Strumigenys dipsas

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

Nothing is known about the biology of Strumigenys dipsas.

Identification

Bolton (2000) - A member of the caniophanes complex in the Strumigenys caniophanes-group. Within the group six species, Strumigenys benulia, Strumigenys daithma, dipsas, Strumigenys lacunosa, Strumigenys paraposta and Strumigenys pliocera have the following four characters in combination.

1 Inner margin of mandible without a cuticular lamella.

2 Preapical tooth or denticle present on mandible.

3 Dorsal (outer) surfaces of middle and hind tibiae and basi tarsi with freely projecting long hairs.

4 Katepisternum not completely sculptured, with at least a smooth shining area and sometimes entirely smooth.

Four of these species (benulia, daithma, lacunosa, paraposta) have the hind femur bearing a conspicuous row of fine suberect to erect hairs on its dorsal surface. Of these lacunosa has the lateral spongiform lobe of the petiole large. In dorsal view the lateral lobes project strongly on each side of the node, broadest posteriorly and narrowing anteriorly, extending as far forward as the anteriormost point of the node. In the other three species the lobes are much more restricted and do not approach the anterior end of the node. S. paraposta has transverse costulate sculpture on the front coxae and sculptured metapleuron and side of propodeum, both of which are absent in the last two species, benulia and diathma. These two are easily separated by the very different sculpture of their dorsal alitrunks and the other characters given in the key.

The other two species lack a row of erect hairs on the dorsal surface of the hind femur. Of these pliocera has its pronotum punctate dorsally, and has 3 long hairs projecting laterally from the upper scrobe margin, the posteriormost of which is the apicoscrobal hair. S. dipsas on the other hand has its pronotum longitudinally rugulose dorsally, and has only the apicoscrobal hair on the upper scrobe margin.

Keys including this Species

Key to Strumigenys of East Asia

Distribution

Distribution based on Regional Taxon Lists

Oriental Region: Thailand (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.

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Castes

Nomenclature

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

dipsas. Strumigenys dipsas Bolton, 2000: 757 (w.q.) THAILAND.

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 3.0, HL 0.80, HW 0.57, CI 71, ML 0.37, MI 46, SL 0.42, SI 74, PW 0.34, AL 0.87. Mandible with a small preapical tooth. Apicoscrobal hair present; without laterally projecting hairs on upper scrobe margin anterior to this. Cephalic dorsum with a pair of erect fine hairs that straddle the midline close to the occipital margin; usually also with a shorter erect hair on lateral margin of occipital lobe but without erect hairs at highest point of vertex. Dorsum of head densely reticulate-rugulose, tops of rugulae and spaces between rugular meshes finely punctulate. Promesonotal dorsum rugulose, predominantly longitudinally so; similar sculpture present on propodeal dorsum but much weaker, finer and less conspicuous. Side of pronotum longitudinally rugulose; katepisternum smooth; metapleuron with some punctate sculpture anteriorly but most of its surface, and that of side of propodeum, longitudinally rugulose. Anterior coxae with weak transverse rugulae. Pronotal humeral hair long and fine, flagellate or looped apically (apparently fragile, broken off at about its midlength in half the paratypes). Pronotal dorsum with 1-2 pairs of erect fine hairs, mesonotum with 3-4 similar pairs. First gastral tergite with long fine filiform to flagellate hairs. Dorsal surface of hind femur without standing hairs, but 1-2 may be present on ventral surface; dorsal (outer) surfaces of hind tibia and basitarsus each with 1-2 long erect freely projecting filiform or flagellate hairs. Propodeal teeth short, triangular and acute. Petiole in profile claviform.

Paratypes. TL 3.0-3.2, HL 0.80-0.86, HW 0.57-0.60, CI 69-73, ML 0.37-0.40, MI 45-49, SL 0.42-0.44, SI 73-76, PW 0.30-0.35, AL 0.87-0.90 (5 measured).

Type Material

Holotype worker, Thailand: Doi Inthanon, 7.xi.1985, no. 15 (Lobl & Burckhardt) (Musee d'Histoire Naturelle Genève).

Paratypes. 10 workers and 4 queens with same data as holotype; 6 workers with same data but no. 14; 4 workers and 1 queen with same data but 1650 m., no. 16 (MHNG, The Natural History Museum, Museum of Comparative Zoology).

References

Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 757, worker described)
Khachonpisitsak, S., Yamane, S., Sriwichai, P., Jaitrong, W. 2020. An updated checklist of the ants of Thailand (Hymenoptera, Formicidae). ZooKeys 998, 1–182 (doi:10.3897/zookeys.998.54902).
Tang, K. L., Guénard, B. 2023. Further additions to the knowledge of Strumigenys (Formicidae: Myrmicinae) within South East Asia, with the descriptions of 20 new species. European Journal of Taxonomy 907, 1–144 (doi:10.5852/ejt.2023.907.2327).

References based on Global Ant Biodiversity Informatics

Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65