Common Name: Red Imported Fire Ant  
Scientific Name: Solenopsis invicta

Kingdom: Animalia
Phylum: Arthopoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Genus: Solenopsis
Species: S. invicta



Don’t let their size fool you!  Solenopsis invicta, also known as the Red Imported Fire Ant (RIFA), might be tiny, but they are fierce.  Red Imported Fire Ants are an aggressive species of ant found in areas across the globe.  They have many unique characteristics.

Red Imported Fire Ants do not look much different than the ordinary garden ant, but they are much more dangerous.  The minor worker ants are approximately 1/8 inch (3mm) long and the major worker ants are approximately 1/4 inch (6mm) long.  The queens, however, are as big as 1/3 inch (8.47mm) long.  The ants are reddish brown to dark brown in color.  They will usually have a darker abdomen, sometimes black.  You won’t want to get close enough to check their abdomen, though, because their most identifying characteristic is their aggressive nature. If their nest is disturbed, they will swarm out and attack with continual stings leaving  itchy, painful blisters, and sometimes causing severe allergic reactions.  Over 5 million people are stung each year in the United States.  Though deaths are rare, more than 80 people have died from these ants.

Red Imported Fire Ants are originally from South America, but live in areas such as Australia,  Mexico, Asia, and now the United States.  They prefer dry areas with hot climates, although they can survive in below freezing weather.  You would most likely find them in grassy areas.  They have adapted to be able to survive in both droughts and floods.  There are about one-half million worker ants and multiple queens in just one colony!  Typical colonies are 1/3 that size and usually have only one queen.  Since these ants have no natural predators, their population is booming.  Scientist are working to find a way to control their population and their spread.

The Red Imported Fire Ant has no problem competing with other ants for food due to their aggressive nature  Sometimes the fire ants will cause the number of native insects and wildlife to be drastically reduced within 50 to 100 feet of their nest.  The ants can also negatively impact agriculture by destroying seedling crops.  Red Imported Fire Ants are omnivores, therefore they will eat plant and animal material, whether it’s alive or dead.  For example, they will eat turtles, snakes, mice, young trees, fruit, and grass.  Although the worker ants can chew and cut their food with their mandibles, they can only swallow liquids.  When they encounter solid foods, they cut it to carrying size and bring it back to their colony to liquefy it and then share it with the rest of the colony. 

Red Imported Fire Ants have huge colonies and their population continues to grow.  They can be dangerous for both animals and people.  They also make a negative impact on agriculture.  Red Imported Fire Ants are unique insects, but overall they negatively affect our natural environment.  

Author: Amy C.
Published: 03/13

Sources: :,,,,,,,,
The World Book Encyclopedia 2007

Photo Credit:Alex Wild on Feb. 21st, 2009