Red harvester ants
Most recently reviewed by: David Kerns (2018)
Common Name(s): Red Ant, Red Harvester Ant
Description
Red harvester ant workers are 1/4 to 1/2-inch long and red to dark brown. They have large, square heads, elbowed antennae, large mandibles and no spines on the body. Their mounds or nests are distinctive. Usually there is no vegetation within a 3 to 6 feet circular around the central opening of their colony and along foraging trails radiating from the colony. The bare ground surrounding the entrance hole is often covered with small pebbles excavated from the tunnels within the nest. Near the entrance hole there will be a midden, which serves as a trash dump where, pebbles, dead ants, and other discarded waste accumulates.
Origin and Distribution
There are hundreds of harvester ant species world wide, with 22 species of harvester ants in the United States, and 12 within the state of Texas. Species exist throughout much of the United States, Canada and Mexico.
Red harvester ants, Pogonomyrmex barbatus, are common in Texas, but have suffered decline in much of the state due to red imported fire ant. Red imported fire ant generally do not prey upon harvester ants, but out compete them for resources.
Worker ants can bite and produce a painful sting but are generally reluctant to sting. Based on the Schmidt sting pain index, red harvester ants rate a pain level of 3 on the 1-4 scale (Schmidt et al. 1983, Schmidt 1990). Effects of the stings can spread along lymph channels and may be medically serious.
Habitat & Hosts
Although some species of harvester ant prefer wooded environments, the red harvester ant prefers open grasslands, especially areas with clay loam soils. They are common along the edges of dirt roads. Red harvester ants are most active during hot, dry conditions.
Red harvester ant foragers collect grass seeds and store them in their nests. Their foraging range is typically 25-30 m2 {250 to 300 ft}(Gordon 1995). They use their large mandibles to grind seeds into a “bread” like material which they store in their nests in area termed “granaries”. In addition to seeds, dead insects are also collected for food.
They are a favorite food source of horned lizards. Worker harvester ants are often collected or sold as inhabitants of ant farms.
Life Cycle
A colony of harvester ants live for 15-20 years and reach reproductive and stable colony size of about 12,000 workers at approximately 5 years (Gordon 1995). Mating occurs from spring to fall each year, but generally follows summer rains (Davis 2016). Winged males and females swarm, pair and mate. Males soon die and females seek a suitable nesting site. After dropping her wings, the queen ant digs a burrow and produces a few eggs. Larvae hatch from eggs and developed through several stages (instars). Larvae are white and legless, shaped like a crookneck squash with a small distinct head. Pupation occurs within a cocoon. Worker ants produced by the queen ant begin caring for other developing ants, enlarge the nest and forage for food.
Management
If you live in the State of Texas, contact your local county agent or entomologist for management information. If you live outside of Texas, contact your local extension for management options.Red harvester ants are not considered serious agricultural pests and they do not invade homes or structures. Most people encourage establishment of red harvester ant colonies but because of their painful sting and habit of clearing vegetation around their nests, some nests may require removal. Over-the-counter ant baits are general effective in eliminating unwanted red harvester ant nests.
Citations
Davis, J.M. 2016. Management of the red harvester ant Pogonomyrmex barbatus. https://tpwd.texas.gov/huntwild/wild/wildlife_diversity/texas_nature_trackers/horned_lizard/documents/harvester_ant_ management.pdf.
Gordon, D. M. 1995. The development of an ant colony’s foraging range. Anim. Behav. 49: 649-659.
Schmidt, J. O., Blum, M. S., Overal, W. L. 1983. Hemolytic activities of stinging insect venoms. Archives of Insect Biochemistry and Physiology. 1 (2): 155–160. doi:10.1002/arch.940010205
Schmidt, J. O. 1990. Hymenoptera venoms: striving toward the ultimate defense against vertebrates. In D. L. Evans; J. O. Schmidt. Insect defenses: adaptive mechanisms and strategies of prey and predators. Albany, New York: State University of New York Press. pp. 387–419.
