Common House-Invading Ant Species

The species of ants that plague your customers are largely dependent on your geography. In Florida, for example, you may encounter a broad range of ant species – among them, Pharaoh, white-footed, Argentine, ghost, pyramid, carpenter, rover, native fire, imported fire, crazy, thief, Caribbean, acrobat and bigheaded ants, says Dr. Philip Koehler, professor of urban entomology at the University of Florida.     

 

In the Northeast, you are more likely to get calls from homeowners about carpenter, odorous and pavement ants. In fact, these three species topped the list of problematic species when PMPs from across the nation were polled in the recent State of the Ant Market Survey conducted by PCT and Readex Research. 

 

But don’t get comfortable thinking you have your region’s ant challenges pegged just yet: Geographic lines keep blurring as tramp species continue to spread. Dennis Mastrolia of Dennis the Mennis in Lynn, Mass., says he treats a variety of ants you might not expect so far north. “We see a lot of carpenter, pavement and Pharoah ants, for sure,” he says, “but from time to time, we’ll also encounter Argentine, acrobat and even some crazy ants.” 

 

It’s critical to know the difference between species so you can treat them effectively. Following are a few of the ant species known to infest homes, along with some of the characteristics and behaviors that can help you identify them and locate their nests.

 

Acrobat Ants – Named for their tendency to raise and arch their abdomen above the head and thorax when alarmed, acrobat ants vary in color from yellowish brown to brown, to red and black, to black. Infestations often originate from a nest outside in a tree, stump or log. Indoors, they nest in woodwork, particularly door or window frames that have been damaged by insects or moisture, and sometimes infest foam core panel insulation. They feed on live and dead insects, and honeydew.

 

Argentine Ants – Known for creating supercolonies with numerous queens and hundreds of thousands of workers, Argentine ants are light to dark brown with lighter legs and yellowish mandibles. They typically nest outdoors beneath boards, stones or concrete; within decaying plant matter and mulch; and at the base of plants or trees infested with homopterans. Indoors, look for nests in wall voids, bath traps and insulation. Argentine ants eat honeydew and small insects.

 

Bigheaded Ants – Bigheaded workers can be identified by their unusually large, heart-shaped heads on bodies that can range in color from dark brown to red to light yellow. Colonies can reach tremendous size, with huge extended nests and multiple queens. Most species nest in soil, and can be found around buildings, ornamental plant bases, sidewalks and driveways. They are often moved indoors in potted plants. They feed on a variety of foods, but usually prefer insects, seeds and honeydew. Peanut butter can be used to attract the majors.

 

Carpenter Ants – These large ants establish colonies by excavating decayed or damaged wood, creating smooth tunnels and galleries. Mature colonies consist of a parent nest – usually located in tree, stump, stack of firewood or landscape timbers – and satellite nests, which can be found in similar sites in neighboring trees or indoors in attic rafters, insulation, roof overhangs, bay windows, fascia boards, floor joists, box headers, wall voids, hollow curtain and shower rods, hollow doors or columns, or behind dishwashers, under cabinets or in ceiling voids. Carpenter ants feed primarily on protein and carbohydrates.

Crazy Ants – Workers are known for their extraordinarily long legs and antennae, and for their erratic, jerky movements. Colonies have, on average, 2,000 workers and eight to 40 queens. Outdoors, they nest in trash, plants, rotted wood and soil, often adjacent to landscape mulch or behind thick vegetation. Indoors, look in wall voids, under carpeting and in potted plants. Crazy ants are omnivores, feeding on honeydew, live and dead insects and various household foods, especially sweets.

 

Ghost Ants – Also known as black-headed ants, ghost ants have dark heads and thoraxes with light, almost translucent abdomens and appendages. Found in warm, humid habitats, they nest in soil and rotting wood, under bark, within leaf litter and in plant cavities. Look for them in soil next to foundations, porches, shrubs and trees. Inside, nests are likely to be in potted plants, breadboxes and shower curtain rods, behind baseboards and between cabinets. They prefer to forage on sweets, but will also feed on grease. Ghost ants feed on live and dead insects and tend homopterans for honeydew, a sugar-rich sticky liquid secreted by aphids and some scale insects as they feed on plant sap.

 

Little Black Ants – These shiny, tiny dark brown to black ants are common in wooded habitats. Infestations can usually be traced to a stump, tree, log, fence or a pile of lumber or bricks. They also nest in landscape mulch and under stones. In the house, look for little black ant nests in wall voids and cabinets, and within and behind foundations and brick or stone veneer. They feed on insects, honeydew, plant exudates, pollen, hatchling birds and bird feces. Indoors, they will eat sweets, meats, grease, bread, oils, cornmeal, fruit and fruit juices.

 

Odorous House Ants – Named for the strong smell of rotten coconuts emitted when crushed, the odorous house ant is uniformly brown or black. Its colonies may have multiple queens and multiple nest sites; the number of sites varies seasonally, with fewer in winter and more in warmer months. The ants nest in soil often beneath board or stone or in and around stacked lumber, bricks, firewood, rocks or cardboard. Indoors, look for nests near moisture, such as within wall voids near pipes and heaters, bath traps or damaged wood, and under toilets. Workers forage day and night to collect honeydew. They also feed on living and dead insects. They prefer sugars and protein over lipids with no seasonal shift.

 

Pavement Ants – Predictably, pavement ants make their nests beside or under sidewalks, driveways and foundations. They are slow-moving brown or black ants that often leave conspicuous piles of excavated soil when they nest outside. During winter, they move inside, usually to be near a heat source, such as a radiator or heating duct. Nests are typically at ground level, and workers travel along pipes or wires. They are more active at night. Pavement ants feed on live and dead insects and tend homopterans for honeydew, a sugar-rich sticky liquid secreted by aphids and some scale insects as they feed on plant sap. 

Pharaoh Ants – Often confused with thief ants due to their small size and color (look for a difference in antennae: Pharoahs’ antennae are 12-segmented with a three-segmented club; thief ants, 10-segmented with a two-segmented club), Pharaoh ants are a tramp species appearing throughout the world, thanks to international trade. Yellowish or light brown to reddish with a darkened gaster tip, these ants are predisposed to satellite nesting and can forage long distances from the nest. Look for nests in cracks and crevices with warmth and high humidity; in kitchens and bathrooms near water sources; and in wall voids, under floors and behind baseboards or window sills. These omnivores forage all day and night for fats, proteins and carbohydrates.

 

Thief Ants – Nesting close to other ant nests so they can steal food and prey upon brood, brown or yellow thief ants nest in exposed soil and under rocks or rotting wood. Indoors, they nest in woodwork and masonry, using electrical wires in wall voids to move from room to room. They prey upon fire ant queens and other insects, and feed on seeds and vegetables.

 

White-footed Ants – Black with yellow feet, these ants have been known to short-circuit air conditioners and other electronics.  They nest mainly outdoors, in or near trees or in the soil, loose mulch or leaf litter. When they do nest indoors, they are likely in wall voids or attics. They prefer sugars and proteins.