Crematogaster distans

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Crematogaster distans
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Crematogaster
Species: C. distans
Binomial name
Crematogaster distans
Mayr, 1870

Crematogaster distans casent0103431 profile 1.jpg

Crematogaster distans casent0103431 dorsal 1.jpg

Specimen labels

Synonyms

Forming large colonies, but not in high density, in seasonally dry, open or brushy habitats.

Identification

Keys including this Species

Distribution

Longino (2003) - The species complex occurs from southern USA (Texas) to Argentina.

Distribution based on Regional Taxon Lists

Nearctic Region: United States.
Neotropical Region: Argentina, Brazil, Colombia (type locality), Costa Rica, Ecuador, Mexico, Nicaragua, Panama, Peru, Venezuela.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Longino (2003) - I have only three records of C. distans from Costa Rica, two older museum collections from the Central Valley, and one collection from La Selva Biological Station in the Atlantic lowlands. It is clear from material elsewhere in the range of the species that distans prefers seasonally dry, open or brushy habitats.

In general, distans has very large colonies that are low density. The one La Selva collection I observed was from a recent treefall. A large dead trunk had fallen, bringing a large Bauhinia vine tangle down with it. Crematogaster distans dominated the treefall, with columns of abundant workers spread throughout and streaming back to the canopy along lianas. I did not find any nest center or brood, but I did find two alate queens along with a worker aggregation in a hollow stick. In the Santa Marta region of Colombia I observed a distans nest in a dead stick, and on another occasion I found workers tending Coccoidea on Cnidoscolus (Euphorbiaceae). In a second growth forest in Venezuela I observed columns of workers descending a tree trunk and spreading out onto an Inga sapling, where large numbers of workers were tending scale insects.

Nothing is known of colony founding, but queens exhibit a morphology often associated with social parasitism. Kusnezov (1949) described the now synonymized Crematogaster descolei from a single alate queen and suggested that it was a workerless social parasite because of the small size and shiny integument. Kempf (1968) refuted this by reporting worker-associated colonies. The discovery of a colony of distans at La Selva with queens identical to descolei confirms the synonymy of descolei under distans. It is possible that Crematogaster distans is a temporary social parasite, requiring colonies of host species to establish new colonies of its own, but it is not workerless.

It is possible there are multiple sympatric forms in the Neotropics, with queens being much more differentiable than workers. Observations suggest the possibility there are at least three forms: (1) descolei-like, the queens of which are hairless and long petiolate, (2) a widespread form with hairless queens and short petioles, and (3) a setose form, with abundant setae on queens and workers. But much more queen-associated material and some thorough morphometrics will be needed to confirm or modify these patterns. I have followed the “synonym until proven distinct” approach by formally synonymizing descolei under distans.

