Iridomyrmex purpureus

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Iridomyrmex purpureus
Iridomyrmex purpureus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dolichoderinae
Tribe: Leptomyrmecini
Genus: Iridomyrmex
Species: I. purpureus
Binomial name
Iridomyrmex purpureus
(Smith, F., 1858)

Iridomyrmex purpureus ANIC32-008690 side 20-Antwiki.jpg

Iridomyrmex purpureus ANIC32-008690 top 20-Antwiki.jpg


This species forms large pebble mounds with multiple nest holes. Wherever it occurs, I. purpureus is extremely pugnacious, and workers will pour out of entrance holes to attack any person or other creature that disturbs their nest. Workers forage on the ground and will also ascend trees in search of nectar and honeydew.

At a Glance • Polygynous  

Photo Gallery

  • Workers at their nest entrance. Photo by Steve Shattuck
  • Iridomyrmex purpureus foraging worker from Kalamunda, Perth, Western Australia. Photo by Farhan Bokhari, 29 April 2011.
  • Iridomyrmex purpureus dealate queen, just after her nuptual flight, constructing a nest founding chamber. Once complete, the queen will enter the chamber, seal the entrance, lay her first batch of eggs, and patiently tend to them until they hatch. She will not feed until her daughters emerge as adult workers and start foraging. Brimbank Park, Melbourne, Victoria, Australia. Photo by Jordan Dean.


Physically, I. purpureus workers are difficult to distinguish from Iridomyrmex lividus, and these two species form a complex, along with the much more localised Iridomyrmex spadius, that can be distinguished from other meat ant complexes by the shape of the pronotum when seen in profile.

Apart from the variation in colour used to separate I. purpureus and its junior synonym, I. greensladei, I. purpureus populations exhibit an unsettling polymorphism in other respects, some in the extreme south-west of Western Australia referable to I. greensladei having erect setae on the genae while those outside that region have glabrous genae. Shattuck (1993a) found this pattern to be likely clinal. The colour of the erect setae found on all parts of the body, and to some degree the iridescence, can also vary: I. purpureus with pale setae are confined to the extreme south coast of Western Australia, compared with a much broader distribution for those populations possessing the normal, blackish setae. Again, Shattuck (1993a) could not separate the pale setae form from remaining populations of I. ‘greensladei’ when other characters were considered. A tendency to pale greenish-blue to yellowish-green iridescence is also found in specimens from the Western Australian wheatbelt and goldfields, particularly on the humeri and the frons, but this is a more subtle character than the other two mentioned, and there is no hard-and-fast distinction between these and other members of the taxon. The difference in colour is much less marked, for example, than colour differences between Iridomyrmex viridiaeneus (also found in drier parts of the south-west) and all samples of I. purpureus seen. Other variants mentioned by Shattuck (1993a) include workers with reduced appressed pubescence on the first gastral tergite (found in South Australia and the Northern Territory).

Keys including this Species


Latitudinal Distribution Pattern

Latitudinal Range: -10.743702° to -37.98332977°.

Tropical South

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.


Moulds (2006) - Iridomyrmex purpureus workers have been observed entering a mine, collecting fresh bat guano and carrying it back to their nest. Guano is known to be eaten directly by many guanobitic and guanophilic invertebrates as a high nitrate food, or, more commonly the more for its readily digested glycogen rich bacteria and fungus.

Brooker (2007) - On the afternoon of 4 October 2004, I watched a pair of Chestnut-rumped Thornbills Acanthiza uropygialis in the vicinity of a Wheatbelt Wandoo Eucalyptus capillosa, that contained a hollow in which the birds had previously nested. For 30 minutes the pair fluttered to the trunk of the wandoo and pecked at meat ants that were moving on it. After each attack, an ant fell to the ground and I surmised that the birds were defending their eggs or nestlings. However, the nest was not occupied. A more likely explanation of this unusual behaviour could be that the thornbills were robbing the ants of the small white items (perhaps lerps) they were carrying. Splendid Fairy-wrens Malurus splendens will often rob meat ants moving on their trails and mounds (Rowley and Russell 1997 in Fairy-wrens and Grasswrens, Oxford University Press: Oxford; and personal observation), but I have not previously seen this foraging technique undertaken arboreally or by thornbills.

Hölldobler & Carlin (1985) - In Iridomyrmex purpureus, most new colonies are founded by single queens, following the nuptial flight in the spring month of October. Sixty-five of 72 newly founded nests excavated near Canberra contained a single queen, six contained two queens, and one contained three queens. As the nearby inseminated queens scurry over the ground and then start to dig a burrow in the soil, they are attacked by many enemies. Greaves and Hughes (1974) reported losses of 80 percent or higher from ground-feeding birds alone. Many other queens are killed by hostile workers of their own species when they stray too near the established colonies. But, surprisingly, other queens succeed in digging their nest chambers in the immediate vicinity of mature Iridomyrmex purpureus. Not only are most of these females tolerated by the resident workers, they are often attended and protected. The workers even help them dig the chambers (see Figure 6-1). Such actions are likely to protect the foundresses from hostile ants, birds, and other predators. Meat ant workers are extremely aggressive, biting enemies and spraying them with poisonous secretions from their pygidial glands. Hölldobler and Carlin believe that the queens protected in this manner are the ones fortunate enough to settle near their natal nests, so that the foundresses are also likely to be absorbed into the mother colonies to become supernumerary queens. Thus variation in queen numbers appears to be due at least in part to the vicissitudes of foundress association and tolerance by neighboring mature colonies.

Flight Period

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Source: Hölldobler & Carlin, 1985.

Life History Traits

  • Queen number: polygynous (Halliday, 1983; Frumhoff & Ward, 1992)
  • Queen type: winged (Halliday, 1983; Frumhoff & Ward, 1992) (queenless worker reproduction)
  • Queen mating frequency: single (Halliday, 1983; Frumhoff & Ward, 1992)



Images from AntWeb

Iridomyrmex purpureus casent0010657 head 1.jpgIridomyrmex purpureus casent0010657 profile 1.jpgIridomyrmex purpureus casent0010657 dorsal 1.jpgIridomyrmex purpureus casent0010657 label 1.jpg
Worker. Specimen code casent0010657. Photographer April Nobile, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.
Iridomyrmex greensladei casent0172039 head 1.jpgIridomyrmex greensladei casent0172039 profile 1.jpgIridomyrmex greensladei casent0172039 dorsal 1.jpgIridomyrmex greensladei casent0172039 label 1.jpg
Holotype of Iridomyrmex purpureusWorker. Specimen code casent0172039. Photographer April Nobile, uploaded by California Academy of Sciences. Owned by ANIC, Canberra, Australia.
Iridomyrmex purpureus casent0006108 head 1.jpgIridomyrmex purpureus casent0006108 profile 1.jpgIridomyrmex purpureus casent0006108 dorsal 1.jpgIridomyrmex purpureus casent0006108 label 1.jpg
Worker. Specimen code casent0006108. Photographer April Nobile, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.


Images from AntWeb

Iridomyrmex greensladei casent0172040 head 1.jpgIridomyrmex greensladei casent0172040 profile 1.jpgIridomyrmex greensladei casent0172040 profile 2.jpgIridomyrmex greensladei casent0172040 dorsal 1.jpgIridomyrmex greensladei casent0172040 label 1.jpg
Paratype of Iridomyrmex purpureusMale (alate). Specimen code casent0172040. Photographer April Nobile, uploaded by California Academy of Sciences. Owned by ANIC, Canberra, Australia.


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

  • aeneum. Liometopum aeneum Mayr, 1862: 704 (q.) AUSTRALIA. Junior synonym of purpureus: Mayr, 1876: 81.
  • castrae. Iridomyrmex detectus var. castrae Viehmeyer, 1925a: 31 (w.) AUSTRALIA. Subspecies of purpureus: Taylor & Brown, D.R. 1985: 102. Junior synonym of purpureus: Shattuck, 1993a: 128.
  • detecta. Formica detecta Smith, F. 1858b: 36 (q.) AUSTRALIA. Wheeler, G.C. & Wheeler, J. 1974b: 398 (l.); Crozier, 1968a: 25 (k.). Combination in Iridomyrmex: Dalla Torre, 1893: 168. Junior synonym of purpureus: Lowne, 1865a: 275; Mayr, 1876: 81; Taylor & Brown, D.R. 1985: 102.
  • greensladei. Iridomyrmex greensladei Shattuck, 1993a: 122, fig. 11 (w.q.m.) AUSTRALIA. Junior synonym of purpureus: Heterick & Shattuck, 2011: 124.
  • horni. Camponotus horni Kirby, W.F. 1896: 205 (w., not q.) AUSTRALIA. Junior synonym of purpureus: Clark, 1930c: 20. See also: Shattuck, 1993a: 128.
  • purpureus. Formica purpurea Smith, F. 1858b: 40 (w.) AUSTRALIA. Lowne, 1865a: 275 (m.); Imai, Crozier & Taylor, 1977: 345 (k.). Combination in Iridomyrmex: Mayr, 1862: 702. Senior synonym of detecta: Lowne, 1865a: 275; of smithii: Mayr, 1870b: 955; of aeneum: Mayr, 1876: 81; of horni: Clark, 1930c: 20; Shattuck, 1993a: 128; of castrae: Shattuck, 1993a: 128; of greensladei: Heterick & Shattuck, 2011: 124. See also: Greaves, 1971: 15; Shattuck, 1993a: 128; Shattuck, 1994: 109.
  • smithii. Formica smithii Lowne, 1865a: 276 (w.) AUSTRALIA. Junior synonym of purpureus: Mayr, 1870b: 955; Taylor & Brown, D.R. 1985: 102.

Type Material

Taxonomic Notes

Iridomyrmex greensladei (Shattuck, 1993a) is supposedly separated from I. purpureus by the hue of its head and pronotum, which are concolorous with the rest of the mesosoma (lighter than the rest of the mesosoma in I. purpureus). The two nominal species were regarded as nonsympatric by Shattuck (his figures 11 and 13 form a nice symmetry). Additional evidence adducing that I. greensladei and I. purpureus were separate came from Halliday (1979 and 1981) who examined the enzymes esterase and amylase within the I. purpureus species-group. That researcher found differing amylase allele frequencies that suggested that I. purpureus and I. greensladei clustered into two separate groups (along with other meat ant forms). However, research during the present study has failed to recover a clear distinction in colour between a number of eastern and western populations of meat ants formerly categorised as ‘greensladei’ and ‘purpureus’ , namely, some Western Australian populations have a head that is paler than the mesosoma, and vice-versa for some eastern states populations. Moreover, much worker material is indeterminate as to colour. Unpublished mitochondrial DNA (using the CO 1 gene) has also failed to authoritatively distinguish western and eastern populations of ‘greensladei’ and ‘purpureus’; indeed, the distance between the terminals falls well within what is normally regarded as acceptable for populations of the same species (<< 0.1 substitutions/site). The two nominal species also strongly overlap in regards to a number of morphometric measurements.

The work of Halliday notwithstanding, the evidence thus suggests that the common reddish meat ants of eastern and western Australia are conspecific. However, there is a caveat: the form found in the Yorke Peninsula in South Australia, and identified by Greenslade (1987) as ‘small purple’ or SP, was intended to be the same as I. greensladei. Although these ants are morphologically indistinguishable from some Western Australian I. greensladei and many I. purpureus (both of which have multiple entrance mound nests), they supposedly have a single nest entrance (Greenslade, 1987). However, Shattuck chose workers from Israelite Bay, Western Australia, 1000 km west of the Yorke Peninsula, for his I. greensladei holotype and paratypes, respectively. This means that the form SP found in the Yorke Peninsula (which has not thus far been subject to CO 1 analysis) may yet prove to be genetically distinct, albeit morphologically cryptic. The decision made here is to treat the currently existing taxa represented by the eastern I. purpureus and the Western Australian ‘I. greensladei’ as conspecific, with the latter name falling into synonymy: potentially, a new name could be erected if future research revealed the Yorke Peninsula ants were indeed a separate species.


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 present on sides of head in full-face view, or 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 3 x its diameter, or 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. 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 protuberant, or smoothly and evenly convex; placement of propodeal spiracle 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; 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 absent. Colour of head and often pronotum orange to brick-red, mesonotum and propodeum lighter than, concolorous with or darker than the head, gaster brown to black, legs orange to brown, foreparts with bluish, pink, pale greenish-yellow or purple iridescence, gaster with greenish, bluish or purple iridescence. Colour of erect setae brown.

Measurements. Worker (n = 84)—CI 89–103; EI 17–22; EL 0.33–0.42; EW 0.18–0.26; HL 1.69–2.3 1; HW 1.5 1–2.29; ML 0.76–1.26; PpH 0.21–0.44; PpL 0.83–1.28; SI 86–104; SL 1.57–2.05.


  • n = 9, 2n = 18 (Australia) (Crozier, 1968a; Crozier, 1968c; Imai et al., 1977) (Iridomyrmex detectus in Crozier 1968a).

Worker Morphology

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  • Caste: weakly polymorphic


References based on Global Ant Biodiversity Informatics

  • Andersen A. N., B. A. Myers, and K. M. Buckingham. 1991. The ant fauna of a Mallee outlier near Melton, Victoria. Proceedings of the Royal Society of Victoria 103(1): 1-6.
  • Andersen A. N., and A. V. Spain. 1996. The ant fauna of the Bowen Basin, in the Semi-arid Tropics of Central Queensland (Hymenoptera: Formicidae). Australian Journal of Entomology 35: 213-221.
  • CSIRO Collection
  • Chong C-S., L. J. Thomson, and A. A. Hoffmann. 2011. High diversity of ants in Australian vineyards. Australian Journal of Entomology 50: 7-21.
  • Clark J. 1929. Results of a collecting trip to the Cann River, East Gippsland. Victorian Naturalist (Melbourne) 46: 115-123.
  • Emery C. 1914. Formiche d'Australia e di Samoa raccolte dal Prof. Silvestri nel 1913. Bollettino del Laboratorio di Zoologia Generale e Agraria della Reale Scuola Superiore d'Agricoltura. Portici 8: 179-186.
  • Emery, C.. "Catalogo delle formiche esistenti nelle collezioni del Museo Civico di Genova. Parte terza. Formiche della regione Indo-Malese e dell'Australia." Annali del Museo Civico di Storia Naturale Giacomo Doria (Genova) (2) 4, no. 24 (1887): 209-258.
  • Forel A. 1893. Nouvelles fourmis d'Australie et des Canaries. Ann. Soc. Entomol. Belg. 37: 454-466.
  • Forel A. 1902. Fourmis nouvelles d'Australie. Rev. Suisse Zool. 10: 405-548.
  • Forel A. 1915. Results of Dr. E. Mjöbergs Swedish Scientific Expeditions to Australia 1910-13. 2. Ameisen. Ark. Zool. 9(16): 1-119
  • Heterick B. E. 2009. A guide to the ants of south-western Australia. Records of the Western Australian Museum Supplement 76: 1-206. 
  • Heterick B. E., and S. Shattuck. 2011. Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae). Zootaxa 2845: 1-174.
  • Majer J. D., and O. G. Nichols. 1998. Long-term recolonization patterns of ants in Western Australian rehabilitated bauxite mines with reference to their use as indicators of restoration success. Journal of Applied Ecology 35: 161-182.
  • Major R.E., D. Smith, G. Cassis, M. Gray, and D. J. Colgan. 1999. Are roadside strips important resrvoirs of invertebrate diversity, A comparison of the ant and beetle faunas of roadside strips and large remnant woodlands. Australian Journal of Zoology 47: 611-624.
  • Osunkoya O. O., C. Polo, and A. N. Andersen. 2011. Invasion impacts on biodiversity: response of ant communities to infestation by cat's claw creeper vine, Macfadyena unguis-cati (Bignoniaceae) in subtropical Australia. Biol. Invasions 13: 2289-2302.
  • 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.
  • Shattuck S. O. 1994. Taxonomic catalog of the ant subfamilies Aneuretinae and Dolichoderinae (Hymenoptera: Formicidae). University of California Publications in Entomology 112: i-xix, 1-241.
  • Steinbauer M. J., and R. Peveling. 2011. The impact of the locust control insecticide fipronil on termites and ants in two contrasting habitats in northern Australia. Crop Protection 30(7): 814-825.
  • Stitz H. 1911. Australische Ameisen. (Neu-Guinea und Salomons-Inseln, Festland, Neu-Seeland). Sitzungsberichte der Gesellschaft Naturforschender Freunde zu Berlin 1911: 351-381.
  • Taylor R. W. 1987. A checklist of the ants of Australia, New Caledonia and New Zealand (Hymenoptera: Formicidae). CSIRO (Commonwealth Scientific and Industrial Research Organization) Division of Entomology Report 41: 1-92.