- Eciton
regnum =Animal ia
phylum =Arthropod a
subphylum =Hexapoda
classis =Insect a
ordo =Hymenoptera
subordo =Apocrita
superfamilia =Vespoidea
familia =Formicidae
subfamilia =Ecitoninae
tribus =Ecitonini
genus = "Eciton"
genus_authority =Latreille , 1804
subdivision_ranks = Species
subdivision = "Eciton burchellii " "Eciton drepanophorum " "Eciton dulcium " "Eciton hamatum " "Eciton jansoni " "Eciton lucanoides " "Eciton mexicanum " "Eciton quadrigiume " "Eciton rapax " "Eciton setigaster " "Eciton uncinatum " "Eciton vagans "The
New World army ant genus "Eciton" contains the most familiarspecies of army ants. The most predominant and well-known species is "Eciton burchellii ", whose common name is "army ant" and which is considered to be the archetypal species."
Eciton burchellii " and "Eciton hamatum " are the most visible and best studied of the New World army ants because they forage above ground and during the day, in enormous raiding swarms. Their range stretches from southernMexico to the northern part ofSouth America .Life-cycle
"Eciton" army ants have a bi-phasic lifestyle in which they alternate between a nomadic phase and a stationary stage. In the stationary or statary phase ("statary" means "standing in place"), which lasts about three weeks, the ants remain in the same location every night. They make a nest out of their own bodies, protecting the queen and her eggs in the middle. This temporary home is known as a "bivouac". In the nomadic phase the ants move their entire colony to a new location nearly every night for two weeks.
When the ants enter the statary phase, the queen's body swells massively and she lays as many as 250,000 eggs in less than a week. While the eggs mature, the ants swarm with less frequency and intensity. When the eggs hatch, the excitement caused by the increased activity of the
larva e causes the colony to enter the nomadic phase. The colony swarms much more intensely and nearly every day, and the ants move to a new location every night. After two weeks, around the time when the larvae begin topupa te, the colony again enters the statary phase, and the cycle begins anew (Schneirla, 1971).Because of the regularity and intensity of "E. burchelli" and "E. hamatum" swarms, many insect and bird species have evolved complex relationships with these ants. There are conopid flies (the entire genus "
Stylogaster ") that are obligate associates of army ant raids, and females lay their eggs on insects (mostlycricket s androach es) flushed into the open by the ants, and there are also some tachinid flies that are somewhat similar in behavior. There are ant-mimicking staphylinid beetles, shaped like the ants they follow, that run with the swarm, some of them preying on stragglers or other insects injured or flushed by army-ant activity, though most of these areinquiline s in the ant nest; these and other insects sometimes spend their entire lives hidden in "Eciton" colonies, often mimicking the ants or their larvae. Many species of birds—mostlycuckoo s,woodcreeper s,tanager s, andantbird s—feed near the swarms. About 50 of the approximately 200 species of antbirds specialize in preying on insects fleeing the ants, getting up to half their food this way. Some of these birds actively check army-ant bivouacs each morning and follow the foraging trail to the swarm front, where they take positions based on their species' relations in a dominance hierarchy. A swarm may be attended by as many as 25 birds of one or two "professional" species and individual birds of as many as 30 other species. There are even butterflies (esp. the tribeIthomiini ) that feed almost exclusively on thefeces of these bird species.Parasites
The
mite "Trichocylliba crinita" (Elzinga & Rettenmeyer, 1975) (Mesostigmata :Uropodidae ) was found on the jaws of the species "Eciton dulcium ", and nowhere else. [ [http://www.lib.uconn.edu/about/exhibits/naturex3/ant.htm Picture] (hairy brown spheres are the mites)]Footnotes
References
(Some of the text above is used with permission of the author Tim Brown, from his [http://www.infiniteworld.org/research/introduction.htm InfiniteWorld] website)
*cite book | author = Schneirla, T.C. | year = 1971 | title = Army ants. A study in social organization | editor = H. R. Topoff (Ed.) | publisher = W. H. Freeman & Co | location = San Francisco | id = ISBN 0-7167-0933-3
* (1990): "The Ants" ISBN 3540520929 (Pulitzer Prize)External links
* [http://tolweb.org/Eciton/22637 Tree of Life - Eciton]
* [http://tolweb.org/tree?group=Ecitoninae&contgroup=Dorylomorphs Tree of Life - Ecitoninae]
* [http://stri.discoverlife.org/mp/20q?search=eciton Discover Life - Formicidae: Eciton]
* [http://www.evergreen.edu/Ants/Genera/eciton/ "Eciton" of Costa Rica]
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