Iridomyrmex viridiaeneus

Iridomyrmex viridiaeneus
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Dolichoderinae
Tribe:	Leptomyrmecini
Genus:	Iridomyrmex
Species:	I. viridiaeneus
Binomial name
Iridomyrmex viridiaeneus Viehmeyer, 1914

Iridomyrmex viridiaeneus is the most widely distributed of the meat ants, and occurs throughout Australia. Its compound nests and habits, at least in Western Australia, approximate those of species like Iridomyrmex purpureus.

Photo Gallery

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  Iridomyrmex viridiaeneus worker, Morgan, South Australia. Photo by Mark Newton.
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  Iridomyrmex viridiaeneus worker, Morgan, South Australia. Photo by Mark Newton.
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  Iridomyrmex viridiaeneus with a bush fly prey item. Morgan, South Australia. Photo by Mark Newton.

Identification

This ant is distinguished by its strong green iridescence, in addition to purple or pink iridescence, and its uniformly dark, reddish integument. With older, pinned material, workers of this species may be a little difficult to distinguish from Western Australian workers of I. purpureus with yellowish- to bluish-green humeri and a bluish- green frons, but the green colour in I. viridiaeneus is quite distinct on the sides of the head capsule when the ant is seen in profile, whereas this is not the case with the I. purpureus variant. Other intraspecific variations seen in Western Australian workers (i.e., a tendency to reddish iridescence, and a more arched posterior pronotum), are discussed by Shattuck (1993 a). Shattuck also mentions in his monograph a small form of I. viridiaeneus (called ‘SB’ by the earlier researchers Greenslade and Halliday (1982)), which he considered to be conspecific with the typical, larger form.

Keys including this Species

• Key to Iridomyrmex of the southwestern Australian Botanical Province
• Key to Iridomyrmex species

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 32.56553333° to -35.2°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

Australasian Region: Australia (type locality).

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Biology

Greenaway (1981) examined trailing activity in this species. He found it restricted to the hours of daylight and further limited by the temperature of the air surrounding the ant (T,) and by the net radiant heat load. Activity in winter begins well after sunrise and continues until late afternoon averaging c. 7.4 h per day. Midsummer activity occupies two distinct periods, one commencing at dawn and the other in late afternoon; the two together total about 6.8 h per day. The upper and lower values of T, between which ants are active are 43.5°C and 14°C. Radiant heat input is dissipated from the ants by convective heat loss.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

• viridiaeneus. Iridomyrmex detectus var. viridiaeneus Viehmeyer, 1914b: 41 (w.) AUSTRALIA. Wheeler, W.M. 1915g: 811 (q.). Wheeler, G.C. & Wheeler, J. 1974b: 400 (l.). Raised to species: Wheeler, G.C. & Wheeler, J. 1974b: 400. Subspecies of purpureus: Greenslade, 1974: 247; Taylor & Brown, D.R. 1985: 102. Raised to species: Shattuck, 1993a: 142. See also: Shattuck, 1994: 113; Heterick & Shattuck, 2011: 155.

Type Material

• Iridomyrmex detectus viridiaeneus: Syntype, 1 worker, Killalpaninna, South Australia, Australia, Australian National Insect Collection.
• Iridomyrmex detectus viridiaeneus: Syntype, 2 worker, Killalpaninna, South Australia, Australia, Musee d'Histoire Naturelle Genève.
• Iridomyrmex detectus viridiaeneus: Syntype, 3 workers, Killalpaninna, South Australia, Australia, Naturhistorisches Museum, Basel.
• Iridomyrmex detectus viridiaeneus: Syntype, 1 worker, Killalpaninna, South Australia, Australia, National Museum of Natural History.

Description

Worker Description. Head. Posterior margin of head weakly concave; erect setae on posterior margin in full- face view set in a row; sides of head noticeably convex; erect genal setae absent from sides of head in full-face view (one to a few small setae may be present near mandibular insertion). Ocelli absent; in full-face view, eyes set above midpoint of head capsule; in profile, eye set anteriad of head capsule; eye semi-circular. Frontal carinae convex; antennal scape surpassing posterior margin of head by approximately 2 x its diameter. Erect setae on scape present and abundant; prominence on anteromedial clypeal margin projecting as triangular spur; mandible elongate triangular with oblique basal margin; long, curved setae on venter of head capsule present in some workers. Mesosoma. Pronotum moderately and evenly curved over its length. Erect pronotal setae numerous (12 or more), short and bristly. Mesonotum sinuous. Erect mesonotal setae numerous (12 or more), short and bristly. Mesothoracic spiracles always prominent as small, vertical protuberances; propodeal dorsum smoothly and evenly convex; placement of propodeal spiracle posteriad and near propodeal declivity, or mesad, more than its diameter away from propodeal declivity; propodeal angle weakly present or absent, the confluence of the dorsal and declivitous propodeal faces indicated, if at all, by an undulation. Erect propodeal setae numerous (12 or more), short and bristly. Petiole. Dorsum of node acuminate, or convex; node thin, scale-like, orientation more-or-less vertical. Gaster. Non- marginal erect setae of gaster present on first gastral tergite; marginal erect setae of gaster present on first tergite. General characters. Allometric differences between workers of same nest present. Colour foreparts shades of reddish-brown, head often slightly lighter in colour, gaster dark reddish-brown, iridescence on head and pronotum predominantly bright yellowish-green to emerald green, mesonotum, propodeum and legs also with pink to purple iridescence in pinned material, gaster with iridescence of rainbow hues. Colour of erect setae brown.

