Aphaenogaster treatae

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Aphaenogaster treatae
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Stenammini
Genus: Aphaenogaster
Species: A. treatae
Binomial name
Aphaenogaster treatae
Forel, 1886



Specimen Label


Aphaenogaster treatae, unlike many of its North American congeners, is typically found in open habitats such as fields and pine barrens. In Florida it occurs in sandy uplands. It is often difficult to find even where it is known to occur (Deyrup, 2016).

Photo Gallery

  • Aphaenogaster-treatae 0990.jpg
  • Aphaenogaster treatae nesting at the base of a grass clump in sterile, well-drained soil - eastern Missouri, USA (James Trager).


Note flat lobes at the inner bases of each antennal scape.

Aphaenogaster treatae is similar to Aphaenogaster ashmeadi, but has a larger lobe at the base of the scape. The lobe is one-fourth the length of the scape. (DeMarco, 2015)


Deyrup (2016) - This is a large species resembling Aphaenogaster ashmeadi. Both species have a conspicuous lobe at the base of the antennal scape; this might serve to protect the joint at the base of the antennae, but if this is the case, one might expect to see the structure in more species of ants. In treatae, this lobe is thickened, with a distinct lateral face, while in ashmeadi the lobe is thin, although it may look thicker from some angles because its dorsal surface is convex. In peninsular Florida, treatae is reddish brown, while ashmeadi is blackish, but in the Panhandle, both species may be reddish brown.

Keys including this Species



Deyrup (2016) - A. treatae occurs from Ontario south into Florida, west into Michigan, Oklahoma and Texas. In Florida, treatae occurs in sandy uplands from Collier County northward and west through the Panhandle, although there are many large gaps in this distribution. This species is often difficult to find even where it is known to occur.

Distribution based on Regional Taxon Lists

Nearctic Region: United States (type locality).

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


This species nests between clumps of grass in sandy, semi-open areas.


Deyrup (2016) - The following paragraph is summarized from Carroll (1975). Nests are in well-drained sandy soil, generally in open stands of pines and oaks. In Florida, the nest entrances are usually at the base of a clump of grasses or herbs, while in northern parts of its range, treatae is often associated with rocks or logs. Nests have one or two entrances, one of which is usually marked by a small turret of plant debris. Nests go down to approximately 45 cm, with pupae and prepupae in a superficial chamber and larvae in deeper chambers. Foraging is on the surface of the ground, always in open to partially shaded areas. Workers commonly collect arthropods, occasionally collect seeds and bits of Russula mushrooms. Alates are in nests from mid-May through mid-July. Florida colonies usually have approximately 200 workers.

In Michigan, treatae was studied in detail by Talbot (1954, 1966). Nests often had a chamber that was mostly above ground and roofed with a thatch of plant material and soil, presumably for warming pupae or prepupae when the soil temperature was cool. Talbot made a complete inventory of the individuals in 30 nests. Numbers of workers ranged from 65 to 1662, with an average of 682. The locations of nests were also plotted in a sandy, abandoned field. In a study plot 100 feet by 120 feet, there were 63 colonies, providing an average of 32 workers that might forage over every square yard. Alates fly under precisely controlled conditions, when the temperature is 78°F-88°F, the air is calm, the sun is partly or completely obscured by clouds, but the ambient light remains relatively high and there is no rain (Talbot 1966). Alates sometimes wait in the nest entrance and rush out as soon as a cloud obscures the sun. In North Carolina, Carter (1962) found treatae common throughout the state, living primarily in fields and in open forests, and only rarely in closed, mesic forests.






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

  • treatae. Aphaenogaster treatae Forel, 1886b: xl (w.q.m.) U.S.A.
    • Combination in Stenamma (Aphaenogaster): Emery, 1895c: 302.
    • Combination in Aphaenogaster: Wheeler, W.M. 1913c: 114.
    • Combination in Aphaenogaster (Attomyrma): Emery, 1921f: 60.
    • Status as species: Mayr, 1886d: 444; Dalla Torre, 1893: 107; Wheeler, W.M. 1904e: 303; Wheeler, W.M. 1906b: 5; Wheeler, W.M. 1916m: 586; Dennis, 1938: 284; Creighton, 1950a: 153; Smith, M.R. 1951a: 798; Smith, D.R. 1979: 1363; Bolton, 1995b: 73; Coovert, 2005: 51; Ellison, et al. 2012: 233.
    • Senior synonym of wheeleri: Creighton, 1950a: 153.
    • Senior synonym of pluteicornis: Shattuck & Cover, 2016: 14.
    • Material of the unavailable name alabamensis referred here by Creighton, 1950a: 153.
  • pluteicornis. Aphaenogaster treatae subsp. pluteicornis Wheeler, G.C. & Wheeler, E.W. 1934: 7 (w.q.m.) U.S.A.
    • Wheeler, G.C. & Wheeler, J. 1953b: 62 (l.).
    • Combination in Aphaenogaster (Attomyrma): Creighton, 1950a: 154.
    • Subspecies of treatae: Creighton, 1950a: 154; Smith, M.R. 1951a: 798; Smith, D.R. 1979: 1363; Bolton, 1995b: 72.
    • Junior synonym of treatae: Shattuck & Cover, 2016: 14.
    • Material of the unavailable name oklahomensis referred here by Creighton, 1950a: 154.
  • wheeleri. Aphaenogaster treatae subsp. wheeleri Mann, 1915: 51, fig. 1a (w.q.) U.S.A.
    • Subspecies of treatae: Smith, M.R. 1951a: 798.
    • Junior synonym of treatae: Creighton, 1950a: 153; Smith, D.R. 1979: 1363.

Type Material

Note: A specimen (BMNH(E)1013809; CASENT0900414) in The Natural History Museum from Woods Hole, Massachusetts is labelled as a "cotype" but is not a true type as it is not from the type locality.

Taxonomic Notes

The subspecies A. treatae pluteicornis has been described for the population occurring from Alabama into Texas; the two intergrade in Alabama (Creighton 1950), and there is no reason to believe that this subspecies is actually a separate species (Deyrup, 2016).



  • 2n = 42 (USA) (Crozier, 1977).

Name Derivation

August Forel named this species for Mary Treat, who sent him the type specimen, Forel named both mariae and treatae for Mary Treat consecutively in the same 1886 paper (Forel 1886). Some years earlier (1879), Mary Treat published an extensive account of a colony of a slave-making Formica, with detailed descriptions of raids and some preliminary experimental manipulations. Lacking scientific credentials, and perhaps primarily interested in stimulating general interest in the natural history of ants, Treat published her paper in Harper's Monthly Magazine. This article is currently available online, and can be found by entering "A chapter in the history of ants" as a Google query. Treat's observations are still useful and raise some interesting questions, assuming the account is accurate. There are plenty of startling anthropomorphisms, as one might expect for the time, considering that the first volumes of Fabre's Souvenirs Entomologiques (which mark the beginning of our modern understanding of insect behavior) were also published in 1879. This is not to say that insect behavior is widely understood even today. It is common to see a statement that the behavior of ants and other insects is "programmed," without much thought about what kind of programming would enable an insect to make a living in a highly complex, diverse, and inconstant environment.