Cataulacus boltoni

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Cataulacus boltoni
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. boltoni
Binomial name
Cataulacus boltoni
Snelling, R.R., 1979

Cataulacus boltoni P casent0900269.jpg

Cataulacus boltoni D casent0900269.jpg

Specimen Label

Nothing is known about the biology of Cataulacus boltoni.

Identification

Worker: Dorsal cephalic hairs clavate to subspatulate; propodeal rugae transverse; sides of pronotum not marginate.

A member of the tenuis group readily distinguished from other group members by the combination of bizarre cephalic hairs, transversely rugose propodeal base and nonmarginate mesosomal dorsum. In this last character it is most like Cataulacus vorticus but differs from vorticus in the much stronger mesosomal sculpturation, the transversely rugulose propodeal base and the longer, stouter and more numerous setae of the first gastric tergum. The hairs of the cephalic dorsum are longer than in vorticus, especially on the vertex and occiput. (Snelling 1979)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Nigeria (type locality).

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.

  • boltoni. Cataulacus boltoni Snelling, R.R. 1979a: 3, figs. 1-8 (w.) NIGERIA.

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

Description

Worker

Holotype Worker. TL 2.74; HL 0.76; HW 0.72; CI 95; EL 0.38; OI 53; IOD 0.53; SL 0.37; SI 52; PW 0.50; WL 0.78; MTL 0.28.

Occipital crest absent; occipital margin raised, with low, blunt denticles, one on occipital corner and one mesad of it, several located behind eye. Preocular denticle small, separated from eye by a small gap. Pronotum not marginate laterally, humeral angle dentiform; side with minute denticle at about midlength and a larger one at promesonotal junction. Mesonotum and propodeum not marginate, with a couple of widely spaced, minute denticles on each side; propodeal spines short and bluntly rounded apically. Promesonotal and mesometanotal grooves absent on dorsum. Sides of propodeum, in dorsal view, distinctly convergent posteriorly, those of mesonotum straight, more strongly convergent and separated from propodeum by a narrow V-shaped notch. First gastric tergum not marginate at sides.

Dorsum of head moderately shiny, finely rugoreticulate, the interspaces finely and densely reticulate-punctate, the punctures shallow. Mesosomal dorsum less shiny, with irregular close-set, longitudinally oriented rugulae, strongest at sides, those on posterior part of mesonotum and base of propodeum sharp, transverse; interspaces densely reticulate-punctate. Dorsal surface of petiole and postpetiole sharply longitudinally rugose. First gastric tergum finely and densely reticulate-punctate throughout, no longitudinal rugulae at base.

Holotype Specimen Labels

Hairs on clypeus and cephalic dorsum bizarre, stout and short to medium, clavate to subspatulate. Hairs on meso- and metasoma numerous, stout and medium length on dorsum and sides, slender on venter.

Type Material

Holotype worker, NIGERIA: Gambari, 24 May 1975 (B. Taylor), in British Museum (Natural History).

Etymology

This species is dedicated to Mr. Barry Bolton, who recognized the novelty of this species and sent it to me for inclusion in this paper.

References

  • Snelling, R. R. 1979a. Three new species of the Palaeotropical arboreal ant genus Cataulacus (Hymenoptera: Formicidae). Contr. Sci. (Los Angel.) 315: 1-8 (page 3, figs. 1-8 worker described)