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Extant: 1 valid subspecies
Australia: Queensland: S. geminata may have been eradicated from Queensland but since new infestations are to be expected, we thought it prudent to keep the species on the list.
Solenopsis geminata is the tropical fire ant. Fire ants are a group of related species, the Solenopsis geminata group, that has its center of diversity in southern South America. Solenopsis geminata is the only member of the group that occurs in Costa Rica, although it occurs in a "red form" that is more abundant in open areas and a "black form" that prefers forested areas. The environmental or genetic determinants of these forms are unknown.
Solenopsis geminata is most abundant in open sunny areas. It is common in agricultural areas and around human settlements. In the lowlands it is found not only in the open but may also penetrate into forest understory, albeit at lower density. At higher elevations it is restricted to open areas and does not extend into closed-canopy forest. There is anecdotal evidence that S. geminata occurrence in forest understory, even in mature forest habitats, is increasing, perhaps due to effects of fragmentation. Increased abundance in forest understory could be due to a greatly increased source population in the surrounding pasture areas, or to microclimate change that favors fire ant establishment in the forest understory.
Solenopsis geminata colonies are large, with tens to hundreds of thousands of workers. Nests are in the soil, usually in the form of a large exposed soil mound. Galleries extend out into the surrounding soil, surfacing at foraging zones at a distance from the nest. Most foraging is at the soil surface, but I have seen fire ants foraging several meters up on tree trunks or treefalls when there are abundant epiphytes and epiphytic soil. Workers form galleries extending from the ground up through the epiphytic soil.
Workers are generalized scavengers and they recruit rapidly to resources. Oil and protein sources, such as tuna baits, are particularly attractive. When large resources are discovered, workers often rapidly cover them with soil. I once observed S. geminata workers tending petiolar extrafloral nectaries at each leaf of a long Passiflora vine. The vine looped from the vegetation down to the ground for part of its length, and wherever a leaf petiole was touching the ground the ants had built a soil pavilion covering it.
Workers have powerful stings and are the bane of children running barefoot in the grass. If you mistakenly stand on a nest, workers will slowly cover your feet and lower legs and then all sting at once. Farmers generally despise them.
Individual colonies have large nuptial flights, with abundant males and alate queens issuing from nests. Workers swarm over the nest surface and surrounding vegetation, and they appear to be driving the males and alate queens from the nest. Nuptial flights do not seem highly syncronized among colonies and they may occur at any time of year.
Trager, J. C. 1991. A revision of the fire ants, Solenopsis geminata group (Hymenoptera: Formicidae: Myrmicinae). Journal of the New York Entomological Society 99:141-198.
|Solenopsis geminata||Forel, A., 1893, Formicides de l'Antille St. Vincent. Récoltées par Mons. H. H. Smith., Transactions of the Entomological Society of London 1893, pp. 333-418: 396-398, (download)||396-398||3948|
|Solenopsis geminata||Crawley W. C., 1915, Ants from north and south-west Australia (G. F. Hill, Rowland Turner) and Christmas Island, Straits Settlements. Part 2, Ann. Mag Natur. Hist. 15, pp. 232-239: 239, (download)||239||6192|
|Solenopsis geminata||Emery, C., 1893, Voyage de M. E. Simon à l'île de Ceylan (janvier - février 1892). 3 e Mémoire. Formicides., Annales de la Société Entomologique de France 62, pp. 239-258: 5, (download)||5||3767|
|Solenopsis geminata||Santschi, F., 1913, Glanure de fourmis africaines., Annales de la Societe Entomologique de Belgique 57, pp. 302-314: 5, (download)||5||3723|
|Solenopsis geminata||Wild, A. L., 2007, A catalogue of the ants of Paraguay (Hymenoptera: Formicidae)., Zootaxa 1622, pp. 1-55: 42, (download)||42||21367|
|Solenopsis geminata||n. sp.||Santschi, F., 1915, Nouvelles fourmis d'Afrique., Annales de la Société Entomologique de France 84, pp. 244-282: 258-259, (download)||258-259||3651|
|Solenopsis geminata||Forel, A., 1908, Fourmis de Costa-Rica, récoltées par M. Paul Biolley., Bulletin de la Societe Vaudoise des Sciences Naturelles 44, pp. 35-72: 45, (download)||45||4014|
Found most commonly in these habitats: 95 times found in tropical rainforest, 71 times found in 2º lowland rainforest, 41 times found in urban/garden, 66 times found in montane wet forest, 65 times found in cloud forest, 14 times found in coastal scrub, 49 times found in lowland wet forest, 30 times found in edge of cloud forest, 26 times found in mature wet forest, 22 times found in mesophil forest, ...
Found most commonly in these microhabitats: 399 times at bait, 295 times ex sifted leaf litter, 15 times sweeping, 46 times ground forager(s), 18 times under stone, 25 times Hojarasca, 24 times beating vegetation, 1 times BL/MV lights, 19 times under rock, 12 times forest litter, 1 times fallen fruit, ...
Collected most commonly using these methods: 391 times Baiting, 185 times MiniWinkler, 26 times sweeping, 73 times search, 63 times Winkler, 71 times MaxiWinkler, 42 times Beating, 46 times Berlese, 18 times hand collecting, 30 times hand collection, 26 times Mini Winkler, ...
Elevations: collected from 1 - 2270 meters, 570 meters average
Type specimens: Holotype of Crematogaster laboriosus: casent0901432; Holotype of Myrmica mellea: casent0901431; syntype of Atta clypeata: casent0902348; syntype of Myrmica glaber: casent0902347; syntype of Myrmica laevissima: casent0901430; syntype of Myrmica polita: casent0902346; syntype of Solenopsis eduardi bahiaensis: casent0917011; syntype of Solenopsis geminata galapageia: castype00445-01, castype00445-02, castype00445-03; syntype of Solenopsis mandibularis: casent0901969; syntype of Solenopsis edouardi bahiaensis: casent0913893; syntype of Solenopsis edouardi perversa: casent0913896, casent0913897; syntype of Solenopsis eduardi: casent0908793; syntype of Solenopsis geminata innota: casent0913894, casent0913895; syntype of Solenopsis geminata nigra: casent0908794