california desert ants

Genus FORELIUS Emery

Forelius mccooki (McCook)
Figures 00-00

     Formica foetida Buckley, 1866:167; o _. (Preoccupied).
     Iridomyrmex MacCooki Forel, 1878:382 (nomen nudum).
     Iridomyrmex mccooki: McCook, 1879:187; o. First available use. Forel, 1886:39; o. Mayr, 1886b:432; o _.
     Forelius maccooki: Emery, 1888:389; o. Wheeler, 1901:520. M. Smith, 1947:595; pl. 17 Fig. 63; o. Shattuck, 1993:---. Bolton, 1995:
     Forelius foetidus: Wheeler, 1902e:14. Emery, 1912:35; pl. 1 fig. 18; o. Creighton, 1950:345; pl. 46; o _ _.
     Forelius Mac Cooki stirps Andrei Forel, 1912:44; o.
     Forelius foetida: Gregg, 1963:434?436; map; o. Wheeler and Wheeler, 1973:102?103; o. Allred, 1982:461. Wheeler and Wheeler, 1986:56?57.

     RANGE: Arkansas, Kansas, southeastern Colorado, central Texas west to southern California; south to central Mexico. Although Cuezzo (2000) included Jamaica in the distribution of this species that record is almost certainly spurious.

     DESERT RECORDS. Map 6. Sporadic through much of our area,
most abundant in Colorado Desert; 27 records.

     DISCUSSION.
      The only ant with which this species can be confused is F. analis. Both ants are similar in size, color and habits. In the field, the two cannot be distinguished from one another.
      The pattern of erect hairs in F. mccooki is quite variable and in some samples the number may be greatly reduced. Such could be mistakenly identified as F. analis. There always are at least a few erect hairs along the side of the head, on the vertexal corner and at least 6 on the pronotum of F. mccooki. The pronotum of F. analis has 2 or 4 erect hairs and there are none on the side of the head or on the vertex corner. The average size of F. mccooki is a little smaller than that of F. analis.
      This species has been collected at desert localities at elevations ranging from -22' to 3500'. It can be found in a variety of situations and exhibits a tolerance for all sorts of soil types, from fine sand of dune areas to the coarse gravel of desert washes and to powdery soil in alkali flats. Plant community associations include Palm Oases, Wash Woodlands, Saltbush Scrub, Alkali Sink Creosote Bush Scrub and Joshua Tree Woodlands.
      Nest tumuli generally consist of scattered or irregular piles of fine sand (Fig. 383). However, there may be a cluster of fairly well defined small (usually no more than 8 cm diameter) craters. This species also nests under stones. In this situation comminuted sand from the nest may be detectable at the base of the stones.
      The workers have been observed foraging on the deserts from as early as 0830 to as late as 1730. They are capable of moving very rapidly and thus are found foraging at high surface temperatures (up to 66°C) when other ants have ceased such activity.
      Their debris piles indicate that they apparently scavenge dead individuals of many other ant species. Other arthropods taken include Hemiptera (Miridae), Diptera (Muscidae) and Homoptera (Cicadellidae, Membracidae). They have also been commonly observed on road kill vertebrates. Other workers are quickly recruited when a new resource is discovered and, by virtue of large numbers and effective chemical defenses, F. mccooki may exclude other ant species.
     This species has been observed foraging for nectar on Chamaesyce spp., Cleomella obtusifolia, Encelia farinosa, Opuntia bigelovii, Sphaeralcea ambigua, Asclepias erosa, and Salsola iberica.