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • distans. Crematogaster distans Mayr, 1870a: 402 (w.) COLOMBIA. Kempf, 1968b: 392 (q.). Combination in C. (Orthocrema): Emery, 1922e: 134; in C. (Neocrema): Santschi, 1918d: 182; Kempf, 1972a: 83. Senior synonym of cordinoda, paraensis, parviceps, pevsnerae, vanda: Kempf, 1968b: 390; of descolei: Longino, 2003a: 59.
  • paraensis. Crematogaster distans r. paraensis Forel, 1904c: 37 (w.) BRAZIL. Junior synonym of distans: Kempf, 1968b: 390.
  • parviceps. Crematogaster distans subsp. parviceps Forel, 1908c: 369 (w.) BRAZIL. Combination in C. (Orthocrema): Emery, 1922e: 135. Junior synonym of distans: Kempf, 1968b: 390.
  • pevsnerae. Crematogaster distans r. pevsnerae Forel, 1912f: 218 (w.) VENEZUELA. Combination in C. (Orthocrema): Emery, 1922e: 135. Junior synonym of distans: Kempf, 1968b: 390.
  • cordinoda. Crematogaster distans var. cordinoda Forel, 1914e: 12 (w.) COLOMBIA. Combination in C. (Orthocrema): Emery, 1922e: 135. Junior synonym of distans: Kempf, 1968b: 390.
  • vanda. Crematogaster distans subsp. vanda Borgmeier, 1929: 209 (w.) BRAZIL. Junior synonym of distans: Kempf, 1968b: 390.
  • descolei. Crematogaster (Neocrema) descolei Kusnezov, 1949e: 587, figs. 1-4 (q.) ARGENTINA. Junior synonym of distans: Longino, 2003a: 59.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Longino (2003) - HL 0.699, 0.627, 0.698; HW 0.712, 0.649, 0.696; HC 0.671, 0.610, 0.653; SL 0.563, 0.479, 0.564; EL 0.143, 0.157, 0.167; A11L 0.284; A11W 0.135; A10L 0.135; A10W 0.107; A09L 0.069; A09W 0.086; A08L 0.046; A08W 0.069; WL 0.784, 0.686, 0.773; SPL 0.147, 0.140, 0.127; PTH 0.212, 0.187, 0.195; PTL 0.299, 0.258, 0.288; PTW 0.297, 0.295, 0.289; PPL 0.194, 0.180, 0.203; PPW 0.321, 0.286, 0.320; CI 102, 104, 100; OI 20, 25, 24; SI 81, 76, 81; PTHI 71, 72, 68; PTWI 99, 114, 100; PPI 165, 159, 158; SPI 19, 20, 16; ACI 0.56.

Color dark red brown to black.

Mandible largely smooth and shiny, with very faint striae; clypeus emarginate anteriorly, convex, smooth and shiny; face smooth and shiny; scape with moderately abundant, short, fully appressed pilosity and no erect setae; terminal 2-3 segments of antenna sequentially longer and more densely pubescent, especially terminal two, forming 2-segmented club; face and ventral surface of head with sparse short appressed pubescence and no erect setae; no erect setae projecting from sides of head in full face view.

In lateral view, promesonotum compressed, pronotum short but strongly convex, mesonotum projecting above pronotum and propodeum, dropping steeply to propodeal suture; propodeum with short, weakly differentiated dorsal face; propodeal suture deep, Vshaped, but suture partially obscured in lateral view by small lateral carinulae that bridge suture; propodeal spines short, conical, upturned; side and most of dorsum of mesosoma with faint punctation or weak microareolate sculpture, becoming smooth and shiny on posterior face of propodeum; mesonotum with a pair of short, stiff, erect setae, otherwise erect setae lacking on mesosoma; legs with sparse, fully appressed pubescence.

Petiole in side view subtrapezoideal, with faint microareolate surface sculpture; anteroventral tooth a shallow, obtuse gibbosity, not produced or angulate; dorsal face subrectangular, slightly longer than wide, smooth and shiny, anterolateral portions somewhat produced as lobes, anteromedian region depressed, sides approximately parallel anteriorly, converging posteriorly; postpetiole with small acute ventral tooth, postpetiole in dorsal view bilobed, wider than long, with longitudinal median sulcus, posterior margin emarginate; fourth abdominal tergite with faint microareolate sculpture; pair of stiff setae on posterodorsal petiole, two pairs on postpetiole, and about 20 stiff setae on fourth abdominal tergite.

Queen

Longino (2003) - In lateral profile dorsal face of propodeum sloping obliquely from postscutellum, such that most of propodeum is posterior to scutellum (in contrast to normal queens, in which dorsal face of propodeum drops steeply from postscutellum and much of propodeum appears ventral to scutellum and postscutellum); entire body, including scape, mandible, face, mesosoma, petiole, postpetiole, and fourth abdominal tergite extremely smooth and shiny, glass-like; propodeal spines completely absent; petiole and postpetiole robust, generally similar to worker in shape but completely lacking anteroventral petiolar tooth of any kind; remarkably devoid of erect setae or pubescence, funiculus and terminal segments of tarsi with typical subdecumbent pubescence, but no trace of pubescence or erect setae anywhere else on body; size characters as in Figures.

Type Material

Longino (2003) - Lectotype worker: Colombia (Lindig) Naturhistorisches Museum Wien, Vienna (examined).

References