Cataulacus huberi

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Cataulacus huberi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. huberi
Binomial name
Cataulacus huberi
André, 1890

Cataulacus huberi P casent0217826.jpg

Cataulacus huberi D casent0217826.jpg

Specimen Label

Synonyms

Specimens found individuals running on a moss-covered tree trunk in Ghana primary forest. D. Leston collected specimens from this same area (Mt. Atewa) using pyrethrum knock-down sampling. Specimens from other areas have also been found in forest habitats.

Identification

A member of the huberi group Without a doubt Lasius huberi is amongst the most variable of species as concerns sculpturation. It is nonetheless easily recognizable by its combination of the following characters: pedicellar segments transverse and strongly transversely sculptured; gaster with the first tergite strongly marginate and the first sternite carinate laterobasally; sides of head denticulate or crenulate, with a distinct series of projecting hairs. The most closely related species, Cataulacus egenus, is separated by the characters given in the key. (Bolton 1974)

Keys including this Species

Distribution

Known from Democratic Republic of Congo, Ghana, Nigeria, Sierra Leone, and Uganda.

Distribution based on Regional Taxon Lists

Afrotropical Region: Cameroun, Democratic Republic of Congo, Ghana, Malawi, Sierra Leone (type locality), Uganda, United Republic of Tanzania.

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.

  • huberi. Cataulacus huberi André, 1890: 326 (w.) SIERRA LEONE. André, 1895a: 4 (q.); Bolton, 1974a: 20 (m.). Senior synonym of guilelmi, herteri, longispinus and material of the unavailable name luebensis referred here: Bolton, 1974a: 19.
  • longispinus. Cataulacus huberi var. longispinus Stitz, 1910: 139, fig. 8 (w.) CAMEROUN. Subspecies of huberi: Wheeler, W.M. 1925b: 2. Junior synonym of huberi: Bolton, 1974a: 19.
  • herteri. Cataulacus huberi r. herteri Forel, 1913b: 315 (w.) DEMOCRATIC REPUBLIC OF CONGO. Junior synonym of huberi: Bolton, 1974a: 19.
  • guilelmi. Cataulacus huberi subsp. guilelmi Wheeler, W.M. 1925b: 1 (w.) DEMOCRATIC REPUBLIC OF CONGO. Junior synonym of huberi: Bolton, 1974a: 19.

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

Of the described, and now synonymized infraspecific taxa formerly attached to huberi, the majority were based upon sculptural variations, and these immediately fell into the synonymy. In the var. longispinus, apart from some sculptural variation, Stitz noted that there were three prothoracic spines on each side and relatively long propodeal spines. The latter are well within the range observed during the present study and as has been noted the number of pronotal spines or teeth may vary from 0 to 4. In fact the race herteri, reported by Forel as having no teeth upon the pronotum, has two such processes developed in at least two of the syntype workers in existence. (Bolton 1974)

Description

Worker

Bolton (1974) - TL 5.5 – 7.8, HL 1.22 – 1.74, HW 1.60 – 2.30, CI 127 - 132, EL 0.42 – 0.56, OI 26 - 29, IOD 1.20 – 1.84, SL 0.76 – 1.04, SI 45 - 48, PW 1.28 – 2.10, AL 1.44 – 2.l0, MTL 0.86 – 1.24 (10 measured).

Bolton 1974 fig 10-12

Occipital crest usually developed as an unarmed ridge or acute angle separating vertex from occiput. In shape it may be broadly but shallowly concave across the width of the head or more strongly concave in the middle portion than elsewhere. The crest may be reduced or even absent in some smaller members of the species. Occipital corners acute, usually without a posteriorly projecting tooth but with a laterally projecting dentiform angle. Sides of head behind eyes usually denticulate or crenulate, rarely only irregular. Pronotum strongly marginate laterally, the margination either entire or more usually broken up into 1 to 4 separated, projecting dentiform or blunted processes, sometimes the number of these processes different on each side of the same individual. When the margination is entire then the edge is often crenulate or otherwise jagged. Remainder of alitrunk not marginate, without denticles. Propodeum with a pair of long, acute spines. Dorsal surface of petiole flattened, rectangular or subrectangular in shape, the sides of the posterior face converging. Postpetiole strongly transversely expanded, usually distinctly broader than the petiole. Subpetiolar process well developed, variable in shape and size; subpostpetiolar process usually a long, acute tooth. Both the tergite and the sternite of the first gastral segment strongly or very strongly marginate or carinate laterobasally, these structures tending to fade out before reaching the midlength of the segment.

