Atta (genus)
| Atta | ||||||||
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Atta cephalotes cutting leaves, Wilhelma , Stuttgart |
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| Scientific name | ||||||||
| Atta | ||||||||
| Fabricius 1805 |
Atta is a genus of ants which, due to its behavior, is one of the so-called leaf cutter ants .
description
The species of the genus Atta are reddish-brown ants. Their mandibles are greatly enlarged due to their special way of life. Like all knot ants, they have a postpetiolus in addition to the petiolus. This means that her waist is bipartite. The size of the individual individuals varies greatly within the species: while small workers (minors) are only 1.5 millimeters long, the queen with her abdomen, which is vastly inflated to lay eggs, can even reach lengths of up to 25 millimeters.
Way of life
The genus belongs to the leaf cutter ants. This means that with their mandibles, which have been greatly enlarged for this purpose, they harvest leaves, blades of grass and other plants, carry them into their burrows and grow mushrooms on this plant material. These mushrooms are the ants' only food, so they are carefully tended and protected by the workers.
The Atta form in addition to the African Dorylus the largest known insect colonies with up to 5 million members. Despite the enormous size, a colony only ever includes one queen, which means that the people perish after the queen's death. The 5 million colony members are divided into up to 20 castes, each of which has its own task.
Hölldobler and Wilson describe the leaf cutter ants of the Atta genus in their book The Superorganism as the most highly developed ants and use the sophisticated communication by means of pheromones, the meticulously coordinated cooperation, thanks to which mushroom cultivation is only possible, and the construction of highly complex underground chamber nests as justifications. on.
Since Atta have no poison glands and their sting has receded, the nest is defended with the help of the strongly developed mandibles. As soon as an enemy approaches, touches or even grabs the nest, dozens of workers immediately bite into it. Researchers feel that too. The defense applies especially to other Atta , as colonies whose fungus died often attack other nests in order to plunder the mushroom stocks there.
The nests are extremely complex. There are chambers for the rearing of the brood, which are mostly close to the surface, the queen's chamber, which is centrally located to offer the mother of the colony the best possible protection, and there are waste chambers in which the workers hold dead mushrooms and dead ones Throw nest mates. The colony heats its nest with the energy generated during rotting. There is also a system of channels and tubes through which stale air can escape and fresh air can be drawn in.
Systematics
External systematics The ant genus belongs to the subfamily of the knot ants.
Internal system
- Atta bisphaerica
- Atta capiguara
- Atta cephalotes
- Atta colombica
- Atta cubana
- Atta goiana
- Atta insularis
- Atta laevigata
- Atta mexicana
- Atta opaciceps
- Atta pilosa
- Atta robusta
- Atta saltensis
- Atta sexdens
- Atta tardigrada
- Atta texana
- Atta vollweideri
swell
- Bert Hölldobler, Edward O. Wilson: The superorganism
- Bert Hölldobler, Edward O. Wilson: The Ants