Cataulacus moloch

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Cataulacus moloch
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. moloch
Binomial name
Cataulacus moloch
Bolton, 1982

Cataulacus moloch casent0900270 p 1 high.jpg

Cataulacus moloch casent0900270 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Cataulacus moloch.

Identification

A member of the tenuis group. C. moloch is closest related to Cataulacus centrurus, the differences between them are noted under the latter name. (Bolton 1982)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Ghana (type locality), Kenya, Nigeria.

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.

  • moloch. Cataulacus moloch Bolton, 1982: 361, fig. 34 (w.) GHANA.

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 3.4, HL 0.90, HW 0.80, CI 89, EL 0.43, OI 54, SL 0.42, SI 53, PW 0.60, AL 0.94.

With the head in full-face view the sides behind the eyes denticulate, ending in a low triangular tooth at the occipital corner. Occipital margin with a small tooth close to the one at the corner but otherwise unarmed; the occipital crest absent, the dorsum rounding evenly into the occipital surface. Eyes relatively large, OI > 50. Alitrunk with promesonotum both longitudinally and transversely convex. In profile the alitrunk with its highest point at about the midlength of the pronotum, behind which the dorsum is evenly shallowly convex to the base of the propodeal spines. The steeply sloping anterior portion of the pronotal dorsum with a number of minute peaks or tubercles from which hairs arise, such peaks absent elsewhere on the dorsum. Tooth on mesokatepisternum moderately developed, distinct. Propodeal spines in profile scarcely elevated and almost straight, only very feeble downcurved along their length; not having the basal portions elevated and the distal portions recurved. With the alitrunk in dorsal view the pronotal corners with prominent acute dentiform angles. Pronotal margin behind the corners with 5-6 triangular, laterally projecting denticles which are quite evenly spaced. Sides of mesonoturn with two small denticles, the sides of the propodeum convex over the site of the spiracles, with one or two minute tubercles. Propodeal spines broad in dorsal view and evenly divergent. Petiole in profile rising to an acute peak dorsally. Subpetiolar process complex, with a blunt and strongly prominent anteroventral angle and a tooth-like projecting posteroventral angle, the two separated by a conspicuously concave ventral margin. Postpetiole in profile with the dorsal and posterior surfaces distinctly denticulate, the subpostpetiolar process elongate-digitiform. Dorsum of head irregularly reticulate-rugulose, the reticular meshes of varying size and the rugulae themselves low and rounded. Ground-sculpture within the meshes reduced to an inconspicuous vetigial shagreening, without punctures. Pronotal dorsum similarly but more strongly sculptured, with a few low broad transverse rugae anteriorly but with the longitudinal component predominating behind this. On the mesonotum and propodeum the longitudinal component of the sculpture predominates, the rugae being broader and more strongly developed; many of the cross-meshes are feeble or incomplete. Rugae between bases of propodeal spines transverse. Petiole in dorsal view regularly longitudinally rugose, the rugae converging posteriorly; the postpetiole irregularly rugose. Ground-sculpture of alitrunk as on head. First gastral tergite blanketed by dense reticulate-punctation, without strong basigastral rugulae but here and there with feeble short rugulae formed by the alignment of margins of adjacent punctures. First gastral sternite reticulate-punctate. Sides of pronotum transversely sulcate. Discounting the long hairs which arise around the eyes the dorsum of the head with numerous stalked-suborbicular hairs, the basal stems of which are quite short. Occipital surface with longer hairs which increase in thickness from base to apex. All remaining dorsal surfaces of body with numerous short stout blunt hairs. On the alitrunk some of these hairs are slightly thicker apically than basally, these hairs straight everywhere except on the base of the first gastral tergite where they are slightly back-curved. Colour uniform black; the scapes, tibiae and tarsi dull yellow.

Paratypes. TL 2.8-3.2, HL 0.74-0.86, HW 0.68-0.72, CI 86-92, EL 0.39-0.42, OI 54-57, SL 0.38-0.40, SI 53-56, PW 0.50-0.60, AL 0.78-0.92 (3 measured).

As holotype but averaging slightly smaller.

Type Material

Holotype worker, Ghana: Pankese, 24.ix.1968 (C. A. Collingwood) (The Natural History Museum). Paratype. Ghana: 1 worker with same data as holotype. Nigeria: 2 workers, Onipe, CRIN, 11.vi.1975, tree 47-16 (A63.1), black pod project (B. Taylor) (BMNH).

References