, 1964: 1027; of nemoralis: Seifert, 2000a: 526. See also: Donisthorpe, 1915d: 273; Parapura, 1972: 763; Kutter, 1977c: 283; Agosti & Hauschteck-Jungen, 1988: 280; Kupyanskaya, 1990: 200; Atanassov & Dlussky, 1992: 282; Seifert, 2000a: 525; Radchenko, 2007: 36.
  • exsectopressilabris. Formica exsecta var. exsectopressilabris Forel, 1874: 52 (w.q.m.) SWITZERLAND. Subspecies of pressilabris: Dalla Torre, 1893: 205. Raised to species: Bondroit, 1912: 352; Bondroit, 1918: 63. Subspecies of exsecta: Karavaiev, 1927c: 284; Karavaiev, 1936: 255; Boven, 1947: 189. Junior synonym of exsecta: Bernard, 1967: 323; Dlussky & Pisarski, 1971: 194.
  • rubens. Formica exsecta var. rubens Forel, 1874: 51 (w.) SWITZERLAND. Raised to species: Bondroit, 1918: 62. Subspecies of exsecta: Ruzsky, 1925b: 43; Emery, 1925b: 257. Junior synonym of exsecta: Dlussky, 1964: 1027.
  • etrusca. Formica exsecta var. etrusca Emery, 1909b: 191, fig. 5 (w.) ITALY. Raised to species: Bondroit, 1918: 64. Subspecies of exsecta: Emery, 1925b: 257; Karavaiev, 1926e: 196. Junior synonym of exsecta: Bernard, 1967: 323.
  • dalcqi. Formica dalcqi Bondroit, 1918: 63 (w.) FRANCE. Subspecies of exsecta: Emery, 1925b: 257. Junior synonym of exsecta: Bernard, 1967: 323.
  • sudetica. Formica exsecta var. sudetica Scholz, 1924: 48 (w.) POLAND. Junior synonym of exsecta: Dlussky & Pisarski, 1971: 194.
  • kontuniemii. Formica kontuniemii Betrem, 1954: 230 (w.) FINLAND. Junior synonym of exsecta: Dlussky, 1967a: 100; Dlussky & Pisarski, 1971: 194.
  • nemoralis. Formica nemoralis Dlussky, 1964: 1037 (w.m.) UKRAINE. Junior synonym of forsslundi: Dlussky, 1967a: 105; of exsecta: Seifert, 2000a: 526.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Nylander 1846. Page 909
Nylander 1846. Page 910
Nylander 1846. Page 911

Worker

Seifert (2000) - Maximum size larger than in other species (CL 1419 ± 82, 1200-1641; CW 1362 ± 83, 1131-1574). Head shape of average Coptoformica type (CL/CW 1.042 ± 0.023, 0.979-1.099); however, long-headed and short-headed specimens may occur within the same nest. Rather long scape (SL/CL 1.008 ± 0.022, 0.931-1.063). Clypeus at least in anterior third, but normally also in median and posterior portions with standing setae (ClySet 3.54 ± 1.08, 2-5). Lateral semierect setae in the ocellar triangle usually present (OceSet 92%). Eye hairs at least in a fraction of the nest population strongly developed, often hook-shaped (EyeHL 27.0 ± 6.5, 0-45; Fig. 10). Pubescence in the occellar triangle frequently dilute, but enormous intraspecific and intranidal variation occurs (sqrtPDF 5.69 ± 0.90, 3.78-9.30). Region of occipital corners with semierect to subdecumbent pubescence (however, in specimens of the etrusca population almost appressed). Craniad profile of forecoxae with semierect setae (nCOXA 8.86 ± 3.89, 0.5-23). Dorsal mesosoma and propodeum occasionally with few standing setae, lateral metapleuron and ventrolateral propodeum more frequently setaceous (nMET 1.86 ± 2.11, 0-9). Outer edge of the hind tibial flexor side conspicuously hairy (nHTFL 10.97 ± 2.82, 5.0-23.0), with two size classes of setae, and subdecumbent pubescence (Fig. 2). Semierect setae on gaster tergites as a rule beginning on the 1st tergite (TERG 1.19 ± 0.46, 1-3); nest sample means of TERG always < 2.4. Pubescence density on first gaster tergite with extreme intranidal and intraspecific variation (sqrtPDG 6.82 ± 1.19, 3.93-9.88).

