Pheidole jelskii

P. jelskii is a species that nests in bare soil and open spaces. As such it is well adapted to disturbed habitats of all kinds, from cultivated fields to pastures to roadsides, as well as marginal natural environments such as beaches and river banks. In many places it is extremely abundant, although colony densities vary locally. In the early 1890s H. H. Smith (in Forel 1893j) encountered it only twice on St. Vincent, which given the intensity of his collecting, suggests relative rarity, whereas in the 1990s Stefan Cover and I found it ubiquitous and in dense populations in the nearby islands of Grenada and Barbados. Mature colonies are large, with worker populations numbering into the many hundreds or even thousands. They typically construct conspicuous crater nests with slit-shaped entrances in open soil, but also less regular nests with irregular entrances in vertical banks of soil in heavily disturbed locations. The minors forage singly over distances of up to ten meters or more, and are extremely swift and efficient at laying odor trails over even very loose soil to recruit other minors as well as majors to dead insects and sugar baits. The majors release a strong fetid odor, possibly from skatole, when the colonies are disturbed. (Wilson 2003)

Identification
See the extensive discussion by Wetterer et al. (2015) in the identification section of Pheidole obscurithorax and the description and images by Wilson (2003) in the nomenclature section below.

Distribution
Widespread throughout the West Indies, thence south through South America to southeastern Brazil and northern Argentina. (Wilson 2003)

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Barbados, Brazil, Dominican Republic, French Guiana, Greater Antilles, Grenada, Haiti, Netherlands Antilles, Paraguay, Saint Lucia, Trinidad and Tobago.

Biology
Wheeler (1905), Bahamas - This species is carnivorous. Its nests are flat moundlets, about four inches in diameter, built in sandy, grassy places. The soldiers have the rank odor so characteristic of the ants belonging to the genus Eciton.

Worker
Minor

Major

Nomenclature

 *  jelskii. Pheidole jelskii Mayr, 1884: 34 (s.w.) FRENCH GUIANA. Forel, 1893g: 400 (q.m.). Subspecies of fallax: Forel, 1893g: 400. Raised to species: Emery, 1894g: 390. Subspecies of fallax: Emery, 1906c: 155; Forel, 1912f: 221. Raised to species, senior synonym of antillensis, arenicola, emiliae and material of the unavailable name retifera referred here: Wilson, 2003: 306.
 * arenicola. Pheidole jelskii var. arenicola Emery, 1894g: 390 (footnote) (s.w.) BRAZIL. Subspecies of fallax: Forel, 1908c: 370; Santschi, 1923d: 58. Junior synonym of jelskii: Wilson, 2003: 307.
 * antillensis. Pheidole jelskii var. antillensis Forel, 1901e: 356 (s.) ANTILLES. Subspecies of fallax: Bolton, 1995b: 317. Junior synonym of jelskii: Wilson, 2003: 307.
 * emiliae. Pheidole fallax r. emiliae Forel, 1901e: 352 (s.w.q.) BRAZIL. Junior synonym of jelskii: Wilson, 2003: 307.

See the extensive discussion by Wetterer et al. (2015) in the identification section of Pheidole obscurithorax

Description
From Wilson (2003): A member of the fallax group, similar to Pheidole fallax, Pheidole obscurithorax, Pheidole puttemansi, Pheidole roushae, Pheidole tobini and Pheidole valens, and especially the common and widespread fallax, with which it is easily confused.

Major: posterior half of dorsal surface of head completely carinulate; pronotum transversely carinulate; anterior fourth to third of central strip of first gastral tergite shagreened; head tapered toward occiput in side view, as depicted.

P. jelskii differs from P. fallax as follows and as shown: in major, petiole distinctly lower and descending to the peduncle by a much less concave curve, and scapes longer (Scape Length/Head Width 0.60–0.70 as opposed to 0.50–0.59 in fallax major); and in minor, occiput much narrower and nuchal collar thinner than in fallax.

MEASUREMENTS (mm) Holotype major: HW 1.48, HL 1.54, SL 1.00, EL 0.24, PW 0.80. Minor (Cuzco Amazónico, Madre de Dios, Peru): HW 0.56, HL 0.76, SL 1.00, EL 0.20, PW 0.42.

COLOR Major: body medium reddish brown, mandibles dark reddish brown.

Minor: body and most of appendages dark brown, often almost blackish brown, tarsi and mandibles light brown.



'''Figure. Upper: unique holotype, major. Lower: minor (Cuzco Amazónico, near Puerto Maldonado, Madre de Dios, Peru, associated with major compared with lectotype). Scale bars = 1 mm.'''

