''Eciton'' is a

New World The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas, and sometimes Oceania."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: ...

army ant The name army ant (or legionary ant or ''marabunta'') is applied to over 200 ant species in different lineages. Because of their aggressive predatory foraging groups, known as "raids", a huge number of ants forage simultaneously over a limited ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

that contains the most familiar

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of army ants. The most predominant and well-known species is ''

Eciton burchellii ''Eciton burchellii'' is a species of New World army ant in the genus '' Eciton''. This species performs expansive, organized swarm raids that give it the informal name, ''Eciton'' army ant. This species displays a high degree of worker polymor ...

'', which is also more commonly known as the army ant and is considered the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

. ''

'' 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 southern

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

to the northern part of

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

Life cycle

''Eciton'' army ants have a bi-phasic lifestyle in which they alternate between a nomadic phase and a

statary Statary is a term currently applied in fields such as ecology, ethology, psychology. In modern use it contrasts on the one hand with such concepts as ''migratory'', ''nomadic'', or ''shifting'', and on the other with ''static'' or ''immobile''. Th ...

phase. In the statary phase, which lasts about three weeks, the ants remain in the same location every night. They arrange their own living bodies into a nest, protecting the queen and her eggs in the middle. Such a temporary home is called a " bivouac". In the nomadic phase the ants move their entire

colony A colony is a territory subject to a form of foreign rule, which rules the territory and its indigenous peoples separated from the foreign rulers, the colonizer, and their ''metropole'' (or "mother country"). This separated rule was often orga ...

to a new location nearly every night for about two weeks on end. During said phase, the queen does not lay eggs. When the ants enter the statary phase, the queen's body swells massively and she lays as many as 80,000 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 A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e causes the colony to enter the nomadic phase. The colony swarms much more intensely and does so nearly every day, and the ants move to a new location nearly every night. After two weeks, around the time when the larvae begin to

pupa A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...

te, the colony again enters the statary phase, and the cycle begins anew. 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 (mostly

crickets Crickets are orthopteran insects which are related to bush crickets and more distantly, to grasshoppers. In older literature, such as Imms,Imms AD, rev. Richards OW & Davies RG (1970) ''A General Textbook of Entomology'' 9th Ed. Methuen 886 ...

and roaches) 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 are

inquiline In zoology, an inquiline (from Latin ''inquilinus'', "lodger" or "tenant") is an animal that lives commensally in the nest, burrow, or dwelling place of an animal of another species. For example, some organisms, such as insects, may live in the ...

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 — mostly

cuckoo Cuckoos are birds in the Cuculidae ( ) family, the sole taxon in the order Cuculiformes ( ). The cuckoo family includes the common or European cuckoo, roadrunners, koels, malkohas, couas, coucals, and anis. The coucals and anis are somet ...

s, woodcreepers,

tanager The tanagers (singular ) comprise the bird family (biology), family Thraupidae, in the order Passeriformes. The family has a Neotropical distribution and is the second-largest family of birds. It represents about 4% of all avian species and 12 ...

s, and

antbird The antbirds are a large passerine bird family, Thamnophilidae, found across subtropical and tropical Central and South America, from Mexico to Argentina. There are more than 230 species, known variously as antshrikes, antwrens, antvireos, fire ...

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 family

Hesperiidae Skippers are a group of butterflies placed in the family Hesperiidae within the order Lepidoptera (moths and butterflies). They were previously placed in a separate superfamily, Hesperioidea, but have since been placed in the superfamily Papilion ...

) that feed almost exclusively on the

feces Feces (also known as faeces American and British English spelling differences#ae and oe, or fæces; : faex) are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the ...

of these bird species.

Parasites

The

mite Mites are small arachnids (eight-legged arthropods) of two large orders, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari. However, most recent genetic analyses do not recover the two as eac ...

'' Trichocylliba crinita'' (Elzinga & Rettenmeyer, 1975) (

Mesostigmata Mesostigmata is an order of mites belonging to the Parasitiformes. They are by far the largest group of Parasitiformes, with over 8,000 species in 130 families. Mesostigmata includes parasitic as well as free-living and predatory forms. They ca ...

Uropodidae Uropodidae is a family of mites in the order Mesostigmata. Description As part of superfamily Uropodoidea, Uropodidae are tortoise-like mites with an oval to circular outline, and with armour both dorsally and ventrally. They can be distinguis ...

) was found on the jaws of the species '' Eciton dulcium'', and nowhere else.Picture
(hairy brown spheres are the mites)

Species

*''

'' (Westwood, 1842) *'' Eciton drepanophorum'' Smith, 1858 *'' Eciton dulcium'' Forel, 1912 *'' Eciton hamatum'' (Fabricius, 1782) *'' Eciton jansoni'' Forel, 1912 *'' Eciton lucanoides'' Emery, 1894 *'' Eciton mexicanum'' Roger, 1863 *'' Eciton quadriglume'' (Haliday, 1836) *'' Eciton rapax'' Smith, 1855 *'' Eciton setigaster'' Borgmeier, 1953 *'' Eciton uncinatum'' Borgmeier, 1953 *'' Eciton vagans'' (Olivier, 1792)

References

External links

Tree of Life - Eciton

Discover Life - Formicidae: Eciton

''Eciton'' of Costa Rica
{{Authority control Dorylinae Ant genera Hymenoptera of South America Hymenoptera of North America