Cataulacus weissi

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Cataulacus weissi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. weissi
Binomial name
Cataulacus weissi
Santschi, 1913

Cataulacus weissi P casent0280806.jpg

Cataulacus weissi D casent0280806.jpg

Specimen Label

Synonyms

Cataulacus weissi appears to be restricted to rather densely wooded or forested areas. The female and male were first described by Forel (1916:427) from the myrmecophilous plant Randia myrmecophila de Wilde. (Bolton 1974)

Identification

A member of the tenuis group. This small species, although of the tenuis-group, resembles Cataulacus pygmaeus, from which it is separated by the form of the subpetiolar process, the consistently larger ocular index and the form of sculpture upon the petiole.

Keys including this Species

Distribution

Known from Congo and Ghana.

Distribution based on Regional Taxon Lists

Afrotropical Region: Congo (type locality), Ghana, Ivory Coast.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Much of the information concerning the biology of Cataulacus species is anecdotal and fragmentary. Arnold (1917) wrote a succinct general overview of Cataulacus biology that still remains quite informative. Arnold reports "all the species of this genus are tree-ants, usually forming medium sized nests in hollow twigs and stems, or more rarely, under the bark. They are timid and slow-moving insects, often feigning death or dropping rapidly to the ground when disturbed. As Bingham has remarked in connection with this genus (Fauna Brit. India, Formicidae), these ants have the habit of wandering over the trunks of trees and the leaves in what appears to be a very aimless and languid manner. I have occasionally seen them breaking open the earthen tunnels constructed by termites over the trunks of trees and attack the inmates."

Bolton (1974) expands upon this earlier account - "All known Cataulacus species are arboreal or subarboreal nesters and they predominantly forage on the trees and shrubs in which the nests are situated. Very few appear to come down to ground level but in West Africa the small species Cataulacus pygmaeus and Cataulacus brevisetosus may be found foraging in leaf litter or crossing the ground to ascend a tree other than the one in which the nest is situated. The nests themselves are usually constructed in small hollow twigs or stems by the smaller species and in rotten branches or rotted portions of the tree trunk by the larger species. This is rather a generalization as some small species are known which nest in and under rotten bark (e.g. Cataulacus vorticus) and undoubtedly some of the larger forms will eventually be found inhabiting relatively small cavities in plants.

Various species of the genus in Africa are known to inhabit a variety of galls, acacias and bushes as well as large trees. Numerous species have been found nesting in, and have therefore been often collected from, cocoa in Africa. Some of these species are Cataulacus guineensis, Cataulacus pygmaeus, Cataulacus mocquerysi, Cataulacus egenus, Cataulacus vorticus, Cataulacus brevisetosus, Cataulacus kohli and Cataulacus theobromicola. Feeding habits in the genus are mostly unknown but the present author has noted C. guineensis tending aphids and small coccids.

On the plants ants of the genus Cataulacus often occur together with Oecophylla or species of Crematogaster, and appear to be mostly tolerated (at least they are not evicted) by the majority of these forms. Their defence against attackers of these genera lies primarily in their armoured exterior, but their ultimate escape reaction is to curl up and release their grip on the plant, falling to the ground and thus making their escape. The decision to remain immobile and present an armoured surface or to drop from the plant appears to depend upon the size or persistence of the aggressor; larger attackers usually precipitate the latter reaction, but it has also been noted as a result of persistent and unwanted attention by a series of workers of a small Crematogaster species.

The majority of species are forest-dwelling forms, with relatively few adapted to savannah or veldt conditions. Those which do, however, occur in these zones tend to be very successful in their chosen habitat and often possess a wide distribution. A few species are apparently able to exist in any region of Africa providing the basic essentials of nesting-site and food supply are met with, but on the whole the fauna may be divided into forest and non-forest forms."

Some species have nests that can be protected by a single worker's head, as its shape matches the nest entrance and forms an effective plug.

It has more recently been discovered that some species of Cataulacus are efficient gliders (Cataulacus erinaceus, Cataulacus guineensis, Cataulacus mocquerysi and Cataulacus tardus). Workers exhibit directed movement while in freefall that allows them to glide back to regain a hold on the same tree trunk. (Yanoviak et al. 2005, 2007, 2008)

Castes

Nomenclature

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

  • weissi. Cataulacus weissi Santschi, 1913c: 310 (w.) CONGO. Forel, 1916: 427 (q.m.). Subspecies of pygmaeus: Santschi, 1916b: 506; of lujae: Santschi, 1924b: 219. Revived status as species: Bolton, 1974a: 39. Senior synonym of plectroniae: Bolton, 1974a: 39; of aethiops: Bolton, 1982: 358.
  • plectroniae. Cataulacus traegaordhi var. plectroniae Wheeler, W.M. 1922a: 199 (w.) DEMOCRATIC REPUBLIC OF CONGO. Junior synonym of weissi: Bolton, 1974a: 39.
  • aethiops. Cataulacus jeanneli var. aethiops Santschi, 1924b: 220 (w.) DEMOCRATIC REPUBLIC OF CONGO. Junior synonym of weissi: Bolton, 1982: 358.

