Formica archboldi M. R. Smith

Trager, J. C., MacGown, J. A. & Trager, M. D., 2007, Revision of the Nearctic endemic Formica pallidefulva group., Advances in ant systematics (Hymenoptera: Formicidae): Homage to E. O. Wilson - 50 years of contributions. (Memoirs of the American Entomological Institute 80), pp. 610-636 : 614-616

Formica archboldi M. R. Smith , 1944

Figures 4 d, 5 d, 6 d

Formica pallidefulva subsp. archboldi Smith , M. R., 1944: 16. [Examined. Syntype workers] four workers on two pins, labeled, Florida: Archbold Biological Station , 10 miles south Lake Placid , Fla. X- 7 - 43 T. C. Schneirla. Paratype No. 56765 U. S. N. M. ( MCZ) .

Formica (Neoformica) archboldi Creighton , 1950: 549. Raised to species.

DIAGNOSIS

Worker The most evidently sculptured and the smallest member of the group, characteristic of Florida's upland pine and scrub habitats. F. archboldi has the largest eyes relative to head size of all species in this group (see OI, Table 1). Head and gaster very dark reddish brown, appearing blackish or dark gray-brown in the field; mesosoma often a little lighter than head, and sometimes both lighter than gaster. Gastral dorsum at most weakly shining, sheen dulled by numerous, shallow impressions (foveolae) and appressed pubescence composed of moderately dense grayish appressed microchaetae (Fig. 4 d). Dorsal sclerites of mesosoma and gaster usually with moderately abundant, short, erect, brownish-gray erect macrochaetae, and pale grayish appressed microchaetae. Erect macrochaetae on mesosoma and usually on gaster are relatively short, straight and flattened with rounded, blunt or abruptly tapering tips; less often, at least some of those on gaster a bit longer and slightly curved, these less flattened and tapering.

Queen Color, gastral pubescence and sculpture like the workers, with the usual differences in size. There is tessellation on the upper portion of head, pronotum, sides of mesothorax, propodeum and gastral dorsum; wings, when present, clear brownish to clear smoky gray. Pilosity longer and more flexuous than that of worker.

Male Pubescence and pilosity abundant; mesosomal dorsum dull-punctate; entire body black, legs reddish brown or mesosoma lighter, dusky yellowish brown; wings clear brownish to clear smoky gray; pilosity like that of queen; gastral pubescence pale brownish yellow and very dense. Averages smaller than the otherwise difficult-to-distinguish males of F. dolosa and F. biophilica .

DISTINGUISHING FEATURES

Although a sample of this species in the Mayr collection is placed among his schaufussi (anything in the group which was not typical F. pallidefulva is so placed in that collection), this dark brown to nearly black species has rarely been misidentified since its description in 1944 and is unlikely to be confused with any congener in the field. Mounted specimens that are shinier and less pilose than normal, or mislabeled ones (like those from Virginia in the Mayr collection), might be confused with darker color variants of F. incerta or F. pallidefulva without careful inspection. Occasionally other species, especially F. biophilica , may stain black when mounted on pins, which could lead to confusion with F. archboldi .

ETYMOLOGY

This species is named after Richard Archbold, founder of Archbold Biological Station, Lake Placid, Florida, the type locality.

RANGE AND HABITAT

Originally described from Archbold Biological Station in Highlands Co., Florida, this species in fact appears to be more abundant in northern Florida. It is a characteristic ant of the uplands of peninsular Florida and the eastern panhandle, and also recorded by D. R. Smith (1979) as occurring in Georgia and Alabama. One collection in the Mayr collection labeled Virginia is doubtless mislabeled. This ant is characteristic in relatively undisturbed, long-leaf pine sandhills and in scrub or sand pine woodland. Less often it may be found in the transition between these more open sandy habitats and drier portions of flatwoods, or southern live oak woodlands. In northern Florida, F. archboldi coexists with F. dolosa and F. pallidefulva in sandhill vegetation, but to the south on the Lake Wales Ridge (including the type locality), this ant becomes more typical of moist soil among pond-edge vegetation in swales within the white sand scrub vegetation, and is largely replaced in sandhill woodland by F. pallidefulva . It is also reported from sandhill locations along the South Florida coasts, but probably is lacking from the Everglades.

SPECIMENS EXAMINED

FLORIDA: Alachua; Baker; Citrus; Collier; Duval; Hernando; Highlands; Hillsborough; Jackson; Leon; Levy; Liberty; Marion; Okochobee; Pasco; Putnam; Sumter; Suwannee; Volusia; Wakulla.

D. R. Smith (1979) reports F. archboldi from ALABAMA: no county listed. GEORGIA: no county listed.

NATURAL HISTORY

Within the pallidefulva group, this species is the most sensitive to human development and habitat alteration. During eight years of residence in Gainesville FL, J. Trager watched this species slowly disappear from sandhill woodland habitats near new housing developments, even when efforts were made to protect the native vegetation in green space around the houses. On the other hand, at Devil's Millhopper Geological State Park during the same years, ecological restoration efforts consisting of selective species removal (cutting down mesic-adapted trees) and introduction of prescribed fire to maintain the open vegetation structure, resulted in a resurgence of F. archboldi (and incidentally, F. dolosa ) in the upland habitats of the site. A healthy population of F. archboldi could be considered an indicator of high natural area integrity, or at least a low level of habitat degradation, in Florida's pine and pine-oak woodlands.

Nests are usually located beneath wiregrass clumps (or beneath beard grass or sedges in scrub habitats), and occur less frequently in bare soil, at the base of a shrub or under oak-leaf litter. The entrance is often marked with a small accumulation of plant fragments and / or grasshopper dung. Returning foragers watched for ½ - hour intervals in the afternoon foraging period typically brought in more of these plant fragments and dung pellets than they did prey items (J. Trager, unpublished). Worker pupae are typically enclosed in a light tan cocoon, sexual pupae in a darker, thicker cocoon. This species is the host of the small, dull variant of Polyergus lucidus that uses F. archboldi as its host in Florida (Trager & Johnson, 1985). F. archboldi lives outside the range of dulotic or other parasitic Formica species.

The cricket Myrmecophila pergandei Bruner commonly inhabits the nests of F. archboldi . Outside the nest, F. archboldi gathers honeydew from living plant surfaces and from leaf litter, and also actively tends and defends Cinara aphids and Toumeyella scales on grass-stage longleaf pine saplings. The defense by F. archboldi as they tended scales was used to induce workers to attack a termite offered on the end of a pine needle, then following the light-bodied prey as a marker to follow as the worker returned to its nest. In two cases, this resulted in the discovery of a colony of the Polyergus lucidus variety mentioned above.

Foraging occurs mainly between 8 a. m. and noon and between 4 p. m. and dusk, from March through October. However, hemipteran colonies are tended around the clock. Peak foraging activity occurs from April through June. Returning foragers carry a variety of freshly killed insects into the nest. Most of these prey items are herbivorous insects, but also among them are occasional individuals of Odontomachus brunneus Patton . Just how it is that this smaller and less ferociously built Formica captures and kills this well-armed ponerine has not been observed. Trager & Johnson (1985) report on habits of F. archboldi .

Sexuals occur in the nests from late April through June. The alates are not attracted to lights. They apparently fly in early morning, around sunrise. Females must quickly dealate and sequester themselves, as it appears no one has ever found either a newly mated female or incipient colony of this locally abundant ant.