Atta laevigata
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Atta laevigata |
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Atta laevigata is a species of leaf cutter ants from the genus Atta . It iswidespreadin South America and is one of the most common species in its genus.
features
Leaf-cutter ants of the Atta genus attract attention at first glance with three pairs of more or less long teeth that sit behind the eyes, on the pronotum and on the mesonotum . They are easily distinguishable from the sister genus Acromyrmex by their smooth abdomen. An extreme size polymorphism of the workers is characteristic of all species, with the large forms, called soldiers, merging with the smallest in a uniform form, not divided into sub-castes. The sex animals are strikingly large in relation to the workers. Small workers (and queens) are usually not identifiable down to the species, especially Atta vollweideri and some related species (subgenus Epiatta ) are very similar. The big workers (soldiers) are quite characteristic.
In the species Atta laevigata , the workers reach lengths between 4 and 16 millimeters, queens up to 22 millimeters. The animals are uniformly reddish brown to chestnut brown in color, rarely a bit darker. The largest workers (majores or soldiers) are larger than most related species (head width 6 to 7.7 millimeters). Striking and characteristic of the other large species is the very shiny, as if polished head. Males can be recognized by the structure of the mating organs and the shape of the subgenital plate. In the species, the teeth (thorns) behind the eyes and on the middle section (or mesosoma) are quite short in the majors, but long and pointed in the smaller workers.
distribution and habitat
The species lives in South America, it has a large distribution area in the north of the continent, east of the Andes. Evidence is available from Colombia, Venezuela, Guyana, Brazil (up to the Atlantic coast), Bolivia and Paraguay. It lives in the tropical rainforests of the lowlands up to about 1000 meters above sea level, and also in savannah landscapes such as the cerrado .
Way of life and ecology
As is typical for leaf cutter ants of the Attini tribe , this species also primarily harvests green, fresh plant parts, which it enters into its underground burrow and then cultivates a mushroom, the fruiting of which is its only source of protein. The necessary carbohydrates are obtained from the juices of the chewed leaves / grasses as well as fruits and flowers.
The colony is founded by a single, winged queen ( monogynous and claustral ) in spring. For the establishment of a colony, open, sparsely vegetated soil away from tree trunks is preferred, very much on unpaved roadsides, which can thus increase their local density. The nest building begins with a vertical passage with a nest chamber about 20 to 30 centimeters deep. Here the queen founds the first mushroom garden from the mycelia she brought with her from the mother-colony's mushroom and pulls in the first workers. The reserves from the particularly large body and nutrients from the breakdown of the flight muscles benefit her. Adult colonies can later reach enormous sizes and comprise up to three million workers. They then consist of a nest mound that has numerous entrances in different directions. From the entrances extend the strictly organized streets typical of the Atta genus , up to 200 m long and leading to plants, parts of which (especially leaves) are harvested and carried into the mushroom chambers.
Atta laevigata is territorial and defends a food territory against ants of the same and other species. The territory is marked with a pheromone , which is formed by Dufour's glands and distributed by dabbing on the guests. The pheromone is also used for orientation. There can be real battles between neighboring nests with thousands of participants that last for several days. The mandibles are used as weapons. The animals also defend themselves against nest disturbances (by vertebrates). Smaller workers are recruited for defense against other ants, while larger workers are preferred against vertebrates.
By harvesting parts of the plant, leaf cutter ants are key ecological species in the Neotropic . They are the most important herbivores here and in this function they are more important than all herbivorous vertebrates living here. In a study in the tree savannah of the Cerrado, Atta laevigata (there just under 5 nests per hectare) consumed between 13 and 17 percent of the leaf biomass. Their ecological importance does not reach that of the ungulates in the savannahs of Africa, but exceeds that of all leaf-eaters taken together in the forests of the temperate latitudes by orders of magnitude. In the study, Atta laevigata recorded not only green leaves (around two thirds of the amount of food) but also dead leaf litter, twigs, flowers, fruits and grasses. Since they use the leaves of cultivated plants in the same way, they are important agricultural harmful organisms in their homeland. All leaf cutter ants taken together (the species are rarely differentiated) are said to cause annual damage of 130 million dollars in the Brazilian state of São Paulo alone .
The species of fungus cultivated by Atta laevigata on the registered leaves is the wild, non-viable Egerling umbrella Leucoagaricus gongylophorus . This type of mushroom is probably identical in all Atta species. Although there is some evidence of coevolution between fungal trunks and ant species in leafcutter ants, apparently horizontal exchanges between them are not uncommon.
Taxonomy and systematics
The first description by Smith was made with three workers caught by Bates at Santarém , Smith originally classified the ant in the genus Oecodoma , which is now a synonym for Atta . A clear assessment of whether the Atta laevigata is a separate species or a variety could not be answered with certainty by Smith without observing living ants, but the bare head and smooth stomach area indicated for him a species of its own.
