Formica oreas

This ant nests under stones or logs, usually covered with detritus or thatching, in areas of fine sand to rocky loam. Occasionally this species constructs mounds solely of thatching. Brood was found in nests in March and August, reproductives occurred in nests June to August. Workers are very aggressive when the nest is disturbed.

Identification
The scape is more or less evenly covered with erect hairs, whereas other species have erect hairs only at the tip, with possibly a few others scattered on the scape. It can be separated from others with many erect hairs on the scapes as it has short dense hairs covering the gaster and the gaster is brownish black instead of black. (Mackay and Mackay 2002)

Distribution
Canada, Alberta. United States: Montana, Idaho and south to New Mexico.

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

Habitat
In New Mexico (Mackay and Mackay 2002) - Open woods or meadows up to pine and aspen forests.

Biology
In North Dakota, Sather (1972) found that most colonies formed an integrated cluster of nests, i.e., were polycalic. Workers visited freely between nests and often transferred brood.

Nevada, Wheeler and Wheeler (1986) - Our 16 records represent 12 localities and are widely scattered north of the Hot Desert; 6,200-9,000 ft. Five records were from the Cool Desert and 4 were from the Coniferous Forest Biome. Extensive use was made of thatch in the nest but more eccentrically (both literally and figuratively) than by either Formica obscuripes or Formica obscuriventris. We have described 5 nests as "typical thatch," i.e., either circular or elliptical domes. Two of the nests were polycalic (i.e., had small accessory thatch mounds in the vicinity). One typical dome had decaying wood buried in the thatch. Three nests were under stones, with a small amount of thatch on or beside the stone. One colony had its thatch scattered along a prostrate living trunk of sagebrush. The workers of one colony of F. oreas were tending Obtusicauda artemisicola (Williams) (Homoptera: Aphididae; del. D. Hille Ris Lambers) on sagebrush (Artemisia tridentata) 8 mi. NW Jarbidge (Elko Co.) 6,200 ft. Workers were also tending Obtusicauda nara sp. (Homoptera: Aphididae) on lodgepole pine (Pinus murrayana) in Little Valley (Washoe Co.) 6,400 ft.

Nomenclature

 *  oreas. Formica oreas Wheeler, W.M. 1903e: 643, fig. 2 (w.q.m.) U.S.A. Current subspecies: nominal plus comptula. See also: Wheeler, W.M. 1913f: 458.