Eciton hamatum

von Beeren et al. (2018) found the Wasmannian mimic rove-beetle Ecitophya gracillima in colonies of this species in La Selva biological station in Costa Rica. An analysis of cuticular hydrocarbons showed both the ants and beetle had similar CHC profiles. Laboratory behavioral assays showed the beetles sought contact with host ants and often engaged in reciprocal grooming behavior with workers.

Identification
Jack Longino:

Minor worker: head, mesosoma, and metasoma evenly orange yellow; occipital tooth present; petiolar teeth in the form of short, acute flanges, separate or joined into a scoop-like structure, and with short separate carinae extending to a variable extent onto the posterior face, never fused into a single median carina on the posterior face; petiole long and low, subrectangular, with no anterodorsal elevated flange; fourth abdominal tergite with short, sparse appressed pubescence beneath erect setae.

Major worker: face smooth and shiny, not matte; long sickle-shaped mandibles simple, without tooth on inner margin; other characters as in minor.

Similar species: Eciton lucanoides.

Distribution based on Regional Taxon Lists
Neotropical Region: Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, Suriname, Trinidad and Tobago, Venezuela.

Biology
Jack Longino: In lowland wet forest habitats this is one of the most common Eciton species. Raids are always in columns, never in a carpet like Eciton burchellii. Raids can be day or night, and I frequently observe raiding columns ascending trees. Prey are often brood of vespid wasps and the ant genera Dolichoderus and Camponotus, suggesting that E. hamatum is mainly an arboreal forager.

Castes

 * Worker

Nomenclature

 *  hamatum. Formica hamata Fabricius, 1782: 494 (s.) FRENCH GUIANA. Mayr, 1886b: 121 (w.); Emery, 1896g: 39 (m.); Wheeler, W.M. 1925c: 145 (q.); Wheeler, G.C. 1943: 327 (l.). Combination in Eciton: Latreille, 1804: 179; in Camptognatha: Gray, G.R. 1832: 16; in Eciton: Smith, F. 1855c: 161. Senior synonym of curvidentata: Smith, F. 1858b: 148; of amazona, funesta, mattogrossensis, pittieri: Borgmeier, 1953: 14, 13, 10, 9 repectively; of testacea: Kempf, 1972a: 102. See also: Borgmeier, 1955: 214; Tafuri, 1957: 21; Wheeler, G.C. & Wheeler, J. 1964c: 134; Wheeler, G.C. & Wheeler, J. 1984: 269.
 * curvidentata. Formica curvidentata Latreille, 1802c: 269, pl. 8, fig. 55 (w.) FRENCH GUIANA. Combination in Eciton: Lepeletier, 1835: 179. Junior synonym of hamatum: Smith, F. 1858b: 148.
 * testacea. Camptognatha testacea Gray, G.R. 1832: 516, pl 76, fig. 4 (w.) no locality given. Junior synonym of hamatum: Kempf, 1972a: 102.
 * pittieri. Eciton pittieri Forel, 1899c: 24, pl. 1, fig. 15 (w.) COSTA RICA. Combination in E. (Labidus): Emery, 1910b: 23; in E. (Holopone): Santschi, 1925b: 11. Junior synonym of hamatum: Borgmeier, 1953: 9.
 * mattogrossensis. Eciton hamatum var. mattogrossensis Luederwaldt, 1920: 4 (w.) BRAZIL. Santschi, 1925d: 221 (s.m.); Reichensperger, 1926: 401 (q.). Raised to species: Santschi, 1925d: 221. Junior synonym of hamatum: Borgmeier, 1953: 10.
 * funesta. Eciton hamatum var. funesta Santschi, 1921g: 89 (s.w.) COSTA RICA. Junior synonym of hamatum: Borgmeier, 1953: 13.
 * amazona. Eciton amazona Santschi, 1923d: 68 (s.w.) BRAZIL. Subspecies of mattogrosense: Santschi, 1925d: 221. Junior synonym of hamatum: Borgmeier, 1953: 14.

References based on Global Ant Biodiversity Informatics

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