Fire Ant Identification

Ants are social insects. The nest or colony can be found indoors and outdoors, although some species have preferred nesting sites. The nest contains one or more queen ants which lay eggs and are cared for by worker ants. Worker ants are sterile or non-reproductive female ants that tend the queen, the brood (eggs, larvae and pupae), and forage for food. Most species produce winged ants, called reproductives, during certain times of the year. These are male and female ants leaving the nest to mate and establish new colonies. When winged ants swarm in the home, there is a likelihood that their colony is located somewhere inside. Distinguish winged ants from termites using the following characteristics (also see Extension publications B-6080, Subterranean Termites and L-1782, Drywood Termites:

Winged ants
Winged termites
  • two pairs of wings, hind wings shorter
  • elbowed antennae
  • narrow “waist” between abdomen and thorax
  • two pairs of wings of equal size and shape
  • hair-like antennae
  • no narrow waist

Ants belong to the insect order Hymenoptera and the family Formicidae. Over 250 species occur in Texas. Most species are not considered to be pests. Although some other insects mimic ants and superficially resemble them, distinctive features of Formicidae include the narrow section between the thorax and abdomen called the pedicel of the metasoma. This section has one or two segments and has an upright lobe (Borror et al. 1989). In addition, antennae are generally elbow-shaped. Ants are, for the most part, true social insects (eusocial) and colonies contain a queen or queens, winged reproductive male and female ants and wingless sterile female worker ants. Species occurring in turf vary from region to region. There are seven subfamilies of Formicidae, and some of those commonly reported from turfgrass are from two subfamilies, including:

1) Subfamily Myrmicinae (antennae ten-segmented with a two-segment club): the fire antsSolenopsis spp.; the harvester antsPogonomyrmex spp.; the pavement ant,Tetramorium caespitum L.; the pyramid antsDorymyrmex (Conomyrmainsana(Buckley); and the Texas leafcutting antAtta texana (Buckley); and,

2) Subfamily Formicinae: the cornfield antLasius alienus (Foerster); the Allegheny mound antFormica exsectoides Forel; and the red antFormica pallidefulva Latreille. The fire ants are by far the most important and common pest ants of turfgrass areas in the southeastern states. Native fire ants include Solenopsis geninata (Fabricius) and thesouthern fire antS. xyloni Forel, and two imported species are the black imported fire antS. richteri Forel, and the red imported fire antS. invicta Buren.

Description of stages of the red imported fire ant, Solenopsis invicta Buren

Adults. Ant colonies contain winged male and female reproductive ants as well as smaller sterile female worker ants. Size of these castes of ants varies with species. Female reproductive Texas leafcutting ants can have bodies about 20 mm in length. Harvester ant workers range from 5 to 9 mm and reddish brown to yellow or black, while red imported fire ants workers range from 1.5 to 4 mm and reddish brown with a darker abdomen. On the average, worker ants from polygyne colonies are smaller than those from monogyne colonies (Greenberg et al. 1985).

Eggs. The eggs of ants are white to pale yellow and vary in shape with species. Harvester ant eggs are less than 0.5 mm long and elliptical (Brook et al. 1982).

Larvae. Larvae of ant are creamy white, legless and grub-like, with small distinct head capsules that bear chewing mouthparts. Harvester ants are shaped like crook necked squash or a gourd (Brook et al. 1982).

Pupae. Pupae of ants resemble adults in size and shape with appendages appearing distinctly as ridges on the body. They are initially creamy white but darken as the adults develop inside. Pupae of some species, like fire ants, are “naked”, while those of other species, such as harvester ants, occur in capsule-like cocoons.


FAPFS#013, Texas Fire Ant Identification: An Illustrated Key

For more information about ant identification and an illustrated key, see Texas Pest Ant Identification: an Illustrated “Key” (010) or our Information Materials section for slides.


Borror, D. J., C. A. Triplehorn, and N. F. Johnson. 1989. An Introduction to the Study of Insects. Sixth Ed., Saunders College Publishing, New York. 875 pp.

Brook, T. S., C. C. Carter, P. P. Cobb, C. S. Goruch, K. R. Horn, L. T. Lucas, K. Pinkston, D. K. Polet, R. Price, R. L. Robertson, R. A. Scheibner, H. E. Williams. 1982. Insect and other pests associated with turfgrass (J. R. Baker, ed.). AG-268. North Carolina Agric. Ext. Serv., North Carolina State University, Raleigh, North Carolina. 108 pp.

Drees, B. M. and J. A. Jackman. 1998. A Field Guide to Common Texas Insects. Gulf Publishers, Houston, Texas. 359 pp.

Greenberg, L. D., J. C. Fletcher and S. B. Vinson. 1985. Differences in worker size and mound distribution in monogynous and polygynous colonies of the fire ant Solenopsis invicta Buren.J. Kans. Entomol. Soc. 58(1): 9-18.


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