Subfamily FORMICINAE
Tribe CAMPONOTINI
Camponotus (Myrmothrix) planatus Roger, 1863
"compact carpenter ant"

Authors: Joe A. MacGown and Ryan J. Whitehouse
Uploaded, 2009; last updated 26 August 2016

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 Roger (Formicinae), the compact carpenter ant, is a small, bicolored species thought to be native to Central America and northern South America. This tropical species occurs in Cuba and from Mexico to Colombia, southern Texas, 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, 1914: 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.

Diagnosis
Camponotus planatus is easily distinguished from other species in the Southeast by its small size as compared to other carpenter ants (TL ≈ 3.5–6.0 mm, bicoloration (reddish brown except for dark blackish brown gaster), strongly arched mesosoma, lack of spines, single petiolar node, and abundant, elongate, white setae that cover much of the body except for the scapes. The strong pilosity and small size will separate C. planatus from most other bicolored carpenter ants in our region except for C. floridanus, which is larger, has black scapes, and has erect setae present on the scapes.

Identification
Major Worker: Small: TL ≈ 5.0-6.0mm, 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). Head, mesosoma, waist, and forelegs reddish brown, gaster and mid and hindlegs blackish. Head slightly wider than long, sqarish; integument finely punctate, not shiny, with abundant, short and long, white setae present except on scapes, which lack erect setae; eyes located near the above midline of head; mandibles with five teeth;maxillary palps long and 6-segmented; scapes barely surpass the occipital border; antennae 12-segmented. Mesosomal dorsum strongly and evenly curved; integument finely punctate, not shiny; entire mesosomal dorsum with abundant, long, erect, whitish setae; pronotal humeral area well defined. Waist with single, erect petiolar node, widening apically (as seen from front to back); shiny, with numerous, long, white setae. Gaster with fine microsculpture, not shining, with dense, appressed, pubescence and abundant, long, semi erect, whitish setae acidopore present.

Minor Worker: Smaller than major worker: TL ≈3.5-4.0mm, 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). Head, mesosoma, waist, and forelegs reddish brown, gaster and mid and hindlegs blackish. Head slightly wider than long, widest posteriorly and gradually narrowing anteriorly; integument finely punctate, not shiny, with abundant, short and long, white setae present except on scapes, which lack erect setae; eyes located near the above midline of head; mandibles with five teeth; maxillary palps long and 6-segmented; scapes surpassing posterior border of head by about ½ their length; antennae 12-segmented. Mesosomal dorsum strongly and evenly curved; integument finely punctate, not shiny; entire mesosomal dorsum with abundant, long, erect, whitish setae; pronotal humeral area well defined. Waist with single, erect petiolar node, widening apically (as seen from front to back); shiny, with numerous, long, white setae. Gaster with fine microsculpture, not shining, with dense, appressed, pubescence and abundant, long, semi erect, whitish setae; acidopore present.

Queen: About the size of major worker: TL ≈ 5.0-6.0mm, HL 1.34mm, HW 1.19mm, SL 1.23mm, EL 0.46mm, MeSL 2.04mm (n= 5) (MEM specimens). Head slightly longer than wide, widest posteriorly; integument finely punctate, not shiny, with abundant, short and long, white setae present except on scapes, which lack erect setae; eyes large, located near posterior edge of head and extending past edges of head in full face view; three ocelli present; mandibles with five teeth; maxillary palps long and 6-segmented; scapes barely surpass the occipital border; antennae 12-segmented. Mesosomal dorsum enlarged, rounded flattened dorsally, with wing scars or wings present; integument finely punctate, not shiny; entire mesosomal dorsum with abundant, long, erect, whitish setae; pronotal humeral area well defined. Forewing with two submarginal cells; hindwing with more simple venation, basal cell present. Waist with single, erect petiolar node, widening apically (as seen from front to back); shiny, with numerous, long, white setae. Gaster with fine microsculpture, not shining, with dense, appressed, pubescence and abundant, long, semi erect, whitish 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 southern Mississippi. Deyrup (2003) 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 (MacGown 2010). Based on collections and observeations at additional localities in the same county since its initial detection, and after the palm nursery was no longer in business, this species appears to be established in the region.

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 competitor of native ants and other arthropods, and it has been reported to protect honeydew producing insects (Deyrup et al. 2000).

Pest Status
Currently, C. planatus is not considered to be a serious economic threat, at least in Mississippi, although it has potential to be a pest as it sometimes nests in wood.

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, TX (Deyrup 2003 and MEM).

Southeastern U.S. Distribution: FL, MS (Hancock Co.) (Deyrup 2003 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 (2001-2014) and USDA-ARS Areawide Management Invasive Ants 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.

MacGown, J. A. 2010.  Camponotus planatus (Hymenoptera: Formicidae), an exotic carpenter ant found in Mississippi.  Journal of the Mississippi Academy of Sciences 55: 187-18

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

AntWeb
AntCat
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