Ants are not all created equal. There are many species in Texas, and it just takes some persistence and knowing what to look for to tell them apart. Most people think that only fire ants are around. But if you look closely and take time to learn a little ant biology, the ant world can be a captivating place.
About 270 species of native and imported ants have been identified in Texas, according to Dr. Brad Vinson, professor of entomology at Texas A&M University. A few are destructive — such as leaf cutter ants that devour greenery and carpenter ants that destroy wood in a home. However, most native ants cause no problems and may even be desirable to have around, Vinson said.
Red imported fire ants are real pests, with few natural enemies in the United States. But some other ant species are in constant competition with the imported fire ants and may even help humans in the war against this invading species.
“To get rid of all ants outside just because they are there is not the solution,” Vinson said.
Ants that compete with fire ants are sometimes difficult to identify, but once their characteristics and habitats are revealed, most are easy to spot — and perhaps even can use them to our advantage against imported fire ants. Unfortunately, when very abundant, some of these ants also can be a nuisance to people. Some common competitor ant species are:
• PYRAMID ANT (Dorymyrmex spp.). A small ant about 1/8″ long. The key identifying feature is a pyramid-shaped projection on top of the thorax. These ants are red-black or dark brown. They build nests in open, sunny areas. The workers deposit the soil in a circular crater or mound around the entrance hole and are usually 2″ to 4″ in diameter. These mounds are usually located near the nests of other ants, particularly harvester ants. The colonies also can be found under decorative rocks and logs. Workers move quickly and forage in trails. They feed on other insects and are fond of the honeydew that aphids and scales produce.
• LITTLE BLACK ANT (Monomorium minimum:). A very small, black ant closely related to the Pharaoh ant (an indoor pest ant). It nests in soil under rocks, logs or debris. It also builds nests in open areas of soil in lawns. The nests in the ground are small craters of very fine soil. These ants’ colonies also are found under the bark of trees, in debris trapped in the crotches of trees, in wood damaged by termites, in firewood piles and in stacks of bricks and stones. Little black ants feed on a wide variety of foods, including live and dead insects and the honeydew produced by aphids. The ants are active foragers and forage in trails of a few or up to hundreds of workers. These trails can be located along sidewalks and foundations and up the sides of buildings.
• CRAZY ANT (Paratrechina longicornis:). These are small, dark gray to black ants that are easily recognized by their extremely long legs and antennae. Crazy ants get their name from their habit of running about very erratically with no apparent sense of direction. Colonies most often can be found living in soil, under items such as logs, stones, landscape timbers, wood, debris and above-ground swimming pools. Crazy ants feed on a wide variety of foods, including other insects, grease and sweets. They have been known to feed on the larvae of fleas and flies, and also have been observed carrying away fire ant queens immediately after a swarm.
• BIG-HEADED ANT (Pheidole spp.). Big headed ants have two sizes of workers — major workers (soldiers) and minor workers. Major workers have a very large head in proportion to their bodies. Big-headed ants are most often confused with fire ants, but imported fire ants do not have workers with larger heads. Big-headed ants usually nest in the soil in protected locations such as under rocks, logs, firewood, patio blocks and landscape timbers, although they will nest in open areas of soil. They typically feed on live and dead insects, seeds and the honeydew produced by insects such as aphids and scales. They are considered major predators of fire ant queens, which are present in large numbers after a fire ant swarm.
The most dreaded for Texans is the red imported fire ant. However, it’s important not to confuse the imported fire ant with native fire ants or other species, Vinson said.
Imported fire ants are medium-sized ants — from 1/16″ to 1/4″ long. They build mounds only up to 18″ in diameter. However, for what they lack in size, they make up in sheer numbers. Mound densities range from 20 to 80 per acre for single queen colonies and from 100 to more than 1,000 per acre for multiple-queen colonies.
An identifying characteristic of imported and native fire ants is their aggressive nature: They will run up a stick if it is put into a mound.
For more information about ant identification, visit the Web at http://fireant.tamu.edu. Look for fact sheet #10, “Texas Pest Ant Identifcation,” for the illustrated key or the slides under “materials” and “images.”
* Information for this article was taken from Structure Infesting Ants by Stoy A. Hedges.