Cataulacus catuvolcus

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Cataulacus catuvolcus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. catuvolcus
Binomial name
Cataulacus catuvolcus
Bolton, 1974

Cataulacus catuvolcus P casent0900257.jpg

Cataulacus catuvolcus D casent0900257.jpg

Specimen Label

Cataulacus catuvolcus forms small colonies of less than 100 workers. Their nests are formed within small dead twigs (Maschwitz and Moog 2000).

Identification

Bolton (1974) - The species belongs to the small complex in the taprobanae group centering on reticulatus, It is distinguishable from Cataulacus reticulatus and its immediate allies by the combined presence of a sharp occipital crest which is not raised medially, a marginate first gastral tergite, and by the form of the sculpturation upon the dorsal alitrunk.

Keys including this Species

Distribution

The type-series is from Romblon Is, but it seems that the species is also present upon Luzon as a damaged male from Benguet, Luzon Is. collected by C. F. Baker is almost certainly referable to this species.

Distribution based on Regional Taxon Lists

Indo-Australian Region: Philippines (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.

  • catuvolcus. Cataulacus catuvolcus Bolton, 1974a: 74, figs. 4, 37 (w.q.m.) PHILIPPINES.

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

Description

Worker

Holotype. TL 4.8, HL 1.12, HW 1.32, CI 118, EL 0.44, OI 33, IOD 1.04, SL 0.60, SI 45, PW 1.10, AL 1.20, MTL 0.64.

Bolton 1974 fig 35-37
Occipital crest well developed, sharp, not denticulate, shallowly concave. Sides of head behind eyes weakly denticulate, terminating at the occipital corner in a small, triangular tooth. Margins of frontal carinae sinuate, not jagged nor denticulate, the preocular tooth low and very broad. Lateral margins of pronotum uneven, not denticulate but with four or five small prominences which give the margin a minutely wavy appearance. Margins of mesonotum unarmed, with a narrow but conspicuous notch between the mesonotum and propodeum which gives the latter a short, free anterior face on each side. Sides of propodeum and outer margins of the spines with a few small prominences, the spines themselves long, broad basally and tapering to an acute apex. Petiole subconical in profile, the anterior face sloping steeply backwards and meeting the confluent, sloping dorsal and posterior face in an acute angle. This angle is visible as a weak transverse ridge in dorsal view, with a short and steeply sloping face in front and a longer and more gradually sloping face behind. Sides of first gastral tergite marginate throughout their length.

Head and body everywhere finely and densely reticulate-punctate, this sculpturation overlying any rugation which is present. Dorsum of head with a fine, rather loose rugoreticulum, faint traces of which also occur on the pronotal dorsum. The remainder of the dorsal alitrunk is equipped with numerous low, rounded, regular and virtually parallel longituuinal rugae which do not extend onto the propodeal declivity. Dorsum of first gastral tergite with numerous short, faint longitudinal rugulae, more obvious towards the sides of the sclerite than on the disc.

Dorsal surfaces of head and alitrunk without erect hairs, but the margins of the frontal carinae and of the head behind the eyes support a row of laterally projecting, short hairs. Lateral margins of alitrunk with a few short, very small hairs. Dorsal surfaces of legs, postpetiole and posterior half of first gastral tergite 'with erect hairs, often minute.

Paratypes. TL 4.2 – 4.8, HL 1.06 – 1.14, HW 1.26 – 1.32, CI 114 - 119, EL 0.42 – 0.46, OI 33 - 35, IOD 0.98 – 1.04, SL 0.54 – 0.60, SI 43 - 45, PW 0.98 – 1.10, AL 1.16 – 1.22, MTL 0.58 – 0.64 (7 measured).

As holotype but with the pronotal sculpturation somewhat variable. In most the rugoreticulum is more or less distinct, but the cross-meshes may be effaced or partially effaced, leaving the sclerite longitudinally sculptured as the remainder of the dorsal alitrunk. In many specimens the longitudinal rugae of the dorsum tend to continue for a short distance onto the propodeal declivity.

Queen

Bolton 1974 fig 1-6
Paratypes. TL 5.1 – 6.0, HL 1.12 – 1.24, HW 1.30 – 1.40, CI 113 - 116, EL 0.44 – 0.48, OI 32 - 34, IOD 1.04 – 1.10, SL 0.56 – 0.60, SI 42 - 43, PW 1.18 – 1.30, AL 1.46 – 1.60, MTL 0.68 – 0.70 (3 measured).

As worker but denticulation of sides of head further reduced. Pronotum and propodeum constructed much as in worker but the spines of the latter proportionately shorter and broader. Lateral margination of the first gastral tergite absent or with the side portions of the sclerite meeting the dorsum in an obtuse angle. Sculpturation of head as in worker, pronotum longitudinally rugose with some reticulation at the sides. Mesoscutum with a faint, regular, more or less parallel longitudinal rugulation. The rest of the alitrunk similarly but more coarsely sculptured, usually with some weak cross-meshes on the scutellum and with the rugae diverging on the propodeum.

Male

Paratypes. TL ca 5.1, HL 0.84 – 0.90, HW 1.06 – 1.10, CI 118 - 130, EL 0.40 – 0.42, OI 36 - 40, IOD 0.82 – 0.88, SL 0.50 – 0.52, SI ca 47, PW 0.90 – 0.98, AL 1.36 – 1.50, MTL 0.66 – 0.70 (2 measured).

Occipital crest sharp and distinct, unarmed. Sides of head behind eyes denticulate, the occipital corners with a small tooth. Frontal groove visible as a polished strip of cuticle, not reaching the median ocellus. Sides of pronotum and propodeum irregular but without denticles; propodeal spines strongly developed, broad and acute. Notauli almost or quite absent. In the larger specimen the path of the anterior arms is visible, but in the smaller only a very weak indentation marks their former position; the posterior arm is not developed. Sides of first gastral tergite marginate for about two thirds of their length, the margination most distinct anteriorly, gradually fading out behind. Sculpturation of dorsal surfaces of head and alitrunk a fine rugoreticulum with punctate interspaces, the rugae tending to have a longitudinal direction on the scutum. Gaster and the strongly sclerotized apical portions of the parameres finely reticulate-punctate.

Paratype Specimen Labels

Type Material

Holotype worker, PHILIPPINES: Romblon Island, 2.V.1924 (J. W. Chapman) (MCZ, Boston).

Paratypes. 8 workers, 3 alate females (one with gaster missing) and 2 males, with same data as holotype (MCZ, Boston; BMNH).

References