Photographer:Eli Sarnat Affiliation:USDA APHIS ITP Source:www.bugwood.org Copyright: CC BY-NC 3.0
Adult Description: The Ghost Ant (Tapinoma melanocephalum) is extremely small, 1.3 to 1.5 mm long and monomorphic (one-sized). They have 12-segmented antennae with the segments gradually thickening towards the tip. The head and thorax are deep dark brown with opaque or milky white gaster and legs. The thorax is spineless, and the gaster (swollen part of abdomen) has a slit-like anal opening which is hairless. Stingers are absent. Their small size, combined with the pale color, make ghost ant workers hard to see. In fact, the ghost ant may not look ant-like on casual inspection. This species runs in quick, erratic movements when disturbed, but sometimes can be found trailing, where movement is more slow and deliberate. On close inspection some trailing workers can be seen carrying brood (larvae and pupae). Workers may emit acrid (coconut-like) odor when crushed. This pungent odor is where the ants gain the name "Corspe Ant" in Malaysia.
Larva Description: Small, white, typical ant larvae.
Host Plant: None
Ghost ants, like many other invasive pest species, are able to re-distribtute themselves quickly and effectively due to myriad factors, first and foremost being their polygyny nesting strategy. Further, colonies can become so large that they overlap, which may lead to enormous, sprawling nest sites with thousands and possibly millions of individuals. Further, the ghost ant invaders compete with indigenous ant species for a limited supply of resources. Their efficiency in gathering resources and expanding at explosive rates allows Ghost ants to out-compete local species, effectively driving them from their native areas. This leads to a decrease in local fauna which may become detrimental to the ecosystem.
The ghost ant is highly adaptable in its nesting habits. It nests readily outdoors or indoors. Colonies may be moderate to large in size containing numerous reproducing females (polygyny). Generally, the colonies occupy local sites that are too small or unstable to support. These sites include tufts of dead but temporarily moist grass, plant stems, and cavities beneath detritus in open, rapidly changing habitats. Indoors, the ant colonizes wall void or spaces between cabinetry and baseboards, and thus is a common indoor pest species.
Multiple queens may be spread out in multiple subcolonies. New colonies are probably formed by budding. This occurs when one or more reproductive females, accompanied by several workers and possibly some brood (larvae and pupae) leave an established colony for a new nesting site.
Workers have the habit of running rapidly and erratically when disturbed. They are fond of honeydew and tend honeydew-excreting insects. They also feed on both dead and live insects.
The ghost ant is associated with a complex of ant species known as "tramp ants" that is widely distributed in tropical and subtropical latitudes worldwide. Colonies of T. melanocephalum are reported from such isolated locations as the Galapagos Islands. In temperate latitudes, the ghost ant can establish in greenhouses and other buildings with favorable conditions, even as far north as Winnipeg, Manitoba, Canada. Ghost ant populations and infestations are reported in many areas of the United States, as well as in Canada, Puerto Rico and the Caribbean Islands.
In the United States, the ghost ant is well established in Florida and Hawaii, and its range is expanding. The ant reached Texas in 1994 or 1995, probably through Galveston on a shipment of plants from Florida. While weak to the cold, the ghost ant is still able to distribute itself widely among warmer states.
Old World Tropics. It is unknown if the Ghost ants are native to Asia or Africa.
U.S. Habitat: This species usually nests in disturbed areas, flowerpots, under objects on the ground, under loose bark, and at the bases of palm fronds. Indoor nests occur in small spaces such as cracks, spaces between books, or wall voids. This is a very common pest inside homes.
U.S. Present: Ghost ant populations and infestations have been reported in many areas of the United States, as well as in Canada, Puerto Rico and the Caribbean Islands. This is a warm-weather species, with breeding populations already established in Florida and Hawaii, but has also been found in nothern areas living in greenhouses.
Texas: This ant was first discovered in Texas in 1994 and has probably established a breeding population since that time.
While it is usually not confused for with the Pharaoh ant (Monomorium pharaonis), the Ghost ant does nest in a similar manner. This species is much too small to be accurately identified without a microscope.
Colonies of ghost ants are highly mobile and frequently move from overpopulated nests. They are difficult to eradicate. When a colony is located, a contact insecticide may be sprayed to kill it, but a colony can be comprised of many nests, and killing only the workers is a temporary solution. The best management tactic is the use of baits. These ants favor sweets. Boric acid (1-5%) in a sugar or honey water solution seems to work well. Few studies have been conducted regarding Ghost Ant control.
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References
Chenault, EA. 1997. Ghost ants now in Texas. Texas A&M Agriculture News.
Gomez-Nunez JC. 1971. Tapinoma melanocephalum as an inhibitor of Rhodnius prolixus populations. Journal of Medical Entomology 8: 735-737.
Haack KD, Granovsky TA. (1990). Ants. In Handbook of Pest Control (Story K, Moreland D. (eds.)). Franzak & Foster Co., Cleveland, OH. pp. 415-479.
Smith MR. 1965. House-infesting ants of the eastern United States; their recognition, biology, and economic importance. USDA-ARS Technical Bulletin 1326. 105 pp.
Wheeler WM. 1910. Ants, their structure, development and behavior. Columbia University Press. New York and London. 663 pp.
Internet Sources:
http://entnemdept.ufl.edu
http://flrec.ifas.ufl.edu
http://urbanentomology.tamu.edu
http://www.issg.org
http://www.itis.gov
Experts:
Dr. Jerry Cook - Sam Houston State University - jcook@shsu.edu
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