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

Description

Worker

Bolton (1974) - TL 3.3 – 3.6, HL 0.82 – 0.96, HW 0.74 – 0.86, CI 89 - 95, EL 0.40 – 0.46, OI 51 - 54, IOD 0.58 – 0.64, SL 0.40 – 0.50, SI 51 - 58, PW 0.60 – 0.70, AL 0.90 – 1.00, MTL 0.44 – 0.48 (5 measured).

Occipital crest absent, the two surfaces meeting through a continuous convexity. Occipital corners with a small tooth and with a second such upon the occipital margin close to them. Sides of head behind eyes denticulate. Pronotum marginate laterally, serially denticulate; the margins of the mesonotum and propodeum also with one or more denticles. Propodeum with a pair of short, acute spines. Dorsal ali trunk without sutures. Subpetiolar process complex, the posteroventral angle drawn out into a long heel or spur. Subpostpetiolar process well developed, digitiform, almost as long as the subpetiolar process. First gastral tergite not marginate laterally. Dorsum of head and alitrunk with a fine loose rugoreticulum, the interspaces reticulate-punctate, more strongly so upon the alitrunk than upon the head. Petiole in dorsal view finely and regularly rugose, the rugae U- or V-shaped. First gastral tergite densely reticulate-punctate.

Simple stout, blunt hairs numerous everywhere, very conspicuous.

Queen

Bolton (1974) - TL 4.1, HL 0.94, HW 0.84, CI 90, EL 0.42, OI 50, IOD 0.64, SL 0.46, SI 55, PW 0.74, AL 1.20, MTL not measurable.

As worker but with the denticulation of the sides of the head behind the eyes reduced, and also that of the pronotal margins. Propodeal spines short and blunt. Subpetiolar process with the posteroventral angle not as strongly developed as in worker, but still prominent. Sculpturation similar to that of worker but the mesoscutum and scutellum distinctly and quite closely longitudinally rugose.

Type Material

Bolton (1974):

Holotype worker, CONGO: Brazzaville, 1907 (A. Weiss) (NM, Basle) [examined].

Cataulacus traegaordhi var. plectroniae Syntype workers, ZAIRE: Stanleyville, from cavities of Plectronia sp. (Lang &- Chapin) (MCZ, Boston).

Cataulacus jeanneli st. kenyensis Syntype workers, KENYA: Nairobi, st. 2, 1660 m, 1932-33 (C. Arambourg, P. A. Chappuis &- R. Jeannel) (NM, Basle) [examined].

References

  • Bolton, B. 1974a. A revision of the Palaeotropical arboreal ant genus Cataulacus F. Smith (Hymenoptera: Formicidae). Bull. Br. Mus. (Nat. Hist.) Entomol. 30:1-105. PDF (page 39, Revived status as species, and senior synonym of plectroniae)
  • Bolton, B. 1982. Afrotropical species of the myrmecine ant genera Cardiocondyla, Leptothorax, Melissotarsus, Messor and Cataulacus (Formicidae). Bulletin of the British Museum (Natural History). Entomology, 46: 307-370 (page 358, Senior synonym of aethiops)
  • Forel, A. 1916. Fourmis du Congo et d'autres provenances récoltées par MM. Hermann Kohl, Luja, Mayné, etc. Rev. Suisse Zool. 24: 397-460 (page 427, queen, male described)
  • Santschi, F. 1913c. Glanures de fourmis africaines. Ann. Soc. Entomol. Belg. 57: 302-314 (page 310, worker described)
  • Santschi, F. 1916b [1915]. Descriptions de fourmis nouvelles d'Afrique et d'Amérique. Ann. Soc. Entomol. Fr. 84: 497-513 (page 506, Stirps of pygmaeus)
  • Santschi, F. 1924b. Descriptions de nouveaux Formicides africains et notes diverses. II. Rev. Zool. Afr. (Bruss.) 12: 195-224 (page 219, Variety of lujae)