Polyergus

Life-forms

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Ecdysozoa
Cladus: Panarthropoda
Phylum: Arthropoda
Subphylum: Hexapoda
Classis: Insecta
Cladus: Dicondylia
Subclassis: Pterygota
Cladus: Metapterygota
Infraclassis: Neoptera
Cladus: Eumetabola
Cladus: Endopterygota
Superordo: Hymenopterida
Ordo: Hymenoptera
Subordo: Apocrita
Superfamilia: Formicoidea

Familia: Formicidae
Subfamilia: Formicinae
Tribus: Formicini
Genus: Polyergus
Species: P. breviceps – P. lucidus – P. nigerrimus – P. rufescens – P. samurai – P. texana
Name

Polyergus Latreille, 1804

References

Trager, J.C. 2013: Global revision of the dulotic ant genus Polyergus (Hymenoptera: Formicidae, Formicinae, Formicini). Zootaxa 3722(4): 501–548. DOI: 10.11646/zootaxa.3722.4.5 Reference page.

Polyergus is a small genus of ants with 14 described species. They are also referred to by the names "Slave-raiding ants" or "Amazon ants". They are characterized by their habit of raiding nests (of Formica) for workers.

Reproduction

Polyergus workers are incapable of caring for brood, for the most part due to their dagger-like, piercing mandibles. As such, they have evolved to be parasites on certain species of ants in the genus Formica. They have lost the instinct for carrying out even rudimentary brood care, and even for feeding themselves (which they are unable to do). Polyergus workers exist in essence solely to raid the Formica nests. The captured ants are generally referred to as "slaves" in scientific and popular literature, though recent attempts have been made to apply other human cultural models. Some of these describe the Polyergus as "raiders" or "pirates" or "kidnappers". They describe the Formica workers as "helper-ants", or "domesticated animals". Biologists describe the system as parasitism by "dulosis" (slavemaking) by Polyergus on the host Formica species.

Polyergus obtains its Formica work force by stealing pupae from nearby Formica colonies and carrying them back to its own nest. Back in the Polyergus nest, Formica workers are eventually helped to emerge from the cocoons and pupal exuvia by workers of the same species already living there. The new workers quickly assimilate the characteristic odor of the mixed-species colony — without violence or coercion. The Formica workers that emerge in the mixed-species colony go on to nurse the brood, forage, maintain the nest, feed their adult captors and the queen, and perform other colony upkeep duties.

As far as is known, all established Polyergus colonies have only one queen. However, many contain ergatoids, large, worker-like members with large gasters. These may be substitute reproductive individuals after the queen's death, but this has not been proven. To found a new colony, a lone Polyergus queen invades a nest of the host species, or encounters and moves in with a colony-founding queen of the host species and her first few workers. In the latter case, the host queen is allowed to survive until her little colony has reared a sufficient number of host workers to support the parasite queen, something the Polyergus queen cannot do herself. The young Polyergus queen then kills the existing Formica queen (immediately if sufficient workers are present, later if these are not yet reared) and becomes accepted by the Formica workers. These proceed to rear the first and all subsequent Polyergus brood. Clearly, this complicated and lengthy process often fails, as Polyergus colonies are relatively rare, though each mature colony produces dozens or hundreds of new potential queens each year. To counteract the natural mortality of the Formica worker population, Polyergus workers must conduct regular raids over a 6-8 week period, every summer over the 10- to 15-year lifespan of their colony.[3]
Polyergus lucidus returning from raid on Formica incerta: Three of the Formica ants already incorporated into the mixed colony are visible to the right of the nest entrance.
Species

The genus Polyergus is split up into three groups, or "complexes". There's the lucidus group, the rufescens group, and the samurai group.
lucidus group

Polyergus lucidus Mayr, 1870 – eastern United States, southern Ontario
Polyergus longicornis Smith, 1947 – southeastern United States
Polyergus montivagus Wheeler, 1915 – New England states to northern Florida in eastern United States, southern Ontario, Canada and west to Wisconsin and northern New Mexico, United States
Polyergus oligergus Trager, 2013 – Florida, United States
Polyergus ruber Trager, 2013 – southeastern United States
Polyergus sanwaldi Trager, 2013 – United States, New England west to North Dakota

rufescens group

Polyergus rufescens (Latreille, 1798) – all of Europe, to western China and Kazakhstan
Polyergus breviceps Emery, 1893 – north-central United States, west to Colorado, northern Arizona
Polyergus bicolor Wasmann, 1901 – Wisconsin and Michigan, United States, west to North Dakota and south-central Canada
Polyergus mexicanus Forel, 1899 – Dakotas and Arkansas, to western United States and Canada, and south at high altitude in mountains of Durango, Mexico.
Polyergus topoffi Trager, 2013 – high desert to mid-elevation mountains from Hidalgo, Mexico to southern Arizona, United States
Polyergus vinosus Trager, 2013 – southern California to northern Baja California, Mexico

samurai group

Polyergus nigerrimus Marikovsky, 1963 – Mongolia, Tuvan Republic, southern Russia
Polyergus samurai Yano, 1911 – Japan, Korea, eastern China, southeastern Russia

incertae sedis

Polyergus texanus – excluded from Polyergus by Trager (2013)

References

Bolton, B. (2014). "Polyergus". AntCat. Retrieved 26 May 2020.
"Genus: Polyergus". antweb.org. AntWeb. Retrieved 14 October 2013.

Trager, James C. (2013). "Global revision of the genus Polyergus" (PDF). Zootaxa. 3722 (4): 501–548. doi:10.11646/zootaxa.3722.4.5. PMID 26171540.

Dale Ward (2005). "Ants of Arizona: Polyergus breviceps (Slave Raiding Ant)". Archived from the original on 2011-07-20. Retrieved 2005-10-02.