Habitat
Life Cycle and Habits
Life cycles. During the nuptial flight of ants, when winged males and female ants couple and mate. After sperm is transferred to the female, the male soon dies. Females land, locates a suitable nesting sites, looses her wings and begins laying eggs. The first brood of larvae are fed and cared for by the queen, and develop into sterile female worker ants. Thereafter, her sole role is to lay eggs. Worker ants care for the queen and brood (eggs, larvae and pupae), construct and maintain the nest, defend the colony and forage for food.
Colony formation of the red imported fire ant. The winged forms, called reproductives, live in the mound until embarking on a mating (nuptial) flight, which usually occurs in the afternoon soon after a rainy period. Mating flights can occur at any time of the year, but they are most common in spring and fall. Males die soon after mating, while the fertilized queen alights to find a suitable nesting site, sheds her wings, and begins digging a chamber in which to start a new colony. Sometimes, several queens can be found within a single initial nesting site. A newly-mated queen lays a cluster of about a dozen eggs. When they hatch 7 to 10 days later, the larvae are fed by the queen. Later on, a queen supplied with food by worker ants can lay up to 800 eggs per average day. Larvae develop 6 to 10 days and then pupate. Adults emerge in 9 to 15 days. The average colony contains 100,000 to 500,000 workers and up to several hundred winged forms and queens. Queen ants can live 7 years or more, while worker ants generally live about 5 weeks, although they can survive much longer (Drees et al. 1996).
See description of fire ant mounds and sizes under Impact.
Natural Enemies of The Red Imported Fire Ant
(also see Fire Ant Plan Fact Sheets: Potential Biological
Control Agents for the Red Imported Fire Ant (009) and A
Review of "Organic" and Other Alternative Methods for Fire
Ant Control (012).
Microorganisms. Some pathogens are known to attack ants, and several have been marketed for fire ant control, including the microsporidian Thelohania solenopsae, Pseudomonas bacteria and several parasitic fungi, including Beuvaria bassiana, which is currently being evaluated for control (Oi et al. 1994). Parasitic nematodes (Steinernema spp.) seek out and enter insects, paralyzing them and developing in their bodies. Species and strains vary in their effectiveness. Strains tested to date caused ants in treated mounds to temporarily move away from the treated mound, but few colonies were actually eliminated (Drees et al. 1992). However, natural enemies applied to individual fire ants mounds are generally not suitable for area-wide treatment programs (Drees et al. 1996).
Arthropod Predators and Parasites. Some native ant species compete with the red imported fire ant for territory and resources, and are particularly affective predators on newly-mated fire ant queens. The predatory straw-itch mite, Pyemotes tritici (Lagreze-Fossat & Montane), that feeds on and paralyzes developing fire ants is not effective when applied as directed and is potentially hazardous to the user (Thorvilson et al. 1987). There is great hope for success from the introduction of biological control agents such as parasitic phorid fly species (Diptera) currently being evaluated for release in the United States (Morrison et al. 1999, Porter & Alonso 1999). If successfully introduced and established, they are expected to provide only a measure of suppression over large areas, but not eradicate the imported fire ant (Williams & Porter 1996, Drees et al. 1996).
Drees, B.M., R. W. Miller, S. B. Vinson & R. Georgis. 1992. Susceptibility and behavioral response of red imported fire ant (Hymenoptera: Formicidae) to selected entomogenous nematodes (Rhabditida: Steinernematidae & Heterorhabditidae). J. Econ. Entomol. 85(2):365-370.
Drees, B. M., C. L. Barr, S. B. Vinson, R. E. Gold, M. E. Merchant and D. Kostraun. 1996. Managing red imported fire ants in urban areas. B-6043. Texas Agric. Ext. Serv., The Texas A&M Univ. System, College Station, Texas. 18 pp.
Morrison, L. W., E. A. Kawazoe, R. Guerra and L. E. Gilbert. 1999. Phenology and dispersal in Pseudacteon flies (Diptera: Phoridae), parasitoids of Solenopsis fire ants (Hymenoptera: Formicidae). Ann. Entomol. Soc. Amer. 92(2):198-207.
Oi, D. H., R. M. Pereira, J. L. Steimac & L. A. Wood. 1994. Field applications of Beauveria bassiana for the control of the red imported fire ant (Hymenoptra: Formicidae). J. Econ. Entomol. 87(3):623-630.
Porter, S. D. and L. E. Alonso. 1999. Host specificity of fire ant decapitating flies (Diptera: Phoridae) in laboratory oviposition tests. J. Econ. Entomol. 92(1):110-114.
Thorvilson, H. G., S. A. Philips, Jr., A. A. Sorenson & M. R. Trostle. 1987. The straw itch mite, Pyemotes tritici (Acari: Pyemotidae), as a biological control agent or red imported fire ants, Solenopsis invicta (Hymenoptera: Formicidae). The Florida Entomol. 70 (1): 440-444.
Williams, D. F. & S. D. Porter. 1996. Update on USDA-ARS biological control studies on fire ants. pp 143-144. In Proceedings of the 1996 Imported Fire Ant Research Conference. New Orleans, Louisiana.
Additional reading:
Lofgren, C. S., W. A. banks and B. M. Glancey. 1975. Biology and Control of Imported Fire Ants. Annual Review of Entomology 20:1-30.
Vinson, S. B. (ed.). 1986. Economic Impact and Control of Social Insects. Praeger Scientific, New York.
Vinson, S. B. 1997. Invasion of the red imported fire ant. American Entomologist 43(1):23-39.
For more information about ant identification, visit Identification or see the Fact Sheet, Texas Pest Ant Identification: an Illustrated "Key" (010), or Slideshows and Images in the Materials section.
