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Subfamily FORMICINAE
Tribe CAMPONOTINI

Camponotus (Myrmothrix) planatus Roger, 1863
"compact carpenter ant"

Authors: Joe A. MacGown and Ryan J. Whitehouse
Uploaded, 2009; last updated 17 August 2016

Camponotus planatus, full face view of a worker (MS, Hancock Co.) (photo by Joe A. MacGown)
Camponotus planatus, lateral view of a worker (MS, Hancock Co.) (photo by Joe A. MacGown)
Camponotus planatus, dorsal view of a worker (MS, Hancock Co.) (photo by Joe A. MacGown)
Camponotus planatus, full face view of a worker (MS, Hancock Co.) (photo by Joe A. MacGown)
Camponotus planatus, lateral view of a worker (MS, Hancock Co.) (photo by Joe A. MacGown)

Introduction
Ants in the genus Camponotus are collectively known as carpenter ants because some species nest in wood, including man-made structure. This genus includes some of the largest and most common ants in the world, and they are found in all biogeographical regions (Bolton, 1995).  More than 900 species of Camponotus are known worldwide, with 50 species reported from the United States (Hanson and Klotz, 2005), and 20 species found east of the Mississippi River (Deyrup, 2003; Smith, 1979). 

Species in this genus are variable in size with workers ranging in size from 3.0 to 15 mm or more in length and queens (also referred to as females) of some species attaining a length of 19 mm or more. Many species are polymorphic. Workers have a 12-segmented antenna that lacks an apical club. Antennal fossae do not touch the posterior border of the clypeus. Ocelli are not present on the heads of workers. The workers of most species have an indistinct metanotal suture between the promesonotum and the propodeum, although this suture is present in C. sexguttatus and some members of the subgenus Colobopsis.  Those species that lack the obvious and deep metanotal suture have the shape of the alitrunk in a smoothly curved arc (as seen in profile). 

Camponotus planatus, commonly called the compact carpenter ant, is an exotic species found in southern Florida. This tropical species occurs in Cuba and from Mexico to Colombia, southern Texas, New Mexico, southern Florida, especially the Keys and Hancock County, Mississippi.

Taxonomic History (Bolton 2016)
Camponotus (Myrmobrachys) planatus Roger, 1863: 148 (s.w.q.m.) CUBA. Neotropic. 
Wheeler & Wheeler, 1953: 194 (l.). Combination in Camponotus (Myrmobrachys): Forel, 1914a: 271. Subspecies of Camponotus senex: Forel, 1879: 97; Emery, 1890: 56. Revived status as species: Dalla Torre, 1893}: 248; Forel, 1899: 141; Forel, 1901: 371. Current subspecies: nominal plus Camponotus planatus acaciae, Camponotus planatus colombicus, Camponotus planatus continentis, Camponotus planatus esdras.

Identification
Major Worker: HL 1.76-1.84mm, HW 1.84-1.94mm, SL 1.38-1.44mm, EL 0.47-0.50mm, MeSL 1.76-1.87mm (n=5) (MEM specimens). Total length 5.0-6.0mm. Head, mesosoma, waist, and prolegs a reddish brown, with the gaster and hind two pairs of legs blackish. Head, mesosoma, waist, and gaster all with long, erect, whitish setae. Head not shinning and slightly wider than long, almost square; eyes well developed and located near the occipital border; mandibles with five teeth; maxillary palps long and 6-segmented; antennal scapes just surpassing the occipital border; antennae 12-segmented. Mesosoma not shining with the dorsal surface evenly curved; humeral shoulders well defined. Waist is 1-segmented; node flat in the lateral view and wider at the apex in the posterior view. Gaster with a mixture of dense, appressed setae and erect setae; acidopore present.

Minor Worker: HL 1.12-1.28mm, HW 1.05-1.22mm, SL 1.20-1.28mm, EL 0.35-0.38mm, MeSL 1.40-1.48mm (n=5) (MEM specimens). Small, carpenter ant with an overall total length of 3.5-4.0mm. Head, mesosoma, waist, and prolegs reddish brown with a blackish gaster. The hind two pairs of legs darker than the mesosoma, but lighter than the gaster. Head, mesosoma, waist, and gaster all with long, erect, whitish setae. Head not shining and not as boxy as the major worker; eyes well developed and located near the occipital border; mandibles with five teeth; maxillary palps long and 6-segmented; antennal scapes exceeding the occipital border; antennae 12-segmented. Mesosoma not shinning with the dorsal surface evenly curved; humeral shoulders well defined. Waist is 1-segmented; petiolar node same as the major worker. Gaster with slightly less appressed setae than the major worker; acidopore present.

Queen: HL 1.34mm, HW 1.19mm, SL 1.23mm, EL 0.46mm, MeSL 2.04mm (n=1) (MEM specimen). Head, mesosoma, and waist reddish brown while the legs and gaster are blackish. Erect, whitish setae present of most surfaces. Head not shinning and slightly longer than wide, not as square as the major worker; eyes well developed and located near the occipital border; three ocelli present; mandibles with five teeth; maxillary palps long and 6-segmented; antennal scape exceeding occipital border; antennae 12-segmented. Mesosoma not shining with short, erect setae on the dorsal surface; four wings or wing scars present. Waist 1-segmented; node flat in the lateral view and widest at the apex, vaguely heart shaped. Gaster with a mixture of dense appressed setae and erect setae; acidopore present.

Male: (no specimens in MEM).

Biology and Economic Importance
Camponotus planatus is a widely distributed tropical species found throughout Central America, Mexico, Cuba, and in the USA in the southern tip of Florida in the Keys, in southern Texas and New Mexico, and southern Mississippi. Deyrup (2001) stated that this species has always been considered to be native in Florida, though he appears to question that by asking questions about why it is mostly confined to the Florida Keys even though there is suitable habitat on the mainland. This species does occur in mainland Florida, but is not widespread. Populations in the Southwest are almost certainly native and simply extensions of their natural range from Mexico. However, populations in Hancock County, Mississippi are most likely introduced to that state from Florida. The first collections of C. planatus from Mississippi were made at an outdoor nursery that imported live palms from southern Florida. Subsequent collections of this species were made at a different locality in the same county several years later, and after the palm nursery was no longer in business.

Colonies are reported to be small and typically arboreal and nests may be in places such as hollow twigs, old termite galleries in dead wood, grass clumps, voids in tree trunks, and leaf axil bases in palms (Deyrup et al. 2000). According to Deyrup et al. (2000), C. planatus is most common in Florida in the Keys where it is a dominant ant in tropical hammocks. Populations are also known to occur in mainland sites in Florida. MacGown has collected this species in coastal Mississippi in Hancock County where it appears to be established. This species may be a significant predator of native ants and other arthropods, and it has been reported to protect honeydew producing insects (Deyrup et al. 2000).

At the moment, C. planatus is not considered to be a big economic threat.

Distribution
Native Range: Central America and Northern South America (AntWiki.org).

Neotropical Region: Colombia, Costa Rica, Cuba, Ecuador, El Salvador, Guadeloupe, Guatemala, Honduras, Mexico, Nicaragua, Panama, Venezuela (AntWeb.org).
Nearctic Region: United States (AntWeb.org and MEM).

U.S. Distribution: FL, MS, NM, TX (Deyrup 2001 and MEM).
Southeastern U.S. Distribution: FL, MS (Deyrup 2001 and MEM).

Acknowledgments
Funding for the ant work being done by the MEM in Alabama and Mississippi is from several sources including the National Institute of Food and Agriculture, United States Department of Agriculture, under Project No. MIS-012040, the Mississippi Agricultural and Forestry Experiment Station at Mississippi State University, with support from State Project MIS-311080, NSF Grants BSR-9024810 and DFB-9200856, the Tombigbee National Forest (U.S. Forest Service), the Noxubee Wildlife Refuge, Mississippi Natural Heritage Program Research Grant, USDA Forest Service Agreement No. 08-99-07-CCS-010, the William H. Cross Expedition Fund, and primarily by the USDA-ARS Areawide Management of Imported Fire Ant Project. Additionally, special cooperation has been provided by State Parks, National Forests, National Wildlife Refuges, the Natchez Trace Parkway, and from various private landowners in both Alabama and Mississippi.

Literature Cited

Bolton, B. 2016.  Bolton World Catalog Ants. Available online: http://www.antweb.org/world.jsp. Accessed 9 March 2016.

Dalla Torre, K. W. 1893. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. Vol. 7. Formicidae (Heterogyna). Leipzig: W. Engelmann, 289 pp.

Deyrup, M. 1991. Exotic ants of the Florida Keys. (Hymenoptera: Formicidae). Proc. 4th Sym. Nat. Hist. Bahamas: 15-22.

Deyrup, M.  2003. An updated list of Florida ants (Hymenoptera: Formicidae). Florida Entomologist 86: 43-48.

Deyrup, M., Davis, L. & Cover, S. 2000. Exotic ants in Florida. Transactions of the American Entomological Society 126, 293-325.

Emery, C. 1890. Studii sulle formiche della fauna neotropica. Bullettino della Società Entomologica Italiana 22:38-80.

Forel, A. 1879. Études myrmécologiques en 1879 (deuxième partie [1re partie en 1878]). Bulletin de la Société Vaudoise des Sciences Naturelles 16:53-128. 

Forel, A. 1899. Formicidae. Dummy reference. Biologia Centrali-Americana Hym 3:1-169. 

Forel, A. 1901. Variétés myrmécologiques. Annales de la Société Entomologique de Belgique 45:334-382.

Forel, A. 1914. Le genre Camponotus Mayr et les genres voisins. Revue Suisse de Zoologie 22:257-276. 

Hansen, L. D., and J. H. Klotz. 2005.  Carpenter ants of the United States and Canada.  Cornell University Press.  Ithaca, N. Y.  i-xii+204 pp.

Roger, J. 1863. Die neu aufgeführten Gattungen und Arten meines Formiciden-Verzeichnisses nebst Ergänzung einiger früher gegebenen Beschreibungen. Berliner Entomologische Zeitschrift 7:131-214. 

Smith, D. R. 1979.  In Catalog of Hymenoptera in America north of Mexico. Smithsonian Institution Press, Washington D. C.  Vol. 2, pp. 1323-1427. 

Wheeler, G. C. and J. Wheeler. 1953. The ant larvae of the subfamily Formicinae. Part II. Annals of the Entomological Society of America 46:175-217.

LINKS

AntCat
AntWeb
AntWiki
Discover Life Images

Fact sheet: http://entnemdept.ufl.edu/creatures/urban/ants/c_planatus.htm
Info, identification, etc. http://www.evergreen.edu/Ants/genera/camponotus/species/planatus/planatus.html