Strumigenys silvestrii

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Strumigenys silvestrii
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. silvestrii
Binomial name
Strumigenys silvestrii
Emery, 1906

Strumigenys silvestrii casent0005677 profile 1.jpg

Strumigenys silvestrii casent0005677 dorsal 1.jpg

Specimen labels

Synonyms

A South American species that has spread to other areas of the Neotropics. Strumigenys silvestrii likely has similar food habits as the three highly successful Old World tramp dacetine ants, Strumigenys membranifera, Strumigenys emmae, and Strumigenys rogeri, preying on tiny soil arthropods, such as Collembola (Wetterer, 2011, 2012a, b). The ecological importance of these dacetine invaders, however, remains largely unstudied.

Identification

Bolton (2000) - A member of the Strumigenys silvestrii-group. Within the silvestrii-group 6 species have pilosity on the first gastral tergite that is not predominantly or entirely of fine elongate or flagellate hairs. In these 6 the pilosity of the first gastral tergite is of spatulate, remiform or simple stiff hairs. One such species, Strumigenys ascita, has two narrowly spiniform preapical teeth on each mandible, as opposed to one tooth and a minute denticle in the remainder. Three species of Central American origin (Strumigenys calamita, Strumigenys perdita, Strumigenys nastata) retain spongiform tissue on the ventral surface of the petiole and have two pairs of short erect hairs on the cephalic dorsum. In the last two species, Strumigenys epelys and silvestrii, the petiole lacks spongiform tissue ventrally and the cephalic dorsum bears only a single pair of short erect hairs. Of these two species epelys lacks the projecting hairs on the head and alitrunk that are listed above for silvestrii. Finally, silvestrii is the only species of the 6 to have its distal preapical tooth set very close to the apicodorsal tooth.

Keys including this Species

Distribution

Apparently from South America and subsequently spread to the southern US and the West Indies. Strumigenys silvestrii has recently been found for the first time in the Old World, from the island of Madeira, mainland Portugal, and Macau. (MacGown et al. 2012)

Distribution based on Regional Taxon Lists

Nearctic Region: United States.
Neotropical Region: Argentina (type locality), Bahamas, Brazil, Cuba, Dominican Republic, Greater Antilles, Grenada, Paraguay.
Palaearctic Region: China, Iberian Peninsula, Portugal.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb MacGown sylvestrii map.jpg

Biology

Not much is known about the biology of this species. In general, (for species in this genus) Strumigenys were once thought to be rare. The development and increased use of litter sampling methods has led to the discovery of a tremendous diversity of species. Many species are specialized predators (e.g. see Strumigenys membranifera and Strumigenys louisianae). Collembola (springtails) and other tiny soil arthropods are typically favored prey. Species with long linear mandibles employ trap-jaws to sieze their stalked prey (see Dacetine trap-jaws). Larvae feed directly on insect prey brought to them by workers. Trophallaxis is rarely practiced. Most species live in the soil, leaf litter, decaying wood or opportunistically move into inhabitable cavities on or under the soil. Colonies are small, typically less than 100 individuals but in some species many hundreds. Moist warm habitats and micro-habitats are preferred. A few better known tramp and otherwise widely ranging species tolerate drier conditions. Foraging is often in the leaf litter and humus. Workers of many species rarely venture above ground or into exposed, open areas. Individuals are typically small, slow moving and cryptic in coloration. When disturbed individuals freeze and remain motionless. Males are not known for a large majority of species.

Regional Notes

Florida (USA)

Deyrup et al. (2000) - A rare but widely distributed species, known from a few sites from the keys north to Gadsden County. Found in leaf litter in woods. Members of this genus feed on small organisms, especially Collembola. First published Florida record: Johnson 1986; earlier specimens: 1984.

Castes

Worker

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • silvestrii. Strumigenys silvestrii Emery, 1906c: 168, fig. 27 (w.q.) ARGENTINA. Senior synonym of caribbea: Brown, 1959f: 25. See also: Bolton, 2000: 559.
  • caribbea. Strumigenys (Strumigenys) caribbea Weber, 1934a: 43, fig. 12 (w.q.) CUBA. Junior synonym of silvestrii: Brown, 1959f: 25.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Bolton (2000) - TL 1.6 - 2.0, HL 0.42 - 0.49, HW 0.33 - 0.37, CI 76 - 80, ML 0.22 - 0.26, MI 50 - 57, SL 0.24 - 0.31, SI 76 - 86, PW 0.21 - 0.25, AL 0.38 - 0.48 (6 measured). Apical fork of mandible usually with a minute intercalary denticle, may be very difficult to see; absent in some. Mandible with preapical tooth located very close to apicodorsal tooth; the two almost adjacent and the length of the preapical tooth greater than the distance between it and the apicodorsal. A minute denticle also present on inner margin of mandible, often difficult to see, located close to midlength. Ground-pilosity of head and leading edge of scape fine and slender, narrowly spatulate. Specialised projecting hairs on head and alitrunk stiff, feebly remiform or somewhat flattened apically: in apicoscrobal position; a short pair on cephalic dorsum close to occipital margin; at pronotal humerus; a pair on mesonotum. All hairs on first gastral tergite narrowly remiform and elevated, inclined toward midline in dorsal view, in profile appearing curved or inclined posteriorly. Petiole node in dorsal view slightly broader than long; ventral surface of petiole without spongiform tissue and lateral spongiform lobe vestigial to absent, at most nothing more than a slight expansion at apex of the posterior collar. Disc of postpetiole mostly or entirely smooth, at most with some faint superficial vestiges of sculpture.

Type Material

Bolton (2000):

Syntype workers and queen, ARGENTINA: Santa Catalina, Buenos Aires (F. Silvestri) (Museo Civico di Storia Naturale, Genoa, Naturhistorisches Museum Wien, Vienna) [examined].

Strumigenys (Strumigenys) caribbea Weber, 1934a: 43, fig. 12. Syntype workers and queens, CUBA: Soledad, Cienfuegos, 15.viii.1933 (queens) (N.A. Weber); Soledad, Cienfuegos, 4.xi.1927 (workers) (W.S. Creighton) (National Museum of Natural History , Museum of Comparative Zoology, The Natural History Museum) [examined].

References