Ants are everywhere. In fact, if you took the total mass of all the ants on Earth, it would far exceed the total mass of all the people. But not all ants are created equal. While black ants and carpenter ants are common anywhere and normally inoffensive, there is one kind of ant that is aggressively taking over the South. This is the fire ant.
Fire ants are not native to North America. They originated in South America and were first introduced to the United States on cargo ships in the 1940s. Since then, the fire ant has become a menace. Fire ants are omnivores and will eat anything. Most of their diet consists of plant juices, honeydew from aphids, and flower nectar. However, they are just as likely to prey on other insects, spiders, and even small vertebrates such as frogs, lizards, birds, and mice, which they overpower in groups.
The colonies of fire ants are typical of those of any ant. There are thousands of workers and soldiers, all of them female, and a queen whose only function is to lay eggs. Male ants only exist to mate with queens and start new colonies, after which they die. Fire ant nests are distinctive. They are much larger and more mound-like than the nests of other ants, which makes then nuisances on lawns and anywhere else they can be stepped on. If you do happen to step on a fire ant nest, make sure you are wearing thick shoes, because otherwise you will find out how these insects got their name: they are notorious for their painful stings.
Individually, a single fire ant’s sting is not much worse than that of a bee. Indeed, on the Schmidt Sting Pain Scale (which measures the intensity of insect stings) it only rates a two out of four. But they rarely attack individually. Instead, they swarm over intruders, biting and stinging at any exposed skin. The multitude of stings received in this fashion often add up to be extremely painful.
With their venomous stings and destructive habits, fire ants seem to be unstoppable. Spraying of pesticides has failed to make a dent in their numbers, and likewise the ants have devastated the ecology and agriculture of the Southeast, causing millions of dollars of damage. Furthermore, the pesticides used often cause additional environmental problems. Nowadays, it seems many people are simply willing to let the ants be, as long as they don’t interfere with land development.
Fire ants do have some natural enemies. Black widow spiders, which are themselves infamous for their venom, are specialized ant-killers, and in some regions their diet is as much as 75 percent fire ants. Parasitic wasps also kill their share of fire ants. The wasps lay their eggs on leaves, and the larvae attach to passing ants. When ants enter their nest, the wasp larvae eat the ant larvae. The larvae of Microdon flies, on the other hand, live inside the ants’ nests. They give off an odor identical to an ant larva, so the ants leave them alone, even as they devour the ants’ own larvae.
While it may be impossible to get rid of fire ants entirely, there are plenty of environmentally sustainable ways to remove them from your property. Use granular baits, left close to the nests. Apply the bait directly to the mounds if possible, especially after rain. If you’re nervous about the possibility of even the granular bait contaminating your local wildlife, use boiling water instead; it isn’t quite as reliable but has a proven track record of killing fire ants. Other eco-friendly “pesticides” you can use include pine oil and clove oil, both of which are toxic to fire ants.
It seems unlikely that fire ants will ever be truly controlled. They have established themselves as a constant presence in the United States, and despite many attempts to limit their numbers, they are still as successful as ever. Most optimists, and realists, agree: fire ants are here to stay.