Cataulacus lobatus

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Cataulacus lobatus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. lobatus
Binomial name
Cataulacus lobatus
Mayr, 1895

Cataulacus lobatus P casent0280804.jpg

Cataulacus lobatus D casent0280804.jpg

Specimen Label

Nothing is known about the biology of Cataulacus lobatus.

Identification

A member of the huberi group. Cataulacus inermis is the closest related species to Cataulacus lobatus, but the former lacks propodeal spines and has distinctive transverse sculpturation upon the propodeal dorsum as well as the declivity.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Cameroun (type locality), Democratic Republic of Congo.


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.

  • lobatus. Cataulacus lobatus Mayr, 1895: 126, fig. 1 (w.) CAMEROUN. See also: Bolton, 1974a: 23.

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 fig 7-9

Bolton (1974) - TL 6.1, HL 1.52, HW 1.76, CI 116, EL 0.48, OI 27, IOD 1.46, SL 0.88, SI 56 PW 1.56, AL 1.80, MTL 1.04.

Occipital crest developed at each side but almost obliterated medially, visible only from certain angles, shallowly concave, unarmed. Occipital corners acute, almost right-angular but without differentiated teeth or denticles. Sides of head behind eyes irregular but not denticulate. Pronotum marginate, the margins expanded laterally but without teeth or denticles. Remainder of alitrunk not marginate, without denticles. Track of promesonotal suture represented upon the dorsal alitrunk by an extremely faint impression. Propodeum with a pair of short, narrow but acute spines. Petiole in dorsal view distinctly longer than broad; postpetiole divided into a pair of lobes dorsally by a longitudinal median impression. Sides of first gastral tergite marginate to the level of the spiracle; the margination most acute basally, rapidly becoming more obtuse nearer the spiracle itself.

Dorsum of head behind clypeus very finely reticulate-punctate with a faint, loose overlying rugoreticulum. The latter is strongest and most distinct behind the eyes but is very much effaced medially, in places virtually absent. Dorsal alitrunk similarly sculptured, the puncturation more marked than upon the head, and the sides of the propodeal dorsum with a few longitudinal rugae converging upon the bases of the spines. Propodeal declivity strongly transversely rugose throughout its depth. Dorsal surfaces of petiole and postpetiole coarsely longitudinally sulcate-rugose. First gastral tergite strongly reticulate-punctate with a few short rugulae.

Erect hairs absent from dorsal surfaces of head, alitrunk and gaster; present on the lateral margins of the head and the appendages.

Type Material

Bolton (1974) - Holotype worker, CAMEROUN: Kriegsschiffhafen, 15.iii.1892 (Brauns) (MN, Vienna) [examined]. The holotype is badly damaged, with both the head and the gaster missing.

References