Cataulacus taprobanae

AntWiki - Where Ant Biologists Share Their Knowledge
Jump to: navigation, search
Cataulacus taprobanae
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. taprobanae
Binomial name
Cataulacus taprobanae
Smith, F., 1853

Cataulacus taprobanae casent0900254 p 1 high.jpg

Cataulacus taprobanae casent0900254 d 1 high.jpg

Specimen Labels

Bingham (1903:121) encountered Cataulacus taprobanae wandering about 'apparently in an aimless sort of way' on the bark and leaves of trees. Their nests were made in hollow branches. It is also known to nest in Humboldtia laurifolia in Sri Lanka (Krombein et al. 1999) and has been observed foraging diurnally and feeding on extrafloral nectaries of Humboldtia brunonis in India (Gaume et al. 2005).

Photo Gallery

  • Cataulacus taprobanae worker from the Western Ghats, India. Photo by Kalesh Sadasivan.

Identification

A member of the taprobanae group. One of the relatively few species to inhabit the Indian subcontinent, Cataulacus taprobanae is distinguished by its long, divergent propodeal spines, reduced sculpturation dominated by puncturation and the presence of short, erect hairs on the alitrunk.

Keys including this Species

Distribution

Known from Sri Lanka and India.

Distribution based on Regional Taxon Lists

Oriental Region: India, Sri Lanka (type locality).
Palaearctic Region: China.

Distribution based on AntMaps

AntMapLegend.png

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.

  • taprobanae. Cataulacus taprobanae Smith, F. 1853: 225, pl. 20, fig. 10 (w.) SRI LANKA. Forel, 1909e: 393 (q.); Wheeler, G.C. & Wheeler, J. 1954b: 150 (l.); Bolton, 1974a: 83 (m.).

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) - TL 4.1 – 5.4, HL 1.02 – 1.32, HW 1.26 – 1.50, CI 112 - 123, EL 0.42 – 0.48, OI 32-33, IOD 0.96 – 1.20, SL 0.54 – 0.70, SI 41 - 47, PW 1.02 – 1.32, AL 1.22 – 1.54, MTL 0.64 – 0.82 (10 measured).

Bolton 1974 fig 30-34
Occipital crest complete or broken but always marked out by a series of denticles which decrease in size medially; those nearest the centre often minute. The crest itself shallowly concave across the width of the head. Sides of head behind eyes denticulate, the occipital corners with a small tooth which is, however, larger than the first denticle of the occipital crest. Sides of pronotum marginate, denticulate, but the sides of the mesonotum weakly or not marginate, with only one or two very small denticles. Propodeal spines long, stout and acute, divergent, the outer margins of the spines and the sides of the propodeum with a few minute denticles. First gastral tergite not marginate laterally.

Sculpturation of head and alitrunk primarily of a fine and dense reticulate-puncturation which overlies any rugulation present. The head with a fine loose rugoreticulum or with longitudinal rugae. Pronotum feebly reticulate-rugose, with the rugae tending to become longitudinal and less distinct posteriorly so that on the mesonotum the sculpturation is dominated by the puncturation and only a few feeble longitudinal rugulae are visible. Propodeum sculptured as mesonotum, the declivity usually with a few transverse rugae. First gastral tergite strongly reticulate-punctate with numerous weak longitudinal rugulae.

Dorsal surfaces of head, pedicel, first gastral tergite and appendages with numerous short, stout hairs, also present around the margins of the head and pronotum. Dorsum of litrunk with a few scattered hairs only.

Queen

Bolton (1974) - TL 6.8 – 7.0, HL 1.40 – 1.44, HW 1.48 – 1.58, CI 105 - 109, EL 0.48 – 0.50, OI 32, IOD 1.24 – 1.40, SL ca 0.72, SI ca 45, PW 1.44 – 1.48, AL 1.96 – 1.98, MTL 0.82 – 0.86 (3 measured).

Similar to worker but occipital crest incomplete medially, the median section broadly concave. Denticulation of crest and the sides of the head much reduced. Sides of pronotum with a few small denticles, the sides of the propodeum irregular but not denticulate. Propodeal spines a pair of short, broad, triangular teeth. Sculpturation basically as in worker but with the rugoreticulum of the head and pronotum more pronounced, the scutum and scutellum longitudinally and quite regularly rugose. Distribution of hairs as in worker but those on the head are shorter and less distinct. A transverse row of short hairs is present on the pronotum just anterior to the promesonotal suture.

Male

Bolton (1974) - TL 5.0 – 5.4, HL 1.04 – 1.12, HW 1.18 – 1.26, CI 111 - 117, EL 0.42 – 0.44, OI 34 - 35, IOD 0.98 – 1.04, SL 0.62 – 0.68, SI 49 - 54, PW 1.10 – 1.38, AL 1.72 – 1.82, MTL 0.80 – 0.84 (3 measured).

Occipital crest shallowly concave, usually complete but broken medially in some individuals. The crest denticulate, very feebly so medially, the largest denticles being those closest to the short, triangular occipital tooth. Sides of head behind eyes denticulate. Sides of pronotum irregular but not definitely denticulate. Notauli with only the anterior arms developed, and usually only the distal portions distinct and cross-ribbed; the posterior arm absent. Parapsidal furrows present. Propodeum with a pair of short but acute projecting teeth. Apical portions of parameres smooth and shining. Head and pronotum loosely reticulate-rugose, the rugae of the former raised into minute peaks at many of the points of intersection. Reticular inters paces finely and densely reticulate-punctate. Mesoscutum and scutellum finely longitudinally rugose, the gaster finely and densely reticulate-punctate with some basi gastric costulae present. Hairs numerous on all dorsal surfaces, much more conspicuous than in the other castes.

Type Material

Bolton (1974) - Holotype worker, CEYLON: (G. H. K, Thwaites) (BMNH) [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 83, male described)
  • Forel, A. 1909k. Études myrmécologiques en 1909. Fourmis de Barbarie et de Ceylan. Nidification des Polyrhachis. Bull. Soc. Vaudoise Sci. Nat. 45: 369-407 (page 393, queen described)
  • Gaume, L., M. Zacharias, V. Grosbois, and R. M. Borges. 2005. The fitness consequences of bearing domatia and having the right ant partner: experiments with protective and non-protective ants in a semi-myrmecophyte. Oecologia. 145:76-86.
  • Krombein, K. V. 1999. Biodiversity of the domatia occupants (ants, wasps, bees, and others) of the Sri Lankan myrmecophyte Humboldtia laurifola Vahl (Fabaceae). Smithsonian Contributions to Zoology No. 603, iv, 34 p.
  • Smith, F. 1853 [1854]. Monograph of the genus Cryptocerus, belonging to the group Cryptoceridae - family Myrmicidae - division Hymenoptera Heterogyna. Trans. Entomol. Soc. Lond. (2) 2: 213-228 (page 225, pl.20, fig. 10 worker described)
  • Wheeler, G. C.; Wheeler, J. 1954b. The ant larvae of the myrmicine tribes Cataulacini and Cephalotini. J. Wash. Acad. Sci. 44: 149-157 (page 150, larva described)