Sculpturation very variable. The head is usually finely and sparsely reticulate-rugose with reticulate-punctate interspaces, more rarely with the rugulations adopting a longitudinal or arcuate direction. On the dorsal alitrunk all intergrades are known between a distinct longitudinal sulcate-rugulation and a finely shagreened surface with one or two weak rugulae. However, the most common form of sculpturation appears to be a very fine and quite dense longitudinal rugulation with the spaces between the rugulae reticulate-punctate. On the anterior portion of the pronotum the rugulae tend to be transverse. Petiole and postpetiole strongly transversely sulcate-rugose. First gastral tergite usually densely reticulate-punctate, often with numerous longitudinal rugulae, especially basally. Erect hairs absent from dorsal surfaces of head and body, present upon appendages and with a row of distinct short hairs freely projecting laterally beyond the margins of the sides of the head behind the eyes.

Queen

Bolton (1974) - TL 8.0, HL 1.70, HW 2.00, CI 116, EL 0.54, OI 27, IOD 1.68, SL not measurable, PW 1.80, AL 2.30, MTL 1.12.

Answering to the description of the worker but the pronotal marginations not so broadly expanded and the rugulation of the mesoscutellum and propodeum strongly transverse. Propodeal spines greatly reduced in length, present here as a pair of broad, blunt teeth. The female may in fact be as variable as the worker, but collections of this caste are extremely scarce.

Male

Bolton (1974) - TL 6.8, HL 1.20, HW 1.42, CI 118, EL 0.40, OI 28, IOD 1.16, SL 0.66, SI 46, PW 1.36, AL 1.94, MTL 1.02.

Occipital crest absent, the occipital corners projecting as broadly triangular processes. Sides of head behind eyes strongly denticulate. Sides of pronotum sharply but narrowly marginate, not expanded as in the worker, nor armed with teeth. Anterior arms of notauli well developed and strongly cross-ribbed, the posterior arm absent. Parapsidal furrows very distinct. Propodeum with a pair of long, acute spines which are very broad basally. Petiole and postpetiole basically similar in shape to that described for the worker, with similar ventral processes. A faint trace of margination is visible on the first gastral tergite in front of the spiracle, and a short weak carina parallels it upon the sternite. Sculpturation is everywhere of a fine, dense reticulate-puncturation with a few scattered rugulae, which form a loose reticulum behind the eyes. The propodeal dorsum is more strongly rugose and the segments of the pedicel show sculpturation similar to, though less well developed than the worker. Short erect hairs are present and distinct upon the dorsal surfaces of the alitrunk and gaster, but are limited to two upon the vertex.

Type Material

Bolton (1974):

Syntype workers, SIERRA LEONE (A. Mocquerys) (MNHN, Paris) [examined].

Cataulacus huberi var. longispinus. Holotype worker, CAMEROUN: Mundame (Conradt) (MNHU, Berlin) [examined].

Cataulacus huberi race herteri. Syntype workers, ZAIRE: Katanga, Welgelegen 14.vi.1912 (Bequaert) (MHN, Geneva; MRAC, Tervuren; MNHU, Berlin) [examined].

Cataulacus huberi subsp. guilelmi. Holotype worker, ZAIRE: Ituri (location of type not known).

Cataulacus huberi st. herteri var. luebensis. Syntype workers, ZAIRE: Luebo, Kamajembi, 22.iX.1921 (H. Schouteden) (NM, Basle) [examined].

References