california desert ants

Genus Formica Linné

Formica perpilosa Wheeler
Figures 268, 271, 275

Formica fusca subsp. subpolita var. perpilosa Wheeler 1902b:141; o. Unavailable quadrinomial
Formica perpilosa: Wheeler 1913b:421; o _ _. First available use Cole, 1942:376, 378; o. Wheeler and Wheeler 1986:79. Allred, 1982:474. Cockendolpher and Francke 1990:43.
Formica (Raptiformica) perpilosa: Creighton 1950:463, 467;
o. Gregg 1963:611?613; map; o.

     RANGE: Kansas to Texas, west to California; northern Mexico.

     DESERT RECORDS. Map 20. Inyo Co.: Salt Lake, 1060', Saline Valley, 23 Mar, 7 June 1976 (DG; LACM); sand dunes, 1150', Saline Valley, 8 July 1976 (DG; LACM): Artesian Spring, 1100', Saline Valley, 4 May 1976 (DG; LACM); Willow Creek, 2400', Inyo Mts., 17 Mar 1976 (DG; LACM); Shoshone, 1600', 2 May 1970 (I. Savage;
CDFA). Kern Co.: Randsburg Rd., ca. 4.9 mi W Last Chance Cyn. Rd., 16 Sept 1978 (RRS & CDG, #78? 70; LACM). Los Angeles Co.: Lancaster (60th. & G St. East), 27 Feb. 1990 (G. Mark; LACA). Riverside Co.: Whitewater Cyn., 1800', 12 Oct. 1994 (RRS, #94-51; LACM). San Bernardino Co.: Yermo, 1935', 7 Sept 1952 (RRS; LACM); 0.5 mi E Newberry Springs, 17 Sept, 1978 (RRS & CDG,#78?79, 80; LACM); Morongo Valley, 2600', 30 June 1963 (M. E. Irwin; LACM); Twentynine Palms, 1855', 3 Aug 1933, 9 Aug 1946 (P. H. Timberlake; UCR).

     DISCUSSION. The clypeal structure, shiny integument and long, flexuous body hairs make this ant easily recognized among our species of Formica. The ant occurs also in coastal southern California.
     This is a largely Riparian Community species, occurring at elevations between 1000 and 2600 feet. We have records, however, from Creosote Bush Scrub, Saltbush Scrub and Joshua Tree Woodland. Nests have low mounds and are often situated at the base of a shrub or tree (Cole, 1934) along desert stream bottoms (Creighton, 1950).
     The ant is omnivorous and an aggressive forager. According to Whitford (1978a) F. perpilosa is nocturnal near Las Cruces, New Mexico. We found it foraging at midday at Newberry Springs in May and it is the experience of RRS that the species is normally
diurnal even in the hot part of the year, not only in California, but in New Mexico and Arizona as well.
     The braconid wasp, Elasmosoma vigilans Cockerell, is a known ant parasitoid; it has been observed "darting at" workers of F. perpilosa at Las Vegas, Nevada (Wheeler and Wheeler, 1986). The known hosts for Elasmosoma are all in the genus Formica and E. vigilans or some other species may be expected to be associated with one or more of our desert Formica.