Subfamily DOLICHODERINAE
Tribe DOLICHODERINI

Tapinoma melanocephalum (Fabricius)

Tapinoma melanocephalum, full face view of worker (click photo to enlarge).
Photo courtesy of http://www.antweb.org/
Tapinoma melanocephalum, profile view of worker (click photo to enlarge).
Photo courtesy of http://www.antweb.org/
Tapinoma melanocephalum, full face view of worker (click photo to enlarge).
Tapinoma melanocephalum, profile view of worker (click photo to enlarge).
Tapinoma melanocephalum drawing by Joe MacGown
Tapinoma melanocephalum, profile view of worker - drawing by Joe MacGown (click image to enlarge)
Scale bar equals 1.0 mm

Introduction
Tapinoma melanocephum (Fabricius), commonly called the ghost ant, is an exotic tramp species thought to have originated in either Afro tropical regions or Asia (Smith, 1965). The ghost ant is considered to be a nuisance species that invades houses, buisnessess, where it may nest and get into food stores.

Identification
Ghost ant workers can be easily identified by their extremely small size and coloration.  Workers are monomorphic and are only 1.3 to 1.5 mm in total length.  They are bicolored with the head and mesosoma being dark brown to blackish brown and the appendages, petiole, and gaster being milky white.  They have 12-segmented antennae, lack spines, lack a stinger, lack large erect hairs on the body, and lack a protruding node on the petiole.  The petiole is often hidden by the gaster, which may overlap it.  These minute ants are difficult to spot because of their size and partial light coloration. 

Biology and Economic Importance
Ghost ants are known to nest both indoors and outdoors, with colonies being small to large and having multiple queens.  They are opportunistic colonizers, and queens from one colony may be spread out in smaller subcolonies.  Outdoors, they nest in a variety of places such as in disturbed areas, plant pots, under objects on the ground, under bark, at bases of palm fronds, or other similar situations, and indoors they nest in wall voids or potted plants (Nickerson and Bloomcamp, 2006).  This species does not sting or bite, but is considered a nuisance pest in houses as it invades food stores, especially sweets such as sugar and syrup (Smith, 1965).

Distribution
Due to its spread by commerce, it is now widespread in subtropical and tropical regions.    In the U.S. it is only known to be established in outdoor conditions in Florida, Hawaii, southern Texas, and most recently it has been discoverd in outdoor situations in southern Mississippi (MacGown and Hill, 2009). Additionally, it has been reported in heated buildings or greenhouses in some northern states and even in Canada. 

Literature Cited
MacGown, J. A. and J. G. Hill.  2009. Tapinoma melanocephalum (Hymenoptera:  Formicidae), a new exotic ant in Mississippi.  Mississippi Academy of Sciences 54: 172-174.  [pdf]

Nickerson, J. C. and C. L. Bloomcamp. August 2006.  Featured Creatures:  Tapinoma melanocephalum (Fabricius) (Hymenoptera:  Formicidae). http://creatures.ifas.ufl.edu/urban/ants/ghost_ant.htm Accessed 5 May 2008.

Smith, M. R. 1965. House-infesting ants of the Eastern United States, their recognition, biology, and economic importance. United States Department of Agriculture, Technical Bullitin No. 1326: i-105

Links

AntWeb Images
Discover Life Images

Featured Creatures-Tapinoma melonocephalum- http://creatures.ifas.ufl.edu/urban/ants/ghost_ant.htm

Center for Urban & Structural Entomology, Texas A&M-Ghost Ant,Tapinoma melonocephalum- http://urbanentomology.tamu.edu/ants/ghost.cfm