According to molecular studies using DNA sequences, Atta laevigata belongs to a species group with species such as Atta vollweideri , Atta capiguara , Atta bisphaerica and the like. a. which, according to morphological criteria, had previously been described as the subgenus Epiatta . This sub-genus is currently mostly no longer recognized and was later abandoned by the person who first described it. The monophyly of the species Atta laevigata compared to the related species could neither be confirmed nor refuted due to an insufficient database.
The Atta silvai described from the Brazilian state of Bahia is synonymous with Atta laevigata .
Use by humans as food insects
Ants of the species Atta laevigata are eaten as food insects in Colombia . “Hormigas Culonas” is a culinary specialty of the Santander region . For this purpose, females ( queens ) are used, which have a greatly enlarged abdomen . The animals are fried. The dish is considered an aphrodisiac .
Individual evidence
- ↑ Thomas Borgmeier: Revision of the genus Atta Fabricius (Hymenoptera, Formicidae). In: Studia Entomologica. vol. 2, fasc. 1-4, 1959, pp. 321-390.
- ↑ Heraldo L. Vasconcelos, Ernane HM Vieira-Neto, Fabiane M. Mundim: Roads Alter the Colonization Dynamics of a Keystone Herbivore in Neotropical Savannas. In: Biotropica. 38 (5), 2006, pp. 661-665. doi: 10.1111 / j.1744-7429.2006.00180.x
- ↑ Alex C. Mintzer: Colony Foundation in Leafcutting Ants: The Perils of Polygyny in Atta Laevigata (Hymenoptera: Formicidae). In: Psyche. 98 (1), 1990, pp. 1-4.
- ↑ A. salts, P. Nagnan, F. Tellier, K. Jaffe: Leaf-cutting ant Atta laevigata (Formicidae: Attini) marks its territory with colony-specific Dufour gland secretion. In: Journal of Chemical Ecology. Volume 18, Issue 2, 1992, pp. 183-196.
- ^ Mary EA Whitehouse, Klaus Jaffe: Ant wars: combat strategies, territory and nest defense in the leaf-cutting ant Atta laevigata. In: Animal Behavior. 51, 1996, pp. 1207-1217.
- ^ Alan N Costa, Heraldo L. Vasconcelos, Ernane HM Vieira-Neto, Emilio M. Bruna: Do herbivores exert top-down effects in Neotropical savannas? Estimates of biomass consumption by leaf-cutter ants. In: Journal of Vegetation Science. 19, 2008, pp. 849-854. doi: 10.3170 / 2008-8-18461
- ↑ HG Fowler, VP Silva, NB Saes: Population dynamics of leaf-cutting ants: a brief review. In: CS Lofgren, RK Van der Meer (Ed.): Fire Ants and Leaf-Cutting Ants: Biology and Management. West-View Press, Boulder, Colorado 1986, pp. 123-145.
- ↑ ACO Silva-Pinhati, M. Bacci Jr., G. Hinkle, ML Sogin, FC Pagnocca, VG Martins, OC Bueno, MJA Hebling: Low variation in ribosomal DNA and internal transcribed spacers of the symbiotic fungi of leaf-cutting ants ( Attini: Formicidae). In: Brazilian Journal of Medical and Biological Research. vol. 37, no.10, 2004. (online)
- ↑ AS Mikheleyev, UG Mueller, JJ Boomsma: Population genetic signatures of diffuse co-evolution between leaf-cutting ants and their cultivar fungi. In: Molecular Ecology. 16, 2007, pp. 209-216. doi: 10.1111 / j.1365-294X.2006.03134.x
- ↑ Frederick Smith : Hymnenopterous Insects in the Collection of the British Museum. Part VI. Formicidae . London 1858.
- ↑ Maurício Bacci Jr., Scott E. Solomon, Ulrich G. Mueller, Vanderlei G. Martins, Alfredo OR Carvalho, Luiz GE Vieira, Ana Carla O. Silva-Pinhati: Phylogeny of leafcutter ants in the genus Atta Fabricius (Formicidae: Attini ) based on mitochondrial and nuclear DNA sequences. In: Molecular Phylogenetics and Evolution. 51, 2009, pp. 427-437. doi: 10.1016 / j.ympev.2008.11.005
- ↑ Thomas Borgmeier: Atta studies. In: Memorias de Instituto Oswaldo Cruz. 48, 1950, pp. 265-292.
- ↑ Jacques HC Delabie: Atta silvai Goncalves, sininimo junior de Atta laevigata (Fred Smith.). In: Revista Brasileira de Entomologia. 41 (2-4), 1998, pp. 339-341. (on-line)
- ↑ Joshua Goodman: Crunchy, Big-Butt Ants Entice Gourmands ( Memento of the original from February 18, 2012 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. . Discovery Channel , Aug. 14, 2006; Retrieved April 2, 2010.
