Atta (ant)
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| queen of A. colombica | |
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| Genus: | Atta Fabricius, 1805
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Atta is a genus of New World ants of the subfamily Myrmicinae. It contains at least 16 known species.
Leaf-cutter ants are relatively large, rusty red or brown colour and have a spiny body and long legs. There are three main castes within a nest: the queen, worker and soldier.[1] Only the queens have wings and these ants are also known as 'reproductives' or 'swarmers'. Although most of the ants in the nest are female, only the queens produce eggs. Queens are usually over 20mm long.
Overview
Ants of the genus Atta are leafcutter ants that comprise one of the two genera of leafcutting ants within the tribe Attini, along with Acromyrmex.
Atta is one of the most spectacular of the attines, with colonies that can comprise in excess of one million individuals.[citation needed]
Atta exhibits a high degree of polymorphism, with four castes being present in established colonies: minims (or 'garden ants'), minors, mediae, and majors (also called soldiers or dinergates).
The high degree of polymorphism in this genus is also suggestive of its high degree of advancement. Every caste has a specific function, and some remarkably advanced phenomena have been observed in respect of Atta species. An example of such is the behaviour of the minim ants, which climb on the cut sections of leaf whilst they are carried back to the nest by the media workers to protect the latter from a particular species of phorid fly that parasitises the leaf-carrying caste. While hitchhiking, the minims also work to decontaminate the fragment before it arrives at the nest and feed on the sap of the leaf.[2] That the minims behave in this way demonstrates the highly derived character of the species.
Like Acromyrmex, Atta subsists mostly on a particular species of fungus which it cultivates on a medium of masticated leaf tissue. This is the sole food of the queen and other colony members that remain in the nest. The media workers also gain subsistence from plant sap they ingest whilst physically cutting out sections of leaf from a variety of plants.[3]
Before leaving their parent colonies, winged females take a small section of fungus into their bucchal pouches and it is with this that the subsequently wingless queens 'seed' the fungus gardens of incipient colonies, cutting and collecting the first few sections of leaf themselves.
Atta has evolved to change foodplant constantly, preventing a colony from completely stripping off leaves and thereby killing trees, thus avoiding negative biological feedback on account of their sheer numbers.[citation needed] However, this does not diminish the huge quantities of foliage they harvest; Atta is estimated for being responsible for the decomposition of 20% of all leaves in South America.[citation needed] Consequently, the genus is considered a major agricultural pest species in areas where its range coincides with arable farming activity.
Species
- Atta bisphaerica (Borgmeier, T., 1939)
- Atta capiguara (Wild, A. L., 2007)
- Atta cephalotes (Linnaeus, 1758)
- Atta colombica (Guérin-Méneville, 1844)
- Atta cubana (Fontenla Rizo, 1995)
- Atta goiana (Gonçalves, 1942)
- Atta insularis (Guérin-Méneville, 1845)
- Atta laevigata (F. Smith, 1858) (Colombia south to Paraguay)
- Atta mexicana (F. Smith, 1858)
- Atta opaciceps (Borgmeier, 1939)
- Atta robusta (Borgmeier, 1939)
- Atta saltensis (Forel, 1913)
- Atta sexdens (Linnaeus, 1758)
- Atta texana (Buckley, 1860) - Texas Leafcutter Ant (eastern Texas and western Louisiana in the United States, northeastern Mexico)
- Atta undet
- Atta vollenweideri (Forel, 1893)
In popular culture
In Pixar's 1998 film A Bug's Life, the colony's princess is named Atta.
Uses
As food
Atta species are considered a delicacy by the Guanes tribe and have a nutty bacon-like flavor.
See also
- Acromyrmex, the other genus of leafcutter ants
- List of leafcutter ants
- Atta sexdens
- Atta texana
- List of ant genera (alphabetical)
References
- ^ "Natural History Museum".
- ^ Vieira-Neto, E. H. M., F. M. Mundim, and H. L. Vasconcelos. 2006. Hitchhiking behaviour in leafcutter ants: An experimental evaluation of three hypotheses. Insectes Sociaux 53:326-332.
- ^ Littledyke, M., and J. M. Cherrett. 1976. Direct ingestion of plant sap from cut leaves by leafcutting ants Atta cephalotes (L.) and Acromyrmex octospinosus. Bulletin of Entomological Research 66:205-217.