Cataulacus hispidulus

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Cataulacus hispidulus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. hispidulus
Binomial name
Cataulacus hispidulus
Smith, F., 1865

Cataulacus hispidulus P casent0280802.jpg

Cataulacus hispidulus D casent0280802.jpg

Specimen Label

Synonyms

Specimens have been collected on vegetation in rainforest.

Identification

A member of the granulatus group. Of the species immediately related to Cataulacus granulatus, Cataulacus hispidulus is the most easily distinguished. The shape of the petiole and its ventral process is distinctive and will effectively separate the species from all others in the Indo-Australian and Oriental regions, but the general body form of the worker renders it very easily identifiable when one is acquainted with the genus. The short, stocky build of the body, sharp rugoreticulum with shining interspaces and the abundant hairs form an easily recognizable combination of characters, not seen in any other ally of granulatus. (Bolton 1974)

Keys including this Species

Distribution

Known from Brunei Darussalam, Indonesia (Sumatra) and Malaysia (Sabah).

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo, Indonesia (type locality), Malaysia.

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)

Genetics

Polymorphic microsatellites have been identified for this species. (Debout et al. 2002)

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • hispidulus. Cataulacus hispidulus Smith, F. 1865: 76, pl. 4, fig. 7 (w.) INDONESIA (Sumatra). Bolton, 1974a: 66 (q.m.). Subspecies of granulatus: Dalla Torre, 1893: 138; Emery, 1924d: 298. Revived status as species: Donisthorpe, 1932c: 474. Senior synonym of brookei: Bolton, 1974a: 66.
  • brookei. Cataulacus brookei Forel, 1901e: 378 (w.q.m.) BORNEO. Junior synonym of hispidulus: Bolton, 1974a: 66.

The following notes on F. Smith type specimens have been provided by Barry Bolton (details):

Cataulacus hispidulus

Holotype worker in Oxford University Museum of Natural History. Labelled “Sum.”

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 1-6
Bolton (1974) - TL 4.6 – 5.8, HL 1.10 – 1.30, HW 1.31 – 1.50, CI 112 - 123, EL 0.40 – 0.48, OI 30 - 34, SL 0.64 – 0.72, SI 46 - 48, PW 1.14 – 1.25, AL l.14 – 1.22, MTL ca 0.70 (6 measured).

Occipital crest incomplete medially, the vertex rounding into the occiput. Occipital corners with a relatively large tooth followed by three or four smaller denticles along the occipital crest on each side. Sides of head behind eyes strongly denticulate. Edges of frontal carinae usually jagged, often more strongly so on the posterior than the anterior half, which in some cases is virtually smooth. Alitrunk with a massive appearance in dorsal view, short and broad, with the pronotal margins strongly denticulate. Propodeal spines narrow and short, each one less than half the length of the distance separating it from its twin. Petiole short and low in profile, the anterior face sloping gently into the very weakly convex dorsal surface. The latter curves posteriorly to the junction with the postpetiole, there being no distinct free posterior face to the petiole. Subpetiolar process large and complex, anteroventrally with a bluntly rounded angle or tooth and posteroventrally with a long, posteriorly directed spur. First gastral tergite short, broad, convex, not marginate laterally.

Sculpturation of dorsum of head and alitrunk a rather coarse and well-defined rugoreticulum, the interspaces of which are feebly reticulate-punctate and shining. First gastral tergite sculptured as alitrunk but the rugoreticulum much finer and the puncturation of the interspaces more distinct. Propodeal declivity finely and densely reticulate-punctate. All dorsal surfaces of head, body and appendages with abundant thick, blunt hairs, yellowish or white in colour and very distinct. On the head and alitrunk the hairs tend to arise from the points of intersection of the meshes of the reticulum.

Queen

Bolton (1974) - TL 7.2, HL 1.56, HW 1.66, CI 106, EL 0.50, OI 30, IOD 1.34, SL 0.74, SI 44, PW 1.54, AL 1.97, MTL 0.94.

As worker but denticulation of sides of head reduced to small, blunt tubercles. Propodeal spines shorter than in worker but still distinct. Subpetiolar process with the posteroventral spur more strongly developed, very long and conspicuous. First gastral tergite much longer than broad, length ca 2.40, width ca 1.70. Sculpturation of head and pronotum as worker with a similar arrangement of short, blunt hairs, but the interspaces of the rugoreticulum are less shiny and have
Bolton 1974 fig 38-41
a granular appearance. Mesoscutum and scutellum coarsely longitudinally rugose with a few transverse meshes, many of which are incomplete. First gastral tergite with an extremely fine rugoreticulum, coarsest basally, and a dense reticulate-puncturation. In the centre of the sclerite is a short, longitudinal strip which is virtually devoid of sculpturation and contrasts with the surrounding areas.

Male

Bolton (1974) - The head of the male examined (syntype of brookei) is missing. PW 0.92, A: 1.64, MTL 1.75.

Notauli well developed, the anterior arms with some distinct cross-ribs. Limits of the posterior arm poorly defined laterally, the groove distinct and broad. Parapsidal furrows absent or almost completely masked by the sculpturation, visible on one side as a slightly more shining strip in the syntype of brookei. Propodeal spines reduced to a pair of minute but acute teeth. Subpetiolar process short and blunt, without the posteroventral spur characteristic of the worker and female castes. Sculpturation of alitrunk a fine rugoreticulum, coarsest on the pronotum, the interspaces reticulate-punctate. Pedicel similarly sculptured but gaster with only a very fine, superficial reticulate-puncturation. Abundant short, thick white hairs present as in the other castes. Exposed portion of parameres smooth and shining, unsculptured apart from the pits from which hairs arise, strongly arcuate in ventral view.

Type Material

Bolton (1974):

Holotype worker, SUMATRA (A. R. Wallace) (UM, Oxford) [examined].

Cataulacus brookei Syntype workers, female, male, BORNEO: Sarawak (Haviland) (MHN, Geneva) [examined].

References

  • 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 66, queen, male described; Senior synonym of brookei)
  • Dalla Torre, K. W. von. 1893. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. Vol. 7. Formicidae (Heterogyna). Leipzig: W. Engelmann, 289 pp. (page 138, Variety of granulatus)
  • Debout, G., A. Dalecky, et al. (2002). "Isolation and characterization of polymorphic microsatellites in the tropical plant-ant Cataulacus mckeyi (Formicidae: Myrmicinae)." Mol. Ecol. Notes 2: 459-461.
  • Donisthorpe, H. 1932c. On the identity of Smith's types of Formicidae (Hymenoptera) collected by Alfred Russell Wallace in the Malay Archipelago, with descriptions of two new species. Ann. Mag. Nat. Hist. 10(10): 441-476 (page 474, Revived status as species)
  • Emery, C. 1924f [1922]. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [concl.]. Genera Insectorum 174C: 207-397 (page 298, Variety of granulatus)
  • Smith, F. 1865a. Descriptions of new species of hymenopterous insects from the islands of Sumatra, Sula, Gilolo, Salwatty, and New Guinea, collected by Mr. A. R. Wallace. J. Proc. Linn. Soc. Lond. Zool. 8: 61-94 (page 76, pl. 4, fig. 7 worker described)