Platythyrea punctata

The parthenogenic ant Platythyrea punctata is of general interest biogeographically because it occupies a very large range that extends from south Texas to Costa Rica and from Florida to most islands in the West Indies and the Bahamas. It is not known to occur in Panama, South America or Trinidad and Tobago. Throughout its range it is found in relatively undisturbed, wooded areas and is probably a native species (Deyrup et al., 1988; Deyrup, 2000). A seeming contradiction to this wide distribution is that it would seem to be a very poor disperser. Winged queens have only been found in Florida, the Bahamas and the Dominican Republic (Wheeler, 1905; K. Kellner, unpublished data). Moreover, queens presumably do not fly, because they lack ocelli, possess poorly developed thoraces and wing muscles (Schilder et al., 1999a) and do not appear to be collected in malaise traps (Deyrup & Trager, 1986). Colonies are presumed to reproduce mainly by splitting or fragmenting (fission or budding) and the ants subsequently disperse by walking over land. (Seal et al. 2011)

Distribution
Widely distributed throughout the Caribbean islands, Florida, and Mesoamerica.

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Bahamas, Barbados, Brazil, Colombia, Costa Rica, Cuba, Dominican Republic, French Guiana, Greater Antilles, Guatemala, Guyana, Haiti, Honduras, Lesser Antilles, Mexico, Nicaragua, Panama, Puerto Rico, Saint Lucia, Suriname.



Biology
Brown (1957) reporting in a paper about collections by Robert L. Dressler from Chiapas, Mexico: "from a nest in a fallen log, August 3. Winged forms were present, the males being fully pigmented and apparently active, while most of the females were still in the callow stage or were not yet eclosed. Wilson found this ant foraging on tree trunks after dark in Veracruz and Cuba."

Deyrup, Davis & Cover (2000): This species occurs through the islands of the Caribbean and from Central America north to southern Texas (Brown 1975). The Florida population is currently isolated, though this species might have moved around the Gulf of Mexico to Florida when the climate was warmer. Nests, which often are in dry dead wood, could easily have been shipped to Florida in timber. Unmated workers are able to produce female offspring parthenogenetically (Heinze and Holldobler 1995), so it would be easy to establish a breeding population. Platythyrea punctata is well adapted to disturbed areas, at least in Florida and the Bahamas. The chance that this species was brought by man to south Florida is extremely good; the question is whether such immigrants would have found an indigenous population already established. The first published record that we know of (Creighton 1950) seems rather late for such a large, distinctive species, but these ants are wary and often dart away in the leaf litter before they can be caught.

Reproduction
This ant can reproduce through thelytokous parthenogenesis: mothers can produce diploid, female offspring from unfertilized eggs. Kellner and Heinze (2011) found "that automixis with central fusion and a reduced recombination rate is the most likely mechanism of thelytoky, as in the Cape honeybee and the ant Cataglyphis cursor. Workers in many field colonies from the Caribbean Islands have identical multilocus genotypes and are thus probably clonal."

Reproductive strategy does vary across populations. Colonies in Costa Rica, for example, produce males and reproductives are mated workers. Caribbean populations typically do not produce males.

Haiti
Mann reported finding foragers "running about on the ground in shady places" (Wheeler and Mann 1936).

Nomenclature

 *  punctata. Pachycondyla punctata Smith, F. 1858b: 108 (w.m.) CENTRAL AMERICA. Forel, 1893g: 358 (q.). Wheeler, W.M. 1905b: 81 (l.). Combination in Platythyrea: Roger, 1863a: 173. Senior synonym of cineracea: Brown, 1975: 9; of pruinosa: Wheeler, W.M. 1908a: 123; Brown, 1975: 9.
 * pruinosa. Platythyrea pruinosa Mayr, 1870b: 962 (w.) MEXICO. Forel, 1893g: 358 (m.). Subspecies of punctata: Forel, 1901f: 335; Wheeler, W.M. 1917g: 457; Wheeler, W.M. 1923c: 3. Junior synonym of punctata: Wheeler, W.M. 1908a: 123; Brown, 1975: 9.
 * cineracea. Platythyrea cineracea Forel, 1886b: xxxix (w.) GUATEMALA. Forel, 1899c: 4 (m.). Subspecies of punctata: Forel, 1893g: 359; Forel, 1912c: 35. Junior synonym of punctata: Brown, 1975: 9.

Worker
Length 3 1/4 lines. —Black: the antennae, mandibles, margins of the carinae between the antennae, the legs and apex of the abdomen, ferruginous; the head, thorax, node of the peduncle, and first segment of the abdomen with deep scattered punctures; the insect covered with grey pile; the metatborax truncate, the truncation slightly concave; the node of the peduncle incrassate, elevated to the same height as the first segment, elongated, and forming as it were a basal segment; the apical margin of the first segment ferruginous.

Male
About the same size as the worker, which it greatly resembles, differing in the usual sexual distinctions of a smaller head, larger eyes; the ocelli very bright and glassy; the wings subhyaline, the nervures testaceous, the stigma fuscous.

Type Material
Hab. St. Domingo.