Queen

Seifert (2000) - Size definitely larger than in other species (CL 1636 ± 44, 1514-1741; CW 1721 ± 42, 1629-1809; ML 2878 ± 116, 2613-3115). Head broad (CL/CW 0.950 ± 0.022, 0.900-1.008), scape long (SL/CL 0.956 ± 0.023, 0.893-1.004). Clypeus at least in anterior third, but normally also in median and posterior portions with standing setae. Lateral semierect setae in the ocellar triangle normally present. Eye hairs normally long and numerous, often hook-shaped (EyeHL 45.6 ± 7.6, 31-69); samples with less numerous eye hairs may occur. Pubescence in the occellar triangle relatively dense (sqrtPDF 4.28 ± 0.49, 3.34-5.75), less variable than in workers. Occipital corners of head normally with semierect smaller setae and pubescence, morphs with almost reduced and such with very developed occipital hairs may occur (OccHD 46.9 ± 22.5, 7-107). Brilliance of dorsal head surface variable, but relatively matt and weakly sculptured surfaces dominate (GLANZ 1.71 ± 0.36, 1.0-2.5). Craniad profile of forecoxae with semierect setae (nCOXA 12.95 ± 4.09, 3.5-23.0). Promesonotum normally with standing setae that clearly differ from semierect pubescence, in weakly haired specimens the differentiation between shorter semierect setae and longer semierect pubescence can be lost (MnHL 181.8 ± 40.0, 0-256). Outer edge of the hind tibial flexor side conspicuously hairy (nHTFL 12.81 ± 3.20, 8.0-22.0), with two size classes of setae and subdecumbent pubescence. Semierect setae on gaster tergites always beginning on the first tergite (TERG 1.00 ± 0.00). Pubescence density on first gaster tergite with extreme intraspecific variation (sqrtPDG 6.17 ± 1.16, 3.83-9.25).

Type Material

Helsinki, Finland. Syntypes 1 male, 1 female, 3 workers (Field Museum of Natural History) [investigated].

References

  • Agosti, D.; Hauschteck-Jungen, E. 1988 [1987]. Polymorphism of males in Formica exsecta Nyl. (Hymenoptera: Formicidae). Insectes Soc. 34: 280-290 (page 280, see also)
  • Atanassov, N.; Dlussky, G. M. 1992. Fauna of Bulgaria. Hymenoptera, Formicidae. Fauna Bûlg. 22: 1-310 (page 282, see also)
  • Bernard, F. 1967a [1968]. Faune de l'Europe et du Bassin Méditerranéen. 3. Les fourmis (Hymenoptera Formicidae) d'Europe occidentale et septentrionale. Paris: Masson, 411 pp. (page 323, senior synonym of dalcqi, etrusca, senior synonym of exsectopressilabris)
  • Collingwood, C. A. 1979. The Formicidae (Hymenoptera) of Fennoscandia and Denmark. Fauna Entomol. Scand. 8:1-174.
  • Dlussky, G. M. 1964. The ants of the subgenus Coptoformica of the genus Formica (Hymenoptera, Formicidae) of the USSR. Zool. Zh. 4 43: 1026-1040 (page 1027, senior synonym of rubens)
  • Dlussky, G. M. 1967a. Ants of the genus Formica (Hymenoptera, Formicidae, g. Formica). Moskva: Nauka Publishing House, 236 pp. (page 100, senior synonym of kontunienmii, sudetica and wheeleri)
  • Dlussky, G. M.; Pisarski, B. 1971. Rewizja polskich gatunków mrówek (Hymenoptera: Formicidae) z rodzaju Formica L. Fragm. Faun. (Warsaw) 16: 145-224 (page 194, senior synonym of exsectopressilabris, senior synonym of kontunienmii, sudetica and wheeleri)
  • Donisthorpe, H. 1915f. British ants, their life-history and classification. Plymouth: Brendon & Son Ltd., xv + 379 pp. (page 273, see also)
  • Espadaler, X., Santamaria, S. 2012. Ecto- and Endoparasitic Fungi on Ants from the Holarctic Region. Psyche Article ID 168478, 10 pages (doi:10.1155/2012/168478).
  • Goryunov, D. N. 2015. Nest building in Formica exsecta ants (Hymenoptera, Formicidae). Zoologichesky Zhurnal. 94:1132-1137. doi:10.1134/S0013873815080035
  • Kummerli R, Keller L (2007) Contrasting population genetic structure for workers and queens in the putatively unicolonial ant Formica exsecta: population genetic structure in ants. Mol Ecol 16:4493–4503. doi:10.1111/j.1365-294X.2007.03514.x
  • Kupyanskaya, A. N. 1990a. Ants of the Far Eastern USSR. Vladivostok: Akademiya Nauk SSSR, 258 pp. (page 200, see also)
  • Kutter, H. 1977c. Hymenoptera, Formicidae. Insecta Helv. Fauna 6: 1-298 (page 283, see also)
  • Müller, G. 1923b. Le formiche della Venezia Guilia e della Dalmazia. Boll. Soc. Adriat. Sci. Nat. Trieste 28: 11-180 (page 146, combination in F. (Coptoformica))
  • Nylander, W. 1846a. Adnotationes in monographiam formicarum borealium Europae. Acta Societatis Scientiarum Fennicae. 2:875-944. PDF (page 909, pl. 18, fig. 20 worker, queen, male described)
  • Parapura, E. 1972. An ergatandromorph Formica exsecta Nyl. (Hymenoptera, Formicidae) from Poland. Bull. Acad. Pol. Sci. Sér. Biol. 20: 763-767 (page 763, see also)
  • Seifert, B 2000a. A taxonomic revision of the ant subgenus Coptoformica Mueller, 1923 (Hymenoptera: Formicidae). Zoosystema. 22:517-568. (page 526, Senior synonym of nemoralis)