| Cataulacus theobromicola|
Nothing is known about the biology of Cataulacus theobromicola.
A member of the huberi group. The overall impression obtained from Santschi's description and figure is of a species closely related to Cataulacus pullus but separated from it by the structure of the lateral pronotal margins and the relative shortness of the propodeal spines. (Bolton 1974)
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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)
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- theobromicola. Cataulacus theobromicola Santschi, 1939c: 8, fig. 2 (w.) DEMOCRATIC REPUBLIC OF CONGO. See also: Bolton, 1974a: 28.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Bolton (1974) - TL 6.5, CI 118, OI 27 (CI and OI are approximated from the figure accompanying the original description).
Occipital corners with a single tooth; the occipital margin not denticulate and apparently without an occipital crest of any form. Sides of head behind eyes crenulate posteriorly, close to the corners. Pronotum marginate laterally, the anterior and posterior angles of the margins acute but not projecting. Pronotal margins without denticles but with a single triangular tooth in the anterior halves of their lengths. Mesonotum and propodeum not marginate, without denticles. Promesonotal suture and metanotal groove feebly marked by impressions. Propodeal spines short but acute.
Entirety of head and body dorsally finely reticulate-punctate, the head and alitrunk with a fine rugoreticulum which is finer and denser upon the alitrunk than upon the head. Petiole dorsally very coarsely longitudinally rugose. Sides of head behind eyes with a row of laterally projecting short, stout hairs. Hairs absent from dorsum of head and alitrunk; present around mouth and at apex of gaster.
Bolton (1974) - Holotype worker, ZAIRE: Gazi, in cocoa tree, xii. 1937 (Beinaert) (location of type not known).
- 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 28, see also)
- Santschi, F. 1939c. Trois notes sur quelques fourmis du Musée Royal d'Histoire Naturelle de Belgique. Bull. Mus. R. Hist. Nat. Belg. 15(1 14: 1-15 (page 8, fig. 2 worker described)