Ghost Ants, Part I

Are there ghosts in your future?

Ghost ants (Tapinoma melanocephalum) feeding on food scrap.
Ghost ants (Tapinoma melanocephalum) feeding on food scrap.
iStock | Víctor Suárez Naranjo

Editor’s Note: The following article was adapted from Techletter, with permission from Pinto & Associates.

The ghost ant (Tapinoma melanocephalum) is one of a growing number of exotic insects emerging as pests in the United States and Canada. Tropical in origin, this ant is now a major pest in Florida and Hawaii, in Puerto Rico and the Caribbean Islands. It's also a pest in coastal areas of Texas. In these warm locations, the ghost ant infests both indoors and outdoors.

But you're not immune if you work in other areas. Infestations of ghost ants have been found inside heated buildings in many states in the U.S. and as far north as Manitoba, Canada. Stay alert! It seems likely that many indoor ghost ant infestations in colder climes are missed because the ants are being misidentified as odorous house ants, pharaoh ants, and other small ants.
 
Ghost ants are tiny "one-node" ants, about 1/16-inch long (1.3-1.5 mm), smaller even than Pharaoh ants. They are so-named because of their unique coloration: the head and thorax are black (hence the species name: melano = black; cephalum = head) but the rest of the body is transparent. When a ghost ant walks across a light-colored surface, all you see is its dark head and thorax, while on a dark surface you see a pale, ghostlike shape. The ants tend to move erratically. Their "ghostlike" bodies are especially difficult to see in low light. Workers have the smell of rotting coconuts when crushed.
 
Biology and Dispersal

The ghost ant is considered a "tramp" ant, an ant with the proven ability to hitchhike around the globe. Colonies are transported in commercial shipments of house plants, fresh produce, and cut flowers. People also unknowingly carry ghost ants home in luggage, clothing, and all kinds of household goods, including laptop computers!

A colony can be large and can consist of many small individual nests, each with 100 to 1,000 workers and multiple queens. Workers sometimes move from one nest to the other following odor trails.
 
Ghost ant colonies spread locally by budding. Queens often simply walk to a new nest site accompanied by a group of workers. They move readily, sometimes nesting in a site for only a few weeks. Like Pharaoh ants, ghost ants can end up with many small nests throughout a building, particularly if disturbed by ineffective insecticide sprays.
 
Ghost ants are omnivores, meaning they eat almost anything: dead and live insects, human food waste, pet food, and especially sweets. Fond of honeydew, they tend insects like aphids who feed on plant juices. Ghost ants often trail to a water source.
 

Ghost Ants, Part II, will discuss how to inspect for ghost ants and will provide recommendations for their control.

The authors are co-owners of Pinto & Associates.