Pogonomyrmex

These ants are common New World ants that are found in arid habitats. Most species are seed harvesters, others feed on a variety of items, especially dead or dying insects. Large quantities of seeds may be stored in their nests. Most species have a large psammophore or beard of coarse hairs on the ventral surface of the head, which are used to carry fine sand during the excavation of the nest. Large mating flights occur in late summer, usually after a rain on the previous day (Mackay, 1981). Some species build large, conspicuous mounds and clear the vegetation from around the nest. Most species in this genus can deliver very painful stings. (Mackay and Mackay 2002)

Identification
Key to South American Pogonomyrmex

Key to North American Pogonomyrmex

There is currently one species known from Central America (i.e., as defined beginning south of Mexico; Taber's key to North America species includes Mexican species): Pogonomyrmex guatemaltecus. This ant is presently known from Guatemala and Mexico. There are three validly named species from the Caribbean. All of these species are Hispaniola endemics and all are considered to be in the subgenus Ephebomyrmex (see this key couplet: 11E).

Species richness
Species richness by country based on regional taxon lists (countries with darker colours are more species-rich). View Data



Biology
The genus Pogonomyrmex is the preeminent group of harvesting ants in North America, where it nearly blankets the arid regions of Mexico and the western United States. As is true of other harvesting ants, the workers of this genus collect seeds for food, "harvesting" the plants in their nesting areas by snipping off the seeds with their mandibles. Husked within the nest and stored in subterranean or mound chambers, these highly nutritious seeds become the paramount food for the society, sustaining the ants even through the winter. Seeds are not their sole food, however, because the ants are scavengers as well as harvesters. Although their victims are chiefly arthropods, the workers may transport a varied array of dead booty to their nests.

The nests themselves are constructed in the soil, generally in areas fully exposed to the sun. Some are beneath stones, whereas others are surmounted by soil craters or by small to huge mounds with or without coverings of gravel. In addition, the workers of some species alter the area peripheral to the nests by clearing away the plants-felling them, bit by bit, with their powerful mandibles. Such mounds with their surrounding denuded area, characteristic of the western harvester, are familiar sights to travelers in the arid West.

Although the workers of some species of Pogonomyrmex are extremely hostile and will vigorously attack and sting an invader, other species are contrastingly inoffensive and retiring. The effects of a sting can be very painful. Localized swelling and inflammation ensue rapidly. Soon thereafter a throbbing pain, which may last for several hours, extends to the lymph nodes of the inguinal, axillary, or cervical area, depending on the location of the sting. Frequently, the skin around the wound becomes very moist. Multiple stings will produce excruciating pain and may induce systemic disturbances of considerable severity. Victims who are hypersensitive to the ant venom may collapse from anaphylactic shock and be in grave danger if not given prompt medical attention.

Considerable economic importance has been attached to this genus not only because of the stinging characteristics but also because some of these harvesters may procure seeds in abundance from cultivated crops and may also damage range lands when their nests are numerous. In the United States four species are so outstanding in these respects that the Entomological Society of America has approved common names for them. These are: the western harvester ant (Pogonomyrmex occidentalis), the red harvester ant (Pogonomyrmex barbatus), the California harvester ant (Pogonomyrmex californicus), and the Florida harvester ant (Pogonomyrmex badius).

Nomenclature

 *  POGONOMYRMEX [Myrmicinae: Myrmicini]
 * Pogonomyrmex Mayr, 1868b: 169. Type-species: Formica badia, by subsequent designation of Wheeler, W.M. 1911f: 170.
 * Pogonomyrmex senior synonym of Ephebomyrmex, Forelomyrmex (and the junior homonym Janetia Forel): Lattke, 1991a: 305; Bolton, 1994: 106; Bolton, 1995b: 28; Fernández & Palacio, 1998: 1649; Bolton, 2003: 223.
 * EPHEBOMYRMEX [junior synonym of Pogonomyrmex]
 * Ephebomyrmex Wheeler, W.M. 1902c: 390 [as subgenus of Pogonomyrmex]. Type-species: Pogonomyrmex naegelii, by subsequent designation of Wheeler, W.M. 1911f: 163.
 * Ephebomyrmex subgenus of Pogonomyrmex: Wheeler, W.M. 1910g: 140; Emery, 1921f: 48; Wheeler, W.M. 1922a: 660; Gallardo, 1932b: 94; Kusnezov, 1949c: 293; Creighton, 1950a: 132; Kusnezov, 1951a: 245; Smith, M.R. 1951a: 794; Kusnezov, 1956: 118; Smith, M.R. 1958c: 115; Kusnezov, 1964: 56; Smith, M.R. 1967: 351; Cole, 1968: 22; Smith, D.R. 1979: 1357; Mackay, Mackay, Dominguez, et al. 1985: 42.
 * Ephebomyrmex as genus: Creighton, 1957a: 54; Kusnezov, 1960b: 350; Kempf, 1972a: 106; Brown, 1973b: 180; Snelling, R.R. 1981: 395; Wheeler, G.C. & Wheeler, J. 1985: 257; Dlussky & Fedoseeva, 1988: 79; Hölldobler & Wilson, 1990: 13; Taber, 1998: 146.
 * Ephebomyrmex junior synonym of Pogonomyrmex: Lattke, 1991a: 305; Bolton, 1994: 106; Bolton, 1995b: 28; Fernández & Palacio, 1998: 1649; Bolton, 2003: 223.
 * FORELOMYRMEX [junior synonym of Pogonomyrmex]
 * Forelomyrmex Wheeler, W.M. 1913a: 80 [as subgenus of Pogonomyrmex]. Replacement name for Janetia Forel, 1899c: 61 (footnote). [Junior homonym of Janetia Kieffer, 1896: 236 (Diptera).]
 * Forelomyrmex raised to genus: Taber, 1990: 307.
 * Forelomyrmex junior synonym of Pogonomyrmex: Lattke, 1991a: 305; Bolton, 1994: 106.