The dark rover ant is one of several species of rover ants present in the United States, both native and introduced. It is native to South America, where it survives well in a variety of habitats, especially urban and suburban areas. Although introduced to the U.S. as early as 1976 in Louisiana, it didn’t become widely reported as a structural pest until the early 2000s. It is now mostly found in South Carolina, Georgia and the Gulf states, as well as some urban centers in Arizona and southern California.
Dark rover ant workers are tiny (about 1/16th of an inch), all the same size, and range in color from light to dark brown. They tend to nest in soil at the base of trees, under leaf litter or mulch, or other objects lying on the ground. Colonies have one queen and reproduce with mating flights. Interestingly, they often coexist with other pest ants, such as Argentine ants, tawny crazy ants, and fire ants. Like tawny crazy ants, they defend themselves from fire ant venom by neutralizing it with formic acid they spread on their bodies.
Dark rover ants may also nest in structural voids and are mostly a nuisance when workers or winged reproductives enter a structure. They seem to require high moisture and may be more of a problem in kitchens and bathrooms, and structures with irrigated lawns. Since they prefer to eat liquid carbohydrates, baiting indoors with a sweet bait can be effective. A residual spray around structures can also reduce the amount of foraging workers.