Wednesday, May 16, 2012


Linda, over at Me wrote of her being bitten by fire ants. Fire ants are a migratory species well adapted to survival.

The red imported fire ant entered the United States probably in the 1