Type Material
Cayenne, French Guiana, collected by “M. Jelski”. - as reported in Wilson (2003)

Etymology
Named after the collector, M. Jelski. (Wilson 2003)

References based on Global Ant Biodiversity Informatics

 * Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
 * Buren W. F. 1982. Red imported fire ant now in Puerto Rico. Florida Entomologist 65: 188-189.
 * Cuezzo, F. 1998. Formicidae. Chapter 42 in Morrone J.J., and S. Coscaron (dirs) Biodiversidad de artropodos argentinos: una perspectiva biotaxonomica Ediciones Sur, La Plata. Pages 452-462.
 * Delsinne T., Y. Roisin, and M. Leponce. 2007. Spatial and temporal foraging overlaps in a Chacoan ground-foraging ant assemblage. Journal of Arid Environments 71: 2944.
 * Forel A. 1901. Variétés myrmécologiques. Annales de la Société Entomologique de Belgique 45: 334-382.
 * Forel A. 1907. Formiciden aus dem Naturhistorischen Museum in Hamburg. II. Teil. Neueingänge seit 1900. Mitt. Naturhist. Mus. Hambg. 24: 1-20.
 * Forel A. 1908. Catálogo systemático da collecção de formigas do Ceará. Boletim do Museu Rocha 1(1): 62-69.
 * Forel A. 1909. Ameisen aus Guatemala usw., Paraguay und Argentinien (Hym.). Deutsche Entomologische Zeitschrift 1909: 239-269.
 * Forel A. 1912. Formicides néotropiques. Part III. 3me sous-famille Myrmicinae (suite). Genres Cremastogaster et Pheidole. Mémoires de la Société Entomologique de Belgique. 19: 211-237.
 * Franco W., N. Ladino, J. H. C. Delabie, A. Dejean, J. Orivel, M. Fichaux, S. Groc, M. Leponce, and R. M. Feitosa. 2019. First checklist of the ants (Hymenoptera: Formicidae) of French Guiana. Zootaxa 4674(5): 509-543.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Kusnezov N. 1953. La fauna mirmecológica de Bolivia. Folia Universitaria. Cochabamba 6: 211-229.
 * LeBrun, E.G., M. Moffett and D.A. Holway. 2011. Convergent evolution of levee building behavior among distantly related ant species in a floodplain ant assemblage. Insectes Sociaux 58:263-269
 * Mann W. M. 1916. The Stanford Expedition to Brazil, 1911, John C. Branner, Director. The ants of Brazil. Bulletin of the Museum of Comparative Zoology 60: 399-490
 * Menozzi C, Russo G. 1930. Contributo alla conoscenza della mirmecofauna della Repubblica Dominicana (Antille). Bollettino del Laboratorio di Zoologia Generale e Agraria della Reale Scuola Superiore d'Agricoltura. Portici. 24: 148-173.
 * Morrison L. W. 1998. A review of Bahamian ant (Hymenoptera: Formicidae) biogeography. Journal of Biogeography 25: 561-571.
 * Perez-Gelabert D. E. 2008. Arthropods of Hispaniola (Dominican Republic and Haiti): A checklist and bibliography. Zootaxa 1831:1-530.
 * Radoszkowsky O. 1884. Fourmis de Cayenne Française. Trudy Russkago Entomologicheskago Obshchestva 18: 30-39.
 * Santschi F. 1923. Pheidole et quelques autres fourmis néotropiques. Annales de la Société Entomologique de Belgique 63: 45-69.
 * Smith M. R. 1937. The ants of Puerto Rico. Journal of Agriculture of the University of Puerto Rico 20: 819-875.
 * Smith M. R. 1942. The relationship of ants and other organisms to certain scale insects on coffee in Puerto Rico. Journal of Agriculture of the University of Puerto Rico 26: 21-27.
 * Weber N. A. 1938. New ants from stomachs of Bufo marinus L. and Typhlops reticulatus (L). Ann. Entomol. Soc. Am. 31: 207-210.
 * Weber N. A. 1938. The food of the giant toad, Bufo marinus (L.), in Trinidad and British Guiana with special reference to the ants. Annals of the Entomological Society of America 31: 499-503.
 * Wheeler W. M. 1905. The ants of the Bahamas, with a list of the known West Indian species. Bulletin of the American Museum of Natural History 21: 79-135.
 * Wheeler W. M. 1908. The ants of Porto Rico and the Virgin Islands. Bulletin of the American Museum of Natural History 24: 117-158.
 * Wheeler W. M. 1916. Ants collected in British Guiana by the expedition of the American Museum of Natural History during 1911. Bulletin of the American Museum of Natural History 35: 1-14.
 * Wheeler W. M. 1919. The ants of Tobago Island. Psyche (Cambridge) 26: 113.
 * Wheeler W. M. 1922. The ants of Trinidad. American Museum Novitates 45: 1-16.
 * Wheeler W. M., and W. M. Mann. 1914. The ants of Haiti. Bulletin of the American Museum of Natural History 33: 1-61.
 * Wheeler, William Morton. 1911. Ants Collected in Grenada, W.I. by Mr. C. T. Brues. Bulletin of the Museum of Comparitive Zoology at Harvard College. 54(5):166-172.
 * Wheeler, William Morton. 1936. Ants From Hispaniola and Mona Island. Bulletin: Museum of Comparative Zoology at Harvard College. 80(2):192-211.