Saturday, June 25, 2011

Invasive Species: Red Imported Fire Ant

The red imported fire ant or RIFA: Solenopsis invicta
Welts caused by fire ant "bites"
If you live in the southern United States, I can guarantee you already know of these little insects. They produce prominent, large, sandy mounds and if you step in one or disturb one in any way, they attack (very violently at that), stinging in mass numbers within seconds. Their stings cause a burning sensation and intense itching, which is where their common name comes from. Red, angry welts follow, each marking a different sting, and they will continue to burn for a week or more. For those who are allergic, it is far worse. They are native to South America, and their non-native range spans two continents and includes Australia, the United States, New Zealand, and the Caribbean Puerto Rico and the Virgin Islands. Colonies can be as large as 400,000 ants.

The sting is one of the things that allows them to be such an aggressive invasive. With it, they can bring down much larger prey than other ant species, and also ward off predators. Most horrifyingly of all, if an area floods most ants will have little chance, but the fire ants will build their own raft. Yes, the video is of a raft made out of nothing but ants. Imagine if your home is devastated by a flood and you're wading through the water to safety and come across that.

The red imported fire ant is one of the 100 World's Worst Invasives, listed currently at number 86. This is mainly due to their estimated 500 million to several billion dollar impact on agriculture annually. They damage crops, mess with equipment, and sting workers. They also can infest common equipment, like swimming pool pumps, cars, computers, and washing machines. They are also a major nuisance, as nearly everyone in their non-native range has been stung at least once, and they are dangerous to those allergic to them.

Images are copyright free from Wikimedia Commons 


  1. I have been attacked by these-- standing in a front yard in Eastern North Carolina.

  2. They are vicious little things. When you live in areas that have them you learn what to do to avoid getting stung. I've somehow managed to not run into a mound for some time (six years?), so I fear I'm getting complacent.