Types of Ants :: Big-headed Ants :: Printer-Friendly Version
Ant Origin & Distribution
There are a number of different species of big-headed ants found in the United States. Not all are considered to be pests. Some are native to the U.S., while others have been introduced from other parts of the world. For instance, one of the more common species, Pheidole megacephala, is thought to have originated in southern Africa. Although found throughout much of the country, big-headed ants are pests primarily found in warmer areas of the country in both arid and humid climates. They have become common pests in central and southern Florida and are considered an important invasive pest in Hawaii.
Ant Identification
Depending on the species, workers of big-headed ants vary in color from shades of light to dark brown, reddish brown or light yellow. Some species are more uniform in color while others have areas of different coloration. The workers are dimorphic, which means they have two sizes—minor workers and major workers. The size range for minor and major workers varies by species. For one of the more common pest species, Pheidole megacephala, minor workers are small ants about 1/10" in length and the major workers are about 1/8" in length. The minor workers' body regions are proportionate in size whereas the major workers' heart-shaped head is disproportionately larger than the rest of the body. The minor workers are more commonly seen than the major workers.
Ant Biology
Colony size of big-headed ants varies by species and may range from several hundred to many thousands of individuals. Most species have multiple queens, although some species have single queen colonies. For example, the species Pheidole megacephala has multiple queens and can form large super colonies of interconnected nests that can cover multiple residential lot areas. These super colonies are formed primarily by budding, a process in which queens from one nest site leave with a few workers to form new nests. Many species of big-headed ants also form new colonies by mating flights of winged ants (called alates or swarmers) usually in mid-summer.
Big-headed ants nest in soil, usually in protected areas such as under stones, pavers, logs or other debris. Nests are also found in potted plants and next to and under concrete slab foundations. Sometimes piles of soil are found indoors along expansion joints and baseboards. This is soil that has been excavated by ants building a nest under the slab foundation. Some species nest within the cracks, crevices and voids of walls, fences and bark of trees. Nests have also been found in rotting wood and in old termite damaged wood in structures.
Ant Habits
Big-headed ants may be seen trailing along edges of foundations, driveways, sidewalks and other structural guidelines. They may construct mud tubes on foundations and other structures protecting their trails and entry areas. The tubes may be mistaken for termite mud tubes but are more fragile. Indoors, these ants may be seen trailing along baseboards and under carpet edges. Often these trails are from outdoor nests. Big-headed ants are omnivorous, feeding on seeds, living and dead insects, and honeydew from sap sucking insects. The large head and mandibles of the major workers are useful for feeding on seeds and hard exoskeletons of insects, as well as for defense. Indoors, big-headed ants will feed on fats, meats, oily foods such as peanut butter and sweet foods.
Ant Control
If you think you might have a big-headed ant infestation in your home, it's imperative that you contact a certified and licensed pest control professional
to inspect the situation and confirm identification. Experts will advise against do-it-yourself options, as it is much more efficient and cost-effective to have a trained set of eyes identify the correct ant species and recommend effective treatment options specific to an individual infestation. Improper do-it-yourself options may result in killing a few ants, while the rest of the colony simply relocates to other areas around and inside the structure.