Ponera colaensis

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Ponera colaensis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Ponera
Species: P. colaensis
Binomial name
Ponera colaensis
Mann, 1921

Ponera colaensis P casent0194711.jpg

Ponera colaensis D casent0194711.jpg

Specimen Label

My collections were made in disturbed rain forest in the Nandarivatu Forestry Nature Preserve at 840 m, and from relatively undisturbed forest on the slopes of Mt Lomolaki, at about 900 m. The majority of the specimens were taken from Berlese funnel samples of leafmold, moss off rotting logs, or debris from a tree fern stump. Accession No. 29 consisted of several workers taken with pupae under spongy moss covered bark on a rotting log. (Taylor 1967)

Identification

Taylor (1967) - One of the larger members of the taipingensis species group; somewhat similar to the Malayan Ponera taipingensis, but distinguished from it by the narrower head and wider petiolar node (cephalic index 8 1-83, petiolar node index 88-91 as opposed to 84-86 and 84-85 respectively in taipingensis). Ponera syscena (New Guinea) and Ponera loi (Samoa) are both similar to colaensis, but they have much narrower petiolar nodes (PNI 79-82 in syscena, 78-82 in loi).

P. colaensis is the only known Fijian Ponera species lacking an incised dorsal mesometanotal suture. The other Fijian species are all smaller, except for the slightly larger Ponera manni (HW 0.57 mm in the unique holotype), which has a much narrower petiolar node (PNI 73 opposed to 88-91 in colaensis).

The unique known queen of colaensis differs from those of the related P. loi by her smaller size, longer scapes, and broader petiolar node (HW 0.54 mm; SI 91; PNI 82, opposed to 0.60-0.63 mm; 83 -87, and 75-76 respectively in P. loi).

Keys including this Species

Distribution

A species apparently endemic to the Fiji Is. (Viti Levu and Lau group).

Distribution based on Regional Taxon Lists

Indo-Australian Region: Fiji (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Beyond some habitat information from collection labels not much is known about Ponera colaensis.

The general biology of species in the genus was summarized by Taylor (1967): Ponera are small ants that nest in rotting logs in forested areas or under stones in nonforested situations. In the tropical areas specimens are rarely encountered away from rain forest. In temperate areas, however, species may occur in relatively lightly forested areas. This appears to be the case with Ponera japonica, Ponera pennsylvanica and especially with Ponera coarctata. The Australian Ponera leae is essentially limited to rain forest in the northern parts of its range, but further south it may be found in dry, lightly forested areas.

Foraging is probably cryptobiotic, though some New Guinea species have been taken straying on the ground surface. Little information is available concerning feeding. However, most species are probably insectivorous. I have conducted feeding experiments with some of the New Guinea and Samoan species, including Ponera xenagos, Ponera elegantula, Ponera tenuis, Ponera incerta and Ponera woodwardi. These were unsuccessful with the larger species, except elegantula, which accepted moderately large (8-12 mm) campodeid and japygid Diplura. Tenuis and incerta accepted smaller (4-6 mm) campodeids, isotomid and sminthurid Collembola, and small newly hatched spiders (2 mm long). Negative feeding response was obtained with eggs and larvae of various ants, small crushed insects of various orders, and small myriapods. Stray workers were never observed carrying prey, and distinct middens of insect or other remains were not located near nests.

Colonies usually contain about 30 workers. Larvae and pupae are not segregated in most cases, but occasionally aggregations of pupae were observed. These may have included the total brood of the colonies involved. Larvae are attached to the floor or walls of the nest galleries by the glutinous abdominal tubercles described above, and the ants move them high up on the walls or ceilings of artificial nests, if they are flooded. Details of nuptial behavior of pennsylvanica were given by Wheeler (1900), and Haskins & Enzmann (1938). The flights appear to be of a pattern typical for ants, with the alates meeting in the air and mating there or on the ground. Colony foundation is non-claustral and independent in pennsylvanica (Kannowski 1959); judging from my observations this is typical for the genus.

Castes

Male and larva unknown; pupae of all castes enclosed in cocoons. (Taylor 1967)

Nomenclature

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

  • colaensis. Ponera colaensis Mann, 1921: 417 (w.) FIJI IS. Santschi, 1928c: 68 (q.). See also: Taylor, 1967a: 58.

