Formica microgyna

Nests are found under stones and logs, occasionally with thatching. Reproductives were found in nests in August. This species enslaves Formica argentea, Formica fusca, Formica lasioides and Formica neogagates. (Mackay and Mackay 2002)

Identification
Robust, large bodied workers, bicolored (head and mesosoma red, gaster black), with numerous blunt, erect hairs on various body parts, especially the pronotum. The tibiae have erect hairs on all surfaces, including a double row on the flexor surfaces. The gaster is dull, except for a band at the end of each tergum, the surface is dull and covered with dense, appressed pubescence. The erect hairs are white, silver or pale yellow in color, and are abundant, especially on the pronotum, mesonotum, propodeum and gaster. Those on the gaster vary in length. Most of the hairs on the mesosoma are blunt tipped, or even weakly spatulate. (Mackay and Mackay 2002)

The queen is a tiny specimen, about two-thirds the size of the largest worker. The scape and tibiae have numerous suberect and erect hairs, as do all surfaces of the head, the dorsum of mesosoma, the petiole, and the dorsum of the gaster. The hairs are longer than those of the major worker, with sharper tips.

The numerous erect hairs on the tibiae would separate this species from most of the others, except for Formica impexa. It can be separated from the latter species, as the propodeum is higher and the erect hairs on the gaster are of several different lengths. It is possible that F. impexa will be shown to be a synonym when more material becomes available.

Distribution
Canada, Alberta. United States. Wyoming south to New Mexico, west to Utah.

Distribution based on Regional Taxon Lists
Nearctic Region: Canada, United States. Neotropical Region: Mexico.

Habitat
In New Mexico (Mackay and Mackay 2002) - Meadows and open forests, pine and aspen forests.

Biology
In Colorado, Gregg (1963) found this species in coniferous forests, mixed forests, and foothill meadows; nests were under stones or wood, in rotten wood or in thatch. Hosts for Formica microgyna: Formica argentea, Formica lasioides and Formica neogagates.

Nevada, Wheeler and Wheeler (1986) - We have 6 records from 5 localities. One was in Sarcobatus Subclimax in the Cool Desert and one was in the Alpine Biome. Both of these were nesting under half-buried stones.

Nomenclature

 *  microgyna. Formica microgyna Wheeler, W.M. 1903e: 645, fig. 3 (w.q.m.) U.S.A. Senior synonym of recidiva: Creighton, 1950a: 504. See also: Wheeler, W.M. 1903f: 656; Wheeler, W.M. 1913f: 465; Letendre & Huot, 1972: 117.
 * recidiva. Formica microgyna var. recidiva Wheeler, W.M. 1913f: 395 (in key) (w.) U.S.A. [Formica microgyna subsp. microgyna var. recidiva Wheeler, W.M. 1913f: 467 (w.m.); unavailable name.] Subspecies of microgyna: Wheeler, W.M. 1917a: 542. Junior synonym of microgyna: Creighton, 1950a: 504.