Measurements. Worker (n = 71)—CI 89–101; EI 17–22; EL 0.29–0.41; EW 0.18–0.26; HL 1.55–2.37; HW 1.40–2.34; ML 0.73–1.37; PpH 0.19–0.47; PpL 0.73–1.32; SI 84–108; SL 1.5 1–2.05.

References

• Greenaway, P. 1981. Temperature limits to trailing activity in the Australian arid-zone meat ant Iridomyrmex purpureus form viridiaeneus. Australian Journal of Zoology 29, 621-630.
• Greenslade, P. J. M. 1974a. The identity of Iridomyrmex purpureus form viridiaeneus Viehmeyer (Hymenoptera: Formicidae). J. Aust. Entomol. Soc. 13: 247-248 (page 247, Subspecies of purpureus)
• Heterick, B.E. & Shattuck, S.O. 2011. Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae). Zootaxa 2845: 1-175.
• Heterick, B.E. 2021. A guide to the ants of Western Australia. Part I: Systematics. Records of the Western Australian Museum, Supplement 86, 1-245 (doi:10.18195/issn.0313-122x.86.2021.001-245).
• Heterick, B.E. 2022. A guide to the ants of Western Australia. Part II: Distribution and biology. Records of the Western Australian Museum, supplement 86: 247-510 (doi:10.18195/issn.0313-122x.86.2022.247-510).
• Shattuck, S. O. 1993a. Revision of the Iridomyrmex purpureus species-group (Hymenoptera: Formicidae). Invertebr. Taxon. 7: 113-149 (page 142, Raised to species)
• Shattuck, S. O. 1994. Taxonomic catalog of the ant subfamilies Aneuretinae and Dolichoderinae (Hymenoptera: Formicidae). Univ. Calif. Publ. Entomol. 112:i-xix, 1-241. (page 113, see also)
• Taylor, R. W.; Brown, D. R. 1985. Formicoidea. Zool. Cat. Aust. 2:1- 149: 1-149, 30 (page 102, Subspecies of purpureus)
• Viehmeyer, H. 1914b. Neue und unvollständig bekannte Ameisen der alten Welt. Archiv für Naturgeschichte 79 (A.12) (1913): 24-60. (page 41, worker described)
• Wheeler, G. C.; Wheeler, J. 1974b [1973]. Ant larvae of the subfamily Dolichoderinae: second supplement (Hymenoptera: Formicidae). Pan-Pac. Entomol. 49: 396-401 (page 400, larva described)
• Wheeler, G. C.; Wheeler, J. 1974b [1973]. Ant larvae of the subfamily Dolichoderinae: second supplement (Hymenoptera: Formicidae). Pan-Pac. Entomol. 49: 396-401 (page 400, Raised to species)
• Wheeler, W. M. 1915h. Hymenoptera. [In "Scientific notes on an expedition into the north-western regions of South Australia".]. Trans. R. Soc. S. Aust. 39: 805-823 (page 811, queen described)

References based on Global Ant Biodiversity Informatics

• CSIRO Collection
• Gunawardene N. R. and J. D. Majer. 2005. The effect of fire on ant assemblages in the Gibson Desert Nature Reserve, Western Australia. Journal of Arid Environments 63: 725-739.
• Heterick B. E., B. Durrant, and N. R. Gunawardene. 2010. The ant fauna of the Pilbara Bioregion, Western Australia. Records of the Western Australian Museum, Supplement 78: 157-167.
• Heterick B. E., and S. Shattuck. 2011. Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae). Zootaxa 2845: 1-174.
• Read J. L., and A. N. Andersen. 2000. The value of ants as early warning bioindicators: responses to pulsed cattle grazing at an Australian arid zone locality. Journal of Arid Environments 45: 231-251.
• Shattuck S. O. 1993. Revision of the Iridomyrmex purpureus species-group (Hymenoptera: Formicidae). Invertebrate Taxonomy 7: 113-149.