RIFA and Other Fire Ants
Red Imported Fire Ants -- What You Need to Know
I have been stung by fire ants more times than I can count, so I have no affection for these aggressive insects. They are spreading throughout the southern US, and if there enough nests they can make just going outside nearly impossible. They can kill small animals by attacking by the thousands, and the presence of fire ants can drive down property values and even force homeowners to move. As a pest, fire ants are constantly expanding their territory northward. The situation may be intensified by climate change.
RIFA -- The Red Imported Fire Ant
Ants, wasps and bees are related, and belong to the order Hymenoptera. There are several species of fire ants, and all fire ants are in the genus Solenopsis. There are actually more than two-hundred species of fire ants, but the main pest species is Solenopsis invicta, the Red Imported Fire Ant, also known as RIFA. RIFA was imported by accident from South America in the 1930's by a cargo ship that docked at Mobile, Alabama. The ants came ashore and have been spreading throughout the South ever since. And it's not just in the US that these ants are a pest -- the red imported fire ant is also a serious invasive species in Australia, the Philippines, Taiwan, and China.
Control of the Fire Ant
Control of fire ants is a matter of containment and co-existence, because there are so many in such a wide area that eradication is essentially impossible. If you are one of the estimated 40 million people who live in a part of the US threatened by RIFA, there are things that can be done to minimize the impact of the fire ant invasion.
Areas of the US Affected by RIFA - The spread of the red imported fire ant
It's easy to see that the red imported fire ant has made its home in the southern areas of the United States. The reason isn't difficult to guess -- the cold winters beyond a certain point freeze and kill the insects, limiting their geographic spread. So when we look at a map of the spread of RIFA, what we are really seeing is a weather map.
Climate change may affect this picture, though. If temperatures rise to the point of moving the line of "cold" winters farther north, RIFA (and plenty of other species) can be expected to follow. Outcomes like this are a side effect of global warming that is often overlooked. But this may ultimately be one of the most profound consequences of warmer climate: for example consider the mosquito that spreads malaria. It, like RIFA, can't survive cold winters, but if it gets warm enough they'll breed and spread the disease.
Fire Ants Communicating
Like virtually all ants, red fire ants are social insects. This means they live in colonies, but it also means that they have evolved division of labor. Not only do different groups within the nest perform different duties, but they have different body shapes and features that enable them to do their specific tasks. For example, a soldier ant tasked with guarding the nest and columns of workers moving in and out will typically have much larger mandibles and a fiercer disposition than a worker. The queen is built to produce and lay thousands of eggs, while males are small insects whose only role is to fertilize the queens.
Social insects display nearly human qualities. Division of labor, caring for their young, and community living aren't qualities you usually attribute to bugs, but ants, bees, and some other insects have been doing it for million of years longer than we have.
Amazing Fire Ant Video - The Awesome Power of RIFA
From the destruction of a dragonfly to the power of teamwork, fire ants show what they can do in this spectacular video from National Geographic.
Fire Ants -- How They Bite
Fire ants use a stinging technique similar to many ant species, only with a twist. Like many ants, fire ants begin by seizing their victim's skin in their sharp mandibles (pincers). That hurts; but then the fire and uses that grip to deliver a series of stings in a circular pattern. Fire ant stings have a burning quality -- hence the common name -- and result in a raised bump than can itch and burn for up to a week after the attack. If there are enough stings, the victim can go into anaphylactic shock, a life-threatening emergency.
Fire Ants Mate 200 Feet in the Air - Not exactly the mile-high club, but pretty good for an ant...
Winged fire ant queens are another example of the diversity these social insects possess. Periodically, both queens and males take to the air, where they mate high above the ground. When they return, the queens lose their wings and begin laying eggs. Each queen is capable of producing millions of eggs, which develop and hatch into millions of workers and fighters. It's no wonder that efforts to stay ahead of the spread of RIFA have so far failed to stop their advance.
Solenopsis Species in Leaf Nest
Some species of fire ants (genus Solenopsis) construct nests in large leaves. In the picture, you can see the insects in a leaf nest that's been opened up. The little white things are grubs and larvae, which the adults will protect by moving them from the scene of destruction of their nest. The adults will carefully pick up the fragile immature forms in their mandibles and carry them to safety.
Of the 200-plus species of Solenopsis collectively referred to as "fire ants," only one, the red imported fire ant, has become a pest. As a group, Solenopsis ants are spectacularly successful and fascinating to study.
Do You Live With Fire Ants?
Butterflies and Ants -- A Love Story
It sounds like something out of science fiction movie, but there are butterfly species that have a complex relationship with ants, including special organs on caterpillars that provide ants with nutrition. One group of metalmark butterflies in the tropics have gone way beyond that. These butterflies in the genus Aricoris are being studied by scientists trying to describe the complex interactions between these insects.
Among the things they believe are going on includes caterpillars living in fire ant nests and being fed regurgitated food by the ants; they also may feed directly on the ant larvae and pupae. These caterpillars also have special structure on their bodies that help them communicate with ants, and also may be able to release a chemical that is nearly identical to the fire ants' alarm pheromone.
What this all adds up to is a beautifully complex network of interactions that illustrates the almost unbelievable relationships between species going on all around us all the time.
A Fire Ant's Worst Nightmare - an "Alien" Movie in Real Life
Nearly all insects are susceptible to attacks from parasites. Parasites are insects that lay eggs on the body of other insects, the "host." The young hatch out and feed on the internal organs and fat stores of the living host insect. The host lives with the parasite inside, until at some moment when the parasite exits and flies away. Then the host is either dead or well on the way.
The parasite that often victimizes the Solenopsis genus is a small fly. It lays one egg on an ant and flies away. Soon the grub-like larva hatches from the egg and develops inside the body of the ant. Later in its development, the grub moves to the head capsule, or "skull" of the ant, and releases a chemical that dissolves the muscles of the ant. This kills the ant, but more specifically causes the ant's head to fall off. The head capsule makes a hand-dandy "cocoon" for the developing pupa, protecting it from predators until the adult fly can chew its way out of the skull and fly away.
And this is just one of many unbelievable "Parasite stories!"
Parasite Flies Emerge from Ant Skulls...
Fire Ants BITE - Or, More Accurately, STING
This photo of a poor guy who got attacked by dozens of fire ants shows the nasty effects of the insect's bite. The scientific name for the ant family is "Formicidae," which refers to the fact that ants tend to protect themselves with formic acid, a strong corrosive that can burn and blister skin.
In the case of RIFA, however, the venom is alkaloid-based. The sting, delivered from the ant's rear end (like bees and wasps -- which are closely related to ants), begins with pain and itching and then turns into a nasty, painful bump. These bumps are susceptible to breaking open when scratched, which can result in infections. Infections, in turn, can result in permanent scarring.
Some people are allergic or sensitive to fire ant stings. If that's you, and you life in a RIFA-infested area, it's smart to have a plan for a possible allergic reaction to fire ant stings.