Subfamily FORMICINAE
Tribe CAMPONOTINI

Camponotus (Colobopsis) mississippiensis Smith

Camponotus mississipiensis, profile view of major worker. Note the sharp edged rim formed where the head is truncated.
Camponotus mississipiensis, profile view of a minor worker.
Camponotus mississipiensis, a major worker standing near the entrance hole to its nest. (photo by Ross Hutchins)

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 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 obvoius and deep metanotal suture have the shape of the alitrunk in a smoothly curved arc (as seen in profile). 

Camponotus mississipiensis is in the subgenus Colobopsis. This subgenus can be distinguished from other carpenter ants by the unusual modifications of the heads of both the major workers and queens which are severely truncated in the anterior third. This phragmotic condition enables the major workers to serve as living doors to their nests which are in living or dead twigs, stems, and some galls.

C. mississipiensis is a relatively small carpenter ant with major ranging from 4.5 to 5.5 mm and minors 3.5-4.0 mm. C. mississipiensis (major workers) can be easily recognized by the deeply concave, truncated surface of the head with the sides of the truncated area very sharp and well defined except in the posterior part of the clypeus. When viewed from above, the head of majors of this species have sides that diverge anteriorly and have the anterior part of the head very concave or hollowed out.

Camponotus mississipiensis appears to be the most common species of the subgenus Colobopsis found in Mississippi and in fact was so named for that reason. This highly specialized species has only been found nesting in live twigs of white ash, Fraxinus americana L. (Smith, M. R. 1923; Tynes 1964) and generally, if one can find the host tree, one can find colonies of this ant.

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