Strumigenys diasphax

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

The type material was collected from a mixed dipterocarp forest and at the edge of a primary montane forest.

Identification

Bolton (2000) - A member of the Strumigenys wallacei-group. Easily identified as this is the only species in the group to have standing hairs on the dorsolateral and occipital margins of the head and 4 pairs of erect stout hairs on the promesonotum. S. diasphax is smaller and more gracile than the other two species in the group and has a narrower head, CI 76-82 as opposed to CI 86-96 in Strumigenys gnathosphax and Strumigenys wallacei together.

Keys including this Species

Key to Strumigenys of East Asia

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo (type locality), Indonesia, Malaysia.

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.

diasphax. Strumigenys diasphax Bolton, 2000: 910 (w.) BORNEO.

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 2.3, HL 0.66, HW 0.54, CI 82, ML 0.36, MI 55, SL 0.44, SI 81, PW 0.29, AL 0.66. Apical fork of mandible with a minute intercalary denticle, inconspicuous and may be reduced to a tubercle (may be lost in some specimens). Scrobe in profile absent behind level of eye. Propodeum with short spines, declivity with a weakly spongiform lobe ventrally, the two connected by a weak carina. Ventral spongiform curtain of petiole at deepest distinctly greater than half the depth of the peduncle. Dorsal surface of head with narrowly spatulate ground-pilosity and 4 - 6 stout standing hairs along occipital margin. Appressed anteriorly curved hairs that fringe upper scrobe margin to level of eye minute, much smaller than hairs on leading edge of scape. Dorsolateral margin behind level of eye with 3-4 stiff stout projecting hairs that are directed more dorsally than laterally and are larger than the hairs on the leading edge of the scape. Pronotal humeral hair long, stout and stiff; dorsum of pronotum with a pair of standing hairs. Mesonotum with 3 pairs of erect stiff hairs that are expanded apically or remiform. Waist segments and first gastral tergite with stout stiff hairs that are simple or somewhat expanded apically, those on gaster suberect to erect. Mesopleuron mostly smooth but metapleuron and side of propodeum weakly reticulate-punctate, as is disc of postpetiole.

Paratypes. TL 2.2-2.3, HL 0.66-0.69, HW 0.52-0.55, CI 76-82, ML 0.36-0.38, MI 53-58, SL 0.40-0.44, SI 78-85, PW 0.28-0.30, AL 0.64-0.66 (7 measured).

Type Material

Holotype worker, Malaysia: Sarawak, 4th Div., Gn. Mulu N. P., v.-viii.1978, BM 1978-49, mixed dipterocarp forest (Hammond & Marshall) (The Natural History Museum). Paratypes. 12 workers, Malaysia: Sarawak, Gn. Penrissen, 1000 m., 23.v.1994, edge prim. montane for., #9a (Lobl & Burckhardt) (Musee d'Histoire Naturelle Genève, BMNH, Museum of Comparative Zoology).

References

Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 910, worker described)
Musfira, S.H., Rafi, M., Gusti, M., Putri, D.H., Satria, R. 2022. New data on the genus Strumigenys (Hymenoptera: Formicidae) from Sumatra. Zoosystematica Rossica 31(1): 74–86 (doi:10.31610/zsr/2022.31.1.74).
Satria, R., Herwina, H. 2020. New distribution record of ants species (Hymenoptera: Formicidae) to the fauna of Sumatra island, Indonesia. International Conference on Biology, Sciences and Education (ICoBioSE 2019). Advances in Biological Sciences Research, 10: 82–84. Atlantis Press (doi:10.2991/absr.k.200807.020).

References based on Global Ant Biodiversity Informatics

Hashimoto Y., Y. Morimoto, and M. Mohamed. 2002. Species list of ground and leaf litter ants collected in Lower Kinabatangan. Lower Kinabatangan : scientific expedition 2002/ 13-18.
Hashimoto Y., Y. Morimoto, and M. Mohamed. 2003. Species List of Ground and Leaf Litter Ants Collected in Lower Kinabatangan. Pp 13-18. In Lower Kinabatangan Scientific Expedition 2002, 176 pp. ISBN-13: 983-2369-11-8
Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58