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

Description

Worker

Taylor 1967 Ponera fig 43-54

Taylor (1967) - The following dimensions are those of the holotype (USNM) and a single worker (MCZ) with labels identical to those of the holotype. This latter specimen was apparently overlooked by Mann at the time of description of the species. HL 0.62 mm, 0.61 mm; HW 0.50 mm; SL 0.45 mm; CI 81, 82; SI 90; PW 0.42 mm, 0.40 mm; PNL 0.20 mm; PH 0.43 mm; DPW 0.37 mm, 0.36 mm; PNI 88, 90.

Thirty additional workers I collected at Nandarivatu, Viti Levu, have the following measurements and indices: HL 0.62-0.65 mm; HW 0.50-0.54 mm; SL 0.46-0.49 mm; CI 81 -83; SI 88-92; PW 0.41-0.44 mm; PNL 0.20-0.22 mm; PH 0.41-0.43 mm; DPW 0.36-0.38 mm; PNI 88-91.

Mann's diagnosis is generally adequate, but the following additional notes are pertinent:

1. Clypeus with vestigial median anterior tooth, in the form of a bluntly pointed low tumosity.

2. Palpal formula: Maxillary 2: Labial 2 (3 Nandarivatu specimens dissected).

3. Eyes with maximum diameter ranging from 0.02 mm t o almost 0.04 mm, with 3-5 rather indistinct facets; their anterior borders situated about 0.87 X the distance from lateral occipital border to midpoint of anterior genal border.

4. Scapes almost exactly attaining median occipital border-in smaller specimens they may fail to do so by a very slight margin (less than 1/4 their maximum thickness).

5. Dorsal mesometanotal suture never distinctly incised, although in several specimens it is represented by a shallow broad transverse impression. Lateral mesonotal suture distinctly marked. Sides and declivitous face of propodeum almost straight in dorsal view. Posterolateral corners of propodeum slightly raised, forming angles of about 90° when viewed from above.

6. Erect to sub-erect pilosity sparse on mandibles, clypeus, frontal lobes, dorsa of mesosoma and node, and entire gaster; more sparse on front of head and more abundant on gaster. Distinct whitish adpressed pubescence everywhere abundant.

7. The holotype and Mann's Waiyanitu specimen are rich medium reddish brown in color. They may possibly have been semi-callow when taken, or else affected by preservation, as the remaining material is darker. The Nandarivatu examples are uniformly very dark reddish brown, with mandibles, antennae, legs, and gastric apex a bright rich yellowish brown.

Queen

Taylor (1967) - A single alate specimen collected with workers at Nandarivatu (my accession no. 35) has the following characters: HL 0.65 mm; HW 0.54 mm; SL 0.49 mm; CI 83; SI 91; PW 0.49 mm; PNL 0.22 mm; PH 0.47 mm; DPW 0.40 mm; PNI 82; maximum diameter of eye 0.18 mm; ocular index 33. Conforming to the general plan of queen structure for the genus. Wing venation of the Ponera coarctata type. Differing from the workers in the usual characters of full sexuality, and agreeing with them in color, sculpturation and pilosity. The median clypeal denticle is reduced to an indistinct low tumosity as in the workers. When laid back along the head the scapes almost exactly reach the median occipital border.

Type Material

Taylor (1967) - Waiyanitu, Viti Levu, Fiji Is. (holotype examined-National Museum of Natural History).

References

  • Mann, W. M. 1921. The ants of the Fiji Islands. Bull. Mus. Comp. Zool. 64: 401-499 (page 417, worker described)
  • Santschi, F. 1928c. Fourmis de îles Fidji. Rev. Suisse Zool. 35: 67-74 (page 68, queen described)
  • Sarnat, E. M.; Economo, E. P. 2012. The ants of Fiji. University of California Publications in Entomology 132:1-384. PDF
  • Taylor, R. W. 1967a. A monographic revision of the ant genus Ponera Latreille (Hymenoptera: Formicidae). Pac. Insects Monogr. 13: 1-112 (page 58, see also)