Iridomyrmex

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Iridomyrmex
Meat eater ant feeding on honey02.jpg
Meat ant (I. purpureus)
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dolichoderinae
Tribe: Leptomyrmecini
Genus: Iridomyrmex
Mayr, 1862
Type species
Formica detecta
Diversity[1]
c. 79 extant species
5 fossil species

Iridomyrmex, or rainbow ants (referring to their blue-green iridescent sheen) is a genus of ants in the subfamily Dolichoderinae.[1] There are 79 extant species in this genus and they range from India to China to Australia and New Caledonia.

Description[edit]

Unlike other genera in Dolichoderinae, Iridomyrmex ants have the front margin of the clypeus above the mandibles highly modified with convex areas towards the sides and a central projection, which varies from strongly to weakly developed. The compound eyes are relatively high on the head and away from the mandibles.

Behaviour[edit]

Meat ants swarming

Iridomyrmex ants are generally aggressive to other ants. They form large nests (from several hundred to over 300,000 workers), which limits the number of competing nests that can be formed in a given area. Often, the only neighbouring ant species that can co-exist are those that are of different size or those that forage for food at different times, thus limiting contact with the Iridomyrmex ants. They can be territorial even with ants of their own species but from different nests.

Nests may be above or below ground, with some species such as I. conifer alternating between the two. Meat ants (I. purpureus) are known to create "super-colonies" of many small nests that are connected together, reaching as large as 650 metres in length.

Feeding[edit]

Iridomyrmex ants are generally scavengers. Workers of some species will form "highways" to food sources, while workers of other species forage singly. Iridomyrmex are particularly attracted to seeds with elaiosomes. They will collect these seeds and remove the elaiosomes, discarding the seeds afterwards. The seedlings that sprout from these seeds benefit from the aggressiveness of the Iridomyrmex ants, giving them a better chance of survival.

Caterpillars of certain butterfly species have a symbiotic relationship with Iridomyrmex ants. They produce secretions that the ants will feed on. In extreme cases, the ants will carry the caterpillar back to their nests where they will protect it. These ants may also tend to aphids and coccids, collecting nectar when possible.

Predators[edit]

Some invertebrate species specialise in predation of Iridomyrmex ants. There are species of spiders that can detect the ants' chemical communications and selectively target injured members. Ground beetles also have been known to create burrows near ant nests and prey on passing workers. The Australian lizard, thorny devil is also a major predator.

Species[edit]

Queen digging a hole

See also[edit]

References[edit]

  1. ^ a b "Genus: Iridomyrmex". antweb.org. AntWeb. Retrieved 14 October 2013.