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Red Imported Fire Ants
"The ants go marching one by one, hurrah, hurrah..." Actually, if this song were about red imported fire ants, the lyrics would say "go stinging one by one". Fire ants sting humans by sinking their mandibles into the skin and swinging their abdomens around to inject venom. The venom serves a purpose. When used against prey, it can kill or paralyze. When injected into humans, the toxic alkaloids produce an immediate burning sensation at the entry site. A swelling soon appears and a blister forms at the site. Within a short amount of time, the blister fills with pus. Venom begins to break down cells and tissues. Reaction to the venom may include nausea and vomiting, disorientation, dizziness, asthma and anaphalaytic shock. Usually the sting just gets itchy and irritated. Less than five percent of people stung experience systemic anaphylactic reaction, which can be fatal. No wonder it sounded like a good idea when Congress initiated a cooperative federal and state program in 1957 to eradicate red imported fire ants from 126 million acres, at a cost of $200 million over a twelve year period. TAXONOMY
Order: Hymenoptera Family: Formicdide Genus: Solenopis Species: Invicta ORIGINOriginally from tropical South America, the red fire ant gained entry to the United States through the port of Mobile, Alabama in the late 1930's on cargo ships. It immediately began to thrive in its new location and colonies spread quickly. The first colony of the ants was found in 1942. Ed Wilson, a 13 year-old boy, came across a mound in the empty lot next to his home. He continued to study the ants while attending college. While he continued his observation, the ants continued to spread throughout the southern United States. By 1975 the red imported fire ant had colonized over 52 million hectares of the United States. The most common species of fire ants is Solenopsis invicta, (S. wagneri) which is also the most aggressive. There are four different classes of red imported fire ants that live in a colony: winged males, winged females, workers, and queens. The North American red imported fire ant is unique in that it forms colonies with multiple queens. WORK, WORK, WORKThe red imported fire ant's life is extremely organized. Every ant has a job to do. They go about doing their job day after day, without stopping. The worker's job is to keep the larvae, pupae, and queen clean. Cleanliness appears to be extremely important to the ants. They are constantly cleaning the larvae, the pupae, the queen, and the colony. The workers also forge to find food for the colony. The red imported fire ant has two stomachs, one for its own food supply, and one for the colony's food supply. The second stomach is called a crop. They feed mostly on other insects but can attack small birds and other invertebrates. Flea larvae, chinch bugs, cockroach eggs, ticks, and other insects are also on their menu. They especially like to eat soft fruits. The winged females go on mating flights and found new colonies. The male's only job is to mate with the queen. Soon after mating, the male will die. The ants migrate from one site to another quite often. A young queen only needs half a dozen ants and one day to build a new colony. Red imported fire ants will build mounds in any type of soil. They also make mounds indoors. In three months a new nest could contain over 300 workers; in a year, with multiple queens at work the nest will contain over 11,000 individuals. At the end of three years, a staggering 50 to 60 thousand ants will have built a multi-chamber mound about three feet high. The ant pictured is a female worker. Her job is to find food for the colony and help clean the colony. TROUBLEMAKERSFire ants can cause quite a problem. Red imported fire ants interrupt farming production because they construct their colonies on precious farmland. They also like to make their mounds in sunny areas. Therefore, pastures are heavily infested. The control of these ants in pastures, hay fields, and recreational turf grass is at least a $28 dollars per acre expense. Livestock and poultry can be injured and even killed by stings. Small birds such as baby quail are fair game to the expanding colony. Farm machinery is often damaged by running over a mound. Red imported fire ants can quickly strip fruit trees of their fruit. They appear to be attracted to electromagnetic fields and attack electrical insulation or wire connections. They are a danger to workers and can cause electrical shorts, fires, and other damage to electrical equipment. One of the most important problems red imported fire ants produce is a heath risk to the human population. In 1987 in South Carolina, 500,000 stings required medical attention, costing $1.8 million. THE MIREX WARAttempts to stop the ever advancing Red Imported Fire ant involved the use of various insecticides. Mirex was developed by Allied Chemical Corporation and used extensively in the war on this insect. By 1967, the National Academy of Sciences had gathered data indicating Mirex was producing substantial negative effects on chickens, fish, baby rats, and especially crabs and other crustaceans. The use of Mirex was subsequently banned. By 1976 when the ban on the use of Mirex had taken effect, the U.S. government had spent over $91.5 million on eradication efforts. There is still a great deal of concern regarding the spread of the red imported fire ant. Competition with native ants has the potential of limiting its range. However, the best barrier may be cold weather. The big question might be, can the red Imported fire ant breed with native ants and acquires a capacity to endure cold weather? To continue tracking the red imported fire ant, we suggested the following links: http://www.uaex.edu/natural/fireant/biology.htm http://www3.sk.sympatico.ca/brucda/980504.htm http://www2.ncsu.edu/unity/lockers/project/pestmngt3/AG268/html/fire_ants.htm http://entweb.clemson.edu/cuentres/eiis/newimp/ni1.pdf
Red Fire Ant Page Created By: Jenny Inman Insecta Inspecta Class of 1999 |
