Strumigenys irrorata

Strumigenys irrorata
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Strumigenys
Species:	S. irrorata
Binomial name
	Strumigenys irrorata; Santschi, 1913 Specimen Labels

The few collections of this species have each been from a different habitat. All the specimens have been obtained from litter samples.

Identification

Bolton (1983, 2000) - A member of the dextra complex in the Strumigenys arnoldi-group. S. irrorata has a single preapical tooth on each mandibular blade.

Keys including this Species

Key to Afrotropical Strumigenys

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -25.15216° to -28.66667°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Afrotropical Region: South Africa (type locality), Zimbabwe, Zimbabwe.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Explore Overview of Strumigenys biology

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.

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Castes

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

irrorata. Strumigenys (Strumigenys) irrorata Santschi, 1913b: 257 (diagnosis in key) (w.) SOUTH AFRICA. Santschi, 1914e: 29 (w.). See also: Brown, 1954k: 33; Bolton, 1983: 375; Bolton, 2000: 593.

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

Description

Worker

Bolton (1983) - TL 1.9-2.1, HL 0.47-0.54, HW 0.38-0.43, CI 76-83, ML 0.19-0.23, MI 40-43, SL 0.24-0.28, SI 62-70, PW 0.24-0.27, AL 0.50-0.56 (10 measured).

Apical fork of each mandibular blade with 2 spiniform teeth, without intercalary teeth or denticles. Pre apical armament of a single spiniform tooth on each blade which corresponds to the proximal preapical tooth in related species; the distal preapical teeth lost. Upper scrobe margins strongly divergent behind the frontal lobes, the eyes not visible in full-face view. Eyes very small, conspicuously much smaller than the maximum width of the scape. Preocular notch absent, the ventral surface of the head without a preocular transverse groove or impression. Scapes short, weakly curved, their anterior margins shallowly convex and equipped with a row of short spoon-shaped to scale-like hairs. Ground-pilosity of cephalic dorsum of dense short spoon-shaped hairs which are broad and appear scale-like in full-face view. Hairs fringing the upper scrobe margins the same as those on the dorsum, and about equal in size to the projecting hairs on the leading edges of the scapes. Dorsum of head with 6 standing hairs, arranged in a transverse row of 4 close to the occipital margin and a more anteriorly situated pair. Dorsum of head densely reticulate-punctate. Pronotal humeri each with a single long fine flagellate hair. Mesonotum with a single pair of stout standing hairs which are weakly clavate apically. Ground-pilosity of dorsal alitrunk of sparse small hairs which are spatulate to narrowly spoon-shaped. Propodeal teeth subtended by broad infradental lamellae. Metanotal groove not impressed. Sides of alitrunk mostly smooth, sometimes with vague traces of sculpture on the pronotal sides and usually with weak punctulae on the pleurae and propodeum. Pronotal dorsum longitudinally rugulose, the rest of the dorsal alitrunk punctate. Dorsum of petiole node punctate, the postpetiole smooth and shining. Spongiform appendages of pedicel segments well developed, the petiole with a broad ventral spongiform strip and the postpetiole with large ventral and lateral lobes. Basigastral costulae short but sharply defined. Dorsal surfaces of petiole, postpetiole and gaster with stout standing hairs which are weakly clavate apically. Colour medium to dark brown.

Type Material

Bolton (1983) - Holotype worker, SOUTH AFRICA: Natal, Zululand, Lake Sibayi (I. Triigardh) (Naturhistorisches Museum, Basel) [examined].

References

Arnold, G. 1917. A monograph of the Formicidae of South Africa. Part III. Myrmicinae. Ann. S. Afr. Mus. 14: 271-402 (page 375, redescription of worker)
Bolton, B. 1983. The Afrotropical dacetine ants (Formicidae). Bulletin of the British Museum (Natural History). Entomology. 46:267-416. (page 375, redescription of worker)
Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 593, redescription of worker)
Santschi, F. 1913b. Clé analytique des fourmis africaines du genre Strumigenys Sm. (Hym.). Bull. Soc. Entomol. Fr. 1913: 257-259 (page 257, worker described)
Santschi, F. 1914e. Meddelanden från Göteborgs Musei Zoologiska Afdelning. 3. Fourmis du Natal et du Zoulouland récoltées par le Dr. I. Trägårdh. Göteb. K. Vetensk. Vitterh. Samh. Handl. 15: 1-44 (page 29, description of worker)

References based on Global Ant Biodiversity Informatics

Arnold G. 1917. A monograph of the Formicidae of South Africa. Part III. Myrmicinae. Annals of the South African Museum. 14: 271-402.
Bolton B. 1983. The Afrotropical dacetine ants (Formicidae). Bulletin of the British Museum (Natural History). Entomology 46: 267-416.
Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
Santschi F. 1913. Clé analytique des fourmis africaines du genre Strumigenys Sm. (Hym.). Bulletin de la Société Entomologique de France 1913: 257-259.
Santschi F. 1914. Meddelanden från Göteborgs Musei Zoologiska Afdelning. 3. Fourmis du Natal et du Zoulouland récoltées par le Dr. I. Trägårdh. Göteborgs Kungliga Vetenskaps och Vitterhets Samhälles Handlingar. 15: 1-44.
Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bulletin of the American Museum of Natural History 45: 711-1004