Genus Polyergus - Amazon Ants

(Amazon) Slavemaking Ants

(Amazon) Slave-raiding Ants

poly-EHR-goos or polly-ER-gus (polly-ER-jiss also heard, but not preferred)

Polyergus Latreille, 1804

Traditionally called "Amazon ants" in much of the older literature, by scholars who had a true liberal arts education, the reference being to the mythical warrior women. This allusion is now lost on many people, who are more familiar with the Amazon River and its basin, or with amazon.com.

Polyergus is a somewhat ironic name meaning "much-work". Certainly, the vigor with which they pursue their brood-robbing raids on host Formica colonies is very impressive, but other than this, they do no work, and cannot even feed themselves, depending entirely on soliciting regurgitated food from host workers for their nutrition.

3 Eurasian spp. in two species groups + 11 North American species, the latter arranged in two species groups. (See Taxonomy for specifics.)

Note: There may be additional species in the West. See remarks under P. mexicanus for details.

4-7 mm (Smith 1947)

Easily recognized by falcate mandibles, often shining yellowish-red to reddish-brown body (occasionally bicolored with darker gaster), thick petiole, and clavate antennal scapes (Smith 1947)

Holarctic; in NA:

Always in mixed colonies with a host Formica sp. Hosts are one (or rarely more) local Formica species of the fusca, pallidefulva or neogagates group. Nests often appear, on casual inspection, like an unusually large nest of the host species.

Typically observed during their spectacular late-afternoon brood-robbing excursions in July or August. Rarely seen outside the nest otherwise. Mating flights are in the latter half of the raiding season.

Rely on liquid food regurgitated to them by their host Formica species.

Colonies are founded by single mated Polyergus queens that enter a host Formica sp. colony, kill the host queen, and become accepted as the replacement queen by the Formica workers. Later, new host workers are added to the permanently mixed species population through raiding nearby host colonies and bringing home brood, mostly pupae. Sexual brood is not retrieved in these raids. Some of the plundered brood is eaten by host workers back at the Polyergus nest. The rest of the plundered brood is reared to adulthood to maintain a host or "slave" worker force. Unable to feed or care for brood on their own, the non-breeding caste (morphological workers) of Polyergus must maintain and increase their mixed colonies by capturing brood of the host species. The adults of the Formica comprise the nest- and brood-care and forager work force of the Polyergus colony in all the usual anty ways.

The "slave-makers" are a storied group of ants, certainly among the most studied and published of any non-pest species. Their habits were first vividly described by the Swiss entomologist Pierre Huber in 1810. The conspicuous, late-afternoon brood-robbing raids on their host Formica species attract the attention of even those with little interest in insects. Internet references below give current additional information.

The various Polyergus species, currently thought to be fourteen worldwide, usually raid and only cohabit with certain Formica species. The degree of host specificity varies from only one host species, to several related species.

M. R. Smith's taxonomic revision of North American species, also available online as Smith 1947, was the standard reference until the recent publication of a global revision by Trager (see below).

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