Strumigenys benten

Every Ant Tells a Story - And Scientists Explain Their Stories Here
Jump to navigation Jump to search
Strumigenys benten
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. benten
Binomial name
Strumigenys benten
(Terayama, Lin & Wu, W.-J., 1996)

Pyramica benten side (

Pyramica benten top (

Specimen labels

Distributed in south-western Japan, nesting in the soil or under stones and sampled in Berlese funnel forest-litter samples. A colony collection (Takatsuki, Osaka Prefecture) was found under a concrete stone among thinly spaced trees on the precints of a temple. It included more than 150 workers. (Ogata and Onoyama 1998)


Bolton (2000) - A member of the Strumigenys leptothrix-group. This species is very closely related to Strumigenys alecto but has the differences tabulated below. The two may eventually prove to be extreme variants of a single species (Ogata & Onoyama, 1998). Strumigenys formosimonticola may also be involved in the variation as Touyama (1998) has documented some interesting pilosity variants that he includes under benten. Until more material is available I regard the following features as being diagnostic of two separate but sibling species, because the distribution and density of specialised pilosity is usually fairly stable in Pyramica species.

S. alecto: With head in profile the dorsum with short erect simple hairs at, in front of and behind the highest point of the vertex. With the head in occipital view 20 or more short erect hairs visible on dorsum. Dorsal (outer) surfaces of middle and hind tibiae with numerous short straight projecting simple suberect hairs. Pronotal dorsum with short erect hairs present anteriorly other than those at the humeri. Pronotal dorsum finely reticulate-punctate.

S. benten: With head in profile the dorsum with short erect hairs only behind highest point of the vertex. With the head in occipital view no more than 8-10 short erect hairs visible on dorsum. Dorsal (outer) surfaces of middle and hind tibiae with apically directed appressed hairs only. Pronotal dorsum without erect hairs except at the humeri. Pronotal dorsum not reticulate-punctate.

Keys including this Species


Distribution based on Regional Taxon Lists

Oriental Region: Taiwan (type locality).
Palaearctic Region: Japan.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


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.



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

  • benten. Smithistruma benten Terayama, Lin & Wu, 1996: 329, figs. 1-5, 20 (w.q.) TAIWAN. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 116. See also: Bolton, 2000: 431.

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



Bolton (2000) - TL 2.1- 2.6, HL 0.60-0.65, HW 0.44-0.50, CI 71-82, ML 0.13-0.17, MI 13-15 [measurement in Terayama, Lin & Wu (1996: 330) of MI 21-28, is too high; from specimens examined and their fig. 1, MI should be as above], SL 0.26-0.32, SI 59, PW 0.26-0.33, AL 0.65-0.72. Terayama, Lin, & Wu, (1996: 330) give a total dental count of 12 for benten but a specimen with mandibles ajar that I have examined had 14.]

Type Material

Bolton (2000) - Holotype worker and paratype workers and queens, TAIWAN: Nantou Hsien, Lienhuachih, 12.xi.1992 (C.-C. Lin). Paratype workers and queens, TAIWAN: Nantou Hsien, Taping-Meitzulin, ca 510 m., 30.vii.1988 (M. Terayama). JAPAN: Okinawa Pref., Ryukyu Is, Iriomote-jima I., 30.iii.1991 (M. Terayama); Mie Pref., Yokkaichi-shi, 21.iv.1987 (A. Amagasu); Mie Pref., Komono-machi, xii.1989 (M. Terayama); Komaba, Meguro-ku, Tokyo, (M. Terayama); Tokyo, Nakano-ku, 19.viii.1980 (S. Kubota) (National Institute of Agro-Environmental Sciences, National Science Museum (Natural History), National Taiwan University, Taiwan Agricultural Research Institute) [NSMT paratypes examined].