Cataulacus wasmanni

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Cataulacus wasmanni
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. wasmanni
Binomial name
Cataulacus wasmanni
Forel, 1897

Cataulacus wasmanni casent0101998 profile 1.jpg

Cataulacus wasmanni casent0101998 dorsal 1.jpg

Specimen labels

Found in forested habitats, little is known about the biology of Cataulacus wasmanni.

Identification

A member of the huberi group. The description by Forel of the sculpturation and form of the alitrunk seems to ally Cataulacus wasmanni to Cataulacus oberthueri and its allies, particularly to Cataulacus regularis. It should be easily recognizable as it is the only Madagascan species on record in which the direction of sculpturation differs on the propodeum from that on the mesonotum. This arrangement of sculpture is known from two species of the Ethiopian region, namely Cataulacus inermis and Cataulacus pilosus, but in the first of these the propodeum lacks spines, whilst the second is densely hairy. (Bolton 1974)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Malagasy Region: Madagascar (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Nest chamber of Cataulacus wasmanni inside a living branch, showing adults and brood. From Makirovana, Madagascar. Photo by Christian Peeters.

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

Worker

Queen

Male

Nomenclature

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

  • wasmanni. Cataulacus (Otomyrmex) wasmanni Forel, 1897c: 193 (w.) MADAGASCAR. [Otomyrmex wasmanni Wasmann, 1897: 250. Nomen nudum, attributed to Forel.] See also: Bolton, 1974a: 29.

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 5.3.

Bolton 1974 fig 25-27

Occipital crest developed. Occipital corners with short, fairly small, triangular, ear-shaped points. Eyes very large, fiat. Sides of head behind eyes apparently not denticulate. Preocular tooth present. In profile the dorsal outline of the alitrunk hemispherically arched. Pronotum marginate, not denticulate, the margin sharp, horizontal and leaf-like. Mesonotum and propodeum with a horizontal, broad, short thorn or strong tooth. Promesonotal suture indicated by an impression. Propodeum with a pair of very long, acute, divergent spines, which are half as long as the entire alitrunk. Gaster short, elliptical, almost round in dorsal view.

Head densely and coarsely, regularly longitudinally rugose dorsally. Occipital surface behind the crest transversely rugose. Pronotum coarsely, densely longitudinally striate; the mesonotum similarly but very regularly striate. Propodeal dorsum transversely striate, the sides longitudinally so; similarly the segments of the pedicel. Gaster reticulate-punctate with fine but not dense longitudinal striation. Hairs absent from the dorsal surfaces of the head and body, present on the appendages, the anterior portion of the head and mandibles, and the gastral apex.

Type Material

Bolton (1974) - Holotype worker, MADAGASCAR: Isle Ste. Marie, Kalalo (location of type not known). I have not been able to locate the type of this species.

References