Carpenter Ants (Formicidae: Camponotus) of Mississippi Joe A. MacGown, Richard L. Brown, and JoVonn G. Hill Mississippi Entomological Museum Mississippi State University Box 9775, Mississippi State, MS Introduction Ants in the genus Camponotus (Formicidae: Formicinae) are among the largest ants in North America. They are collectively known as carpenter ants because some species nest in wood, including man-made structures. As a result, several species are important economic pests. There are 50 species of Camponotus reported from the United States (Hanson & Klotz, 2005), but only 20 are known to occur east of the Mississippi River. In Mississippi, much of our data on ant distributions in the state are from surveys by Marion Smith in the 1920's and early 1930's (Smith, 1923; 1924a,b,c; 1927; 1928a,b; 1931; and 1932). Smith reported 17 species of Camponotus from the state, of which only 13 are now considered to be valid species. Smith's collections of ants from the state were limited, and therefore, the distributions of Camponotus species throughout Mississippi are not clearly understood. Although Camponotus species are large ants, they are often very difficult to identify due to wide morphological variation. Scattered keys to species in various subgenera are available, but comprehensive identification keys to Southeastern species of Camponotus have not been published. Consequently, it is difficult to accurately identify carpenter ants in this area.Methods Since 2001, the Mississippi Entomological Museum (MEM) has been conducting surveys of ants in Mississippi to provide baseline data on diversity and distributions of native species. Collections were made using a variety of methods including pitfall traps, Lindgren funnel traps, blacklight traps, malaise traps, baiting, soil and litter sampling, tearing apart rotting logs and trees, and visual searching for ants and nests. Specimens were collected and stored in 90% ethanol, with representatives pinned and labeled. Species determinations were made using a combination of existing keys, comparisons with identified material, information gleaned from original descriptions, biological observations, morphological examinations, and through correspondence and cooperation with other experts in Formicidae. Results Results Recent surveys, coupled with older museum specimens and literature records, have resulted in the collections or records of ants from every county and physiographic region of Mississippi. As a result of the intensive collecting done during the last 4 years, a clearer picture of the distribution and habits of Camponotus is now known. Fifteen species of Camponotus in 5 subgenera are now known to occur in the state including Camponotus americanus Mayr, C. caryae (Fitch), C. castaneus (Latreille), C. chromaiodes Bolton, C. decipiens Emery, C. discolor (Buckley), C. floridanus (Buckley), C. impressus (Roger), C. mississippiensis Smith, C. nearcticus Emery, C. obliquus Smith, C. pennsylvanicus (DeGeer), C. snellingi Bolton, C. socius Roger, and C. subbarbatus Emery (new state record). A list of Mississippi Camponotus species is being prepared with brief descriptions, information on biological and economic importance, distributional maps, identification keys, habitus photos, and diagnostic drawings. Additional information is available on the MEM Formicidae of Alabama and Mississippi website at: archtaxapages/Formicidaehome.html. Literature Cited Hansen, L. D., and J. H. Klotz Carpenter ants of the United States and Canada. Cornell University Press. Ithaca, N. Y. i-xii+204 pp. Smith, M. R Two new Mississippi ants of the subgenus Colobopsis. Psyche 30: Smith, M. R. 1924a. An annotated list of the ants of Mississippi (Hym.). Entomological News 35: Smith, M. R. 1924b. An annotated list of the ants of Mississippi (Hym.). Entomological News 35: Smith, M. R. 1924c. An annotated list of the ants of Mississippi (Hym.). Entomological News 35: Smith, M. R An annotated list of the ants of Mississippi with a description of a new species of Pheidole (Hym.: Formicidae). Entomological News 38: Smith, M. R. 1928a. An annotated list of the ants of Mississippi with a description of a new species of Aphaenogaster (Hym.: Formicidae). Entomological News 39: Smith, M. R. 1928b. An annotated list of the ants of Mississippi with a description of a new species of Aphaenogaster (Hym.: Formicidae). Entomological News 39: Smith, M. R An annotated list of the ants of Mississippi (Hym.: Formicidae). Entomological News 42: Smith, M. R An additional annotated list of the ants of Mississippi (Hym.: Formicidae). Entomological News 42: Figures 1-7. Profile views of Camponotus spp. workers. 1) Camponotus americanus Mayr, 2) C. castaneus (Latreille), 3) C. chromaiodes Bolton, 4) C. pennsylvanicus (DeGeer), 5) C.impressus (Roger), 6) C. obliquus Smith, 7) C. mississippiensis Smith. Scale bars equal 1.00 mm. Figures Profile views of Camponotus spp. workers. 8) Camponotus nearcticus Emery, 9) C. caryae (Fitch), 10) C. decipiens Emery, 11) C. discolor (Buckley), 12) C. snellingi Bolton, 13) C. subbarbatus Emery, 14) C. floridanus (Buckley), and 15) C. socius Roger. Scale bars equal 1.00 mm. Figures Frontal views of heads of Camponotus spp. workers. 16) Camponotus americanus Mayr, 17) C. castaneus (Latreille), 18) C. chromaiodes Bolton, 19) C. pennsylvanicus (DeGeer), 20) C. impressus (Roger), 21) C. obliquus Smith 22) C. mississippiensis Smith; angled views of heads of 23) C. impressus, 24) C. obliquus, and 25) C. mississippiensis. Scale bars equal 1.00 mm. Figures Frontal views of heads of Camponotus spp. workers. 26) Camponotus nearcticus Emery, 27) C. caryae (Fitch), 28) C. decipiens Emery, 29) C. discolor (Buckley), 30) C. snellingi Bolton, 31) C. subbarbatus Emery, 32) C. floridanus (Buckley), and 33) C. socius Roger. Scale bar equals 1.00 mm. Maps Distributions of Camponotus species in MS. 1) C.americanus,2) C. caryae, 3) C. castaneus, 4) C. chromaiodes, 5) C. decipiens, 6) C. discolor, 7) C. floridanus, 8) C. impressus, 9) C. mississippiensis, 10) C. nearcticus, 11) C. obliquus, 12) C. pennsylvanicus 13) C. snellingi, 14) C. socius, and 15) C. subbarbatus.