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Living Sanibel: Fire Ants (Family Formicidae)

By Staff | Oct 20, 2010

Other names: zombie ant, biting ant, RIFA (Red Imported Fire Ant) / Status: FL=thriving / Life span: queens can live for 6 to 7 years / Length: 0.12-0.24 in. (2-6 mm) / Reproduces in upland areas including lawns, fields and woodlands / Found: Urban Areas, Interior Wetlands, Mangrove Zone.

Ants, along with termites, represent one of the most successful species of insects in the world. There are 11,000 known species of ants to date (more are added yearly), 700 species in North America, 207 native species in Florida, 53 exotic species and two species of imported fire ants. The most notorious and familiar is Solenopsis invicta Buren, which is the imported, Brazilian fire ant most southerners are all too familiar with.

The invicta (which means unconquered) fire ant first arrived in Florida, via the port of Mobile, Alabama, between 1933 and 1945. From there it has spread to every state in the South as far north as Virginia and west to California. The sheer scope of its current range makes eradication of this invasive and notorious insect impossible at this point in time.

Fire ants originated in the grasslands of Brazil, where their mounds of dirt helped to keep them out danger during the annual floods of the rainy season. When accidently stepped upon, the worker ants react in defense of their nest, crawling up the legs of the intruder and, through the release of pheromones by the lead ant, the entire colony is signaled to bite at once. The result can not only be excruciatingly painful but sometimes even deadly. For smaller animals, such as alligator hatchlings, baby sea turtles, fledgling birds and small mammals, this en masse bite can cause paralysis and death. Some humans are allergic to the toxins in fire ants and their stings can cause the victim to go into anaphylactic shock, requiring immediate medical attention. Worldwide, dozens of people succumb to fire ant bites annually. In fact, more people are killed annually worldwide by fire ant bites than shark bites.

In the United States alone, more than $5 billion dollars is spent annually on medical treatment, damage and control in invicta infested areas. Fire ants have recently spread to Taiwan, China and Australia where they are wreaking havoc on the natural insect populations and environments.

The bite of a fire ant is incredibly painful. In fact it is not a bite at all but a sting, which originates from the abdomen and injects a toxic alkaloid venom into its victim called solenopsin. It feels as if someone has taken a lit match and held it against your skin; the welts that result from these bites can last for weeks.

Treating the bites properly is essential to avoid infection. To start with, do not squeeze or pick at the pustule as that will greatly increase the chances of infection. Wash the bite with antibacterial soap for two minutes or longer. Disinfect the site using betadine, rubbing alcohol or hydrogen peroxide. If it continues to itch, apply a dab of hydrocortisone cream to the site. Cover with a bandage and repeat the process three times a day until it is healed.

The best way to rid your yard of fire ant mounds is through the use of various chemical applications available at most hardware stores. Pouring boiling hot water on the mound can also sometimes work, but the queen, who can lay up to 1,500 eggs per day, is sometimes hidden below ground as deep as seven feet, so boiling water is not always effective. People have been known to soak the nests in gasoline, then light the ground on fire. Aside from being exceedingly dangerous, this has been proven to be completely ineffective.

Fire ants are eaten by only a handful of birds in the United States and, in reality, have few natural predators in their newfound range. They displace native ants and are very damaging to a host of native flora and fauna.