Southern Meat Ant

In general, meat ants are medium to large in size, measuring 6–12 mm (0.24–0.47 in), and can be easily recognised by their dark-bluish body and red head. Generally, their heads and pronotums share similar colours and are lighter than the mesothorax (the middle of the three segments in the thorax) and the propodeum (the first abdominal segment), which are reddish brown. However, the head may sometimes be lighter, and the pronotum and mesothorax may share similar colours. The mesosomal setae (as in hair found on the mesosoma) are dark and sometimes translucent. The iridescence between the compound eyes and the lateral portion of the head ranges from slightly purple to strong and dark purple. The colour of the legs and coxae (the basal segment of the insect leg, which attaches to the body) are darker than the mesothorax, and the petiole (narrow waist) is reddish brown and also darker than the mesothorax. The lateral portion of the second gastral tergite (a dorsal segment other than the head) is shiny, and the iridescence varies among workers, from green or blue to plain green and purple. The soft hairs on the head are frequent around the occipital margin, and around the mandibular insertion, three to eight pale setae are usually seen. The soft hairs are also common around the first gastral tergite. Examined specimens show no known ocelli. Erect setae on the pronotum are abundant. …

The meat ant is one of the best-known species of ant endemic to Australia; it has an enormous geographical range, covering at least one-third of the continent. Its range spans 4,000 kilometres (2,500 mi) from east to west, and 3,000 kilometres (1,900 mi) from north to south. This extensive range has allowed the meat ant to form large nesting grounds in areas where no development has occurred, and large amounts of gravel and open space have led to an abundant supply of materials (i.e. pebbles and dead pieces of vegetation) used to construct nests. The ant is particularly dominant and frequently seen across the coastal and inland regions of southeastern Australia. Based on examined material, meat ants are widespread throughout New South Wales, the Australian Capital Territory and Victoria. In Queensland, they are frequently encountered in the eastern regions, whereas their abundance is limited around the north and central parts. The ants are common in the southwestern regions of Western Australia, though not in the north. However, the Division of Entomology of the CSIRO states that the ant's presence in the state has not been verified. Most specimens collected in South Australia are from the south-east, but some populations are known in the north-west and northeast regions of the state. …

Like other Iridomyrmex species, the meat ant is an omnivore, retrieving food sources from various insects it tends, including caterpillars and various sorts of butterflies, particularly the larvae of the Waterhouse's hairstreak (Jalmenus lithochroa). Meat ants usually feed on honeydew from sap-sucking insects, flower nectar, sugar and other sweet substances. In captive colonies, workers prefer to consume small pieces of grapes rather than honey solutions and other sweet foods. These ants prey on various insects and animals, collecting both live and dead invertebrates and acquire meat from dead vertebrates. Insects the meat ants prey on include giant lacewings, which they swarm up trees to kill, the butterfly genoveva azure Ogyris genoveva, Indian mealmoths, almond moths, the Western Australian jarrah leafminer and the larvae of the wasp Trichogramma. Large and developed larvae of the cabbage butterfly (Pieris rapae) are attacked more effectively by meat ant workers than those of other Iridomyrmex species. On sandy beaches, this species is observed preying on the polychaete annelid worm, Armandia intermedia, causing high mortality rates on them (rates of 30 percent). These ants will feed on a number of dead or alive animals, including metamorphic crucifix toads, snakes, lizards, and birds. On some occasions, swarms of workers have been found on dead foxes. …

The specific epithet of the meat ant, purpureus, derives from Latin, in which it means "purple", "purple-coloured" or "dark-red", referencing the coloured appearance of the ant. In classical Latin, purpureus primarily translated to "dyed purple", while the word purpura, used by Smith for the meat ant (Formica purpura), translates to "purpled-dyed cloth". The generic name, Iridomyrmex, translates to "rainbow ants" from Ancient Greek, another reference which points to its appearance. This, in particular, is due to its blue-green iridescence colour. It is a compound of two Ancient Greek words – iris, meaning "rainbow", and myrmex, that means "ant". The ant is commonly known as the meat ant because of its habit of stripping the meat off dead vertebrates. Alternative names include the gravel ant, Greenslade's meat ant, meat-eater ant, mound ant, or southern meat ant. The name "southern meat ant" is due to its extreme abundance in the southern regions of Australia.