Imported fire ants are an important pest in the United States with an estimated cost well over one billion dollars per year. This pest is widespread in the south and southwest, and has a major impact in urban, agricultural, wildlife, recreational, and industrial area's. The geographic range of the imported fire ant continues to expand and will probably continue to increase without the implementation of a centralized pro-active management program.
Imported fire ants in the southern United States are comprised of two species, the black and red imported fire ant, Solenopsis richteri and Solenopsis invicta, respectively. Both of these species, as well as an interspecific hybrid of the black and red imported fire ant are found in Mississippi.
Imported fire ant colonies are comprised of adult ants and the brood, which includes eggs, larvae, and pupae. The adult ants within a colony consist of several castes (forms), including one or more queens, winged reproductive forms (both male and female), and sterile female workers which are divided into a major or minor worker caste based on size. The queen lays eggs that will go through four larval instars before pupation occurs fifteen days after egg laying. Adult ants will begin to appear 23 days after egg laying. The average life span of an adult worker will be sixty to one hundred and fifty days, while the queen ant can live up to ten years.
The imported fire ant has a seasonal life cycle that starts in early March with the beginning of egg laying by the queen and continues until the following November, when most of the brood will disappear. The winged reproductive forms of the imported fire ant are most abundant in the early spring, and slowly decrease throughout the summer. Typically, the winged reproductive forms will leave the mound after a rain on a mating flight. The males will die soon after mating while the fertilized females or queens will find a suitable site for a colony. The queen will lose her wings, burrow into the ground and then start the new colony. A newly mated queen will usually form a mature colony after three years.