Red Imported Fire Ants
Order:
Hymenoptera
Family:
Formicidae
Scientific Name: Solenopsis invicta Buren
Distribution
of the red imported fire ant is primarily limited to the tier of states
ranging from central Texas up the East Coast into North Carolina.
They are often introduced into new locales, including northern
states, through potted or balled shrubs and trees imported from infested
areas.
This ant species not only stings humans, but also pets, livestock
and wildlife.
In addition, they can damage crops by feeding on and destroying
seedlings.
Description
Workers
are polymorphic (more than one size) and range from 1/16 inch to ¼ inch
(1.6 mm to 6.0 mm) in length. The
following characteristics distinguish the fire ant from other ant species:
a 10-segmented antenna with a two segmented club, no spines on
the thorax, two nodes on the pedicel, and a prominent stinger.
The red imported fire ant differs from other fire ant species by
having four teeth on the inner surface of the mandible and the absence
of a tooth on the ventral side of the petiole.
Biology and Behavior
Single-queen colonies commonly average 40 to 150 mounds per acre, with 80,000 to 250,000 workers per colony. In contrast, multi-queen (20 to 60 queens) colonies average 200 to 800 mounds per acre, with 100,000 to 500,000 workers per colony. A queen typically produces 2,000 eggs each day. Developmental time for workers averages 20 to 45 days. Mature colonies produce as many as 4,500 swarmers. Mating flights occur six to eight times per year from spring through the fall. Workers live 30 to 180 days depending on size, while queens live six to seven years.
Red imported fire ants typically nest outdoors, however they can infest structures by using exposed soil around plumbing penetrations. They frequently build nests adjacent to foundation walls. Fire ants are attracted to electrical junction boxes and use utility penetrations to gain access to structures.
They
prefer foods with high protein content, but feed on virtually anything
of plant or animal origin. Foraging
occurs up to 100 feet from the nest and continues 24 hours per day if
the food supply is abundant.
Control
The four strategies currently employed to manage this pest species are broadcast baits, individual mound treatment, a combination of the previous methods and barrier-spot treatments. Baits are primarily formulated with abamectin, or one of the various insect growth regulators. Individual mounds are treated using baits, drenches, granules, dusts, aerosols, liquid fumigants, hot water and excavation. While natural and introduced biological controls are continuously sought and used, their effectiveness is limited.
Regardless
of the pest management strategy utilized, most methods require several
repeated applications for control to be effective.
(Courtesy of the National Pest Control Association.)