Strumigenys milae

Strumigenys milae
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Strumigenys
Species:	S. milae
Binomial name
Strumigenys milae Fisher, 2000 Specimen labels

The type material was collected from disturbed montane rainforest leaf-litter.

Identification

Fisher (2000) - A member of the hilaris complex in the Strumigenys arnoldi-group. S. milae is most similar to Strumigenys luca in the hilaris-complex. They both have relatively short scapes (SI < 90). S. milae can be isolated from luca by the presence of two pairs of erect hairs on mesonotum, a shorter pair posterior to pair on anterior margin, the posterior portion of mesonotum sharply depressed behind the level of the anterior pair of hairs when viewed in profile. S. luca has a single pair of erect hairs on mesonotum. In addition, the petiole node of milae is evenly convex when viewed in profile while in luca, the petiole node is broadly triangular with a blunt apex. See Strumigenys hilaris for further discussion of the complex.

Keys including this Species

• Key to Malagasy Strumigenys

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -20.76805556° to -20.775°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

Malagasy Region: Madagascar (type locality).

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. ‎

Castes

Images from AntWeb

Holotype of Strumigenys milae. Worker. Specimen code casent0005604. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by MCZ, Cambridge, MA, USA.

Nomenclature

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

• milae. Strumigenys milae Fisher, in Bolton, 2000: 665 (w.) MADAGASCAR.

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

Description

Worker

Holotype. TL 3.2, HL 0.73, HW 0.60, CI 83, ML 0.42, MI 57, SL 0.50, SI 82, PW 0.36, AL 0.77. Characters of hilaris-complex. Each mandible with 2 preapical teeth, situated in the apical third; proximal preapical tooth longer than distal. Upper scrobe margin distinct, not bordered by a projecting laminar rim or flange throughout its length. Eyes moderate in size, convex and plainly visible in full-face view; maximum diameter of eye distinctly greater than maximum width of scape. Scape short, curved near base, widest in the midsection; hairs on leading edge fine, slightly flattened or spoon-shaped apically. Cephalic dorsum densely clothed with rows of curved narrow spatulate to spoon-shaped ground-pilosity; upper scrobe margin fringed with hairs which are the same size and shape as those on the dorsum. Cephalic dorsum with 4 stout standing hairs bordering occipital margin and a more anteriorly situated pair on vertex. Pronotal humeral hair absent; humeral angles rounded, posterolateral margin of pronotum bluntly marginate. Mesonotum with two pairs of stout filiform erect hairs; a pair on anterior margin and a shorter pair located posterior of mesonotal depression; one or two pairs of shorter hairs which curve toward the midline are present on anterior portion of mesonotum. Propodeum with one or two pairs of short, fine, posteriorly curved hairs at anterior base of propodeal spines or immediately anterior of propodeal spines. Ground-pilosity on alitrunk as on head, concentrated on the promesonotum. Dorsum of alitrunk in outline convex anteriorly, posterior mesonotum sharply depressed, posterior alitrunk more or less flat to gradually sloping to declivity. Propodeal spines narrowly triangular, spongiform, subtended by a narrow lamella on declivity. Alitrunk dorsum and sides of pronotum densely reticulate-punctate; pleurae smooth and shiny with peripheral punctures. Petiole node in dorsal view about as broad as long. Postpetiole reticulate-punctulate and with weak longitudinal striolate sculpture. In profile ventral spongiform tissue of petiolar peduncle an irregular, narrow strip along the base of the peduncle, its deepest point much less than maximum width of eye. Basigastral costulae short and distinct, with secondary and much longer superficial fine striolate sculpture arising between the shorter costulae. Dorsal surfaces of petiole, postpetiole and gaster with erect narrowly remiform hairs. Colour light to medium brown.

Paratypes. TL 2.9-3.1, HL 0.67-0.73, HW 0.54-0.58, CI 79-81, ML 0.38-0.41, MI 54-57, SL 0.46-0.48, SI 82-86, PW 0.33-0.37, AL 0.73-0.79 (3 measured). As holotype.

Measurements of this material extend the range shown by the type-series: HL 0.71, HW 0.59, CI 83, ML 0.41, MI 59, SL 0.47, SI 81 (1 measured) but otherwise match diagnostic characters of the type-specimens.

Type Material

Holotype worker, Madagascar: Provo Fianarantsoa, 28 km. SSW Ambositra, Ankazomivady, 20°46.5'S, 47°10.1'E, 1670 m., l4.i.1998, sifted litter (leaf mold, rotten wood), disturbed montane rainforest #1625-4 (B. L. Fisher) (Museum of Comparative Zoology).

Paratypes. 1 worker with same data as holotype; 2 workers with same data as holotype but 11.i.1998, #1620 (2)-2, #1620 (5)-1 (The Natural History Museum, South African Museum).

References

• Fisher, B.L. 2000. The Malagasy fauna of Strumigenys. Pp. 612-696 in: Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 665, worker described)

References based on Global Ant Biodiversity Informatics

• Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
• Fisher B. L. 2003. Formicidae, ants. Pp. 811-819 in: Goodman, S. M.; Benstead, J. P. (eds.) 2003. The natural history of Madagascar. Chicago: University of Chicago Press, xxi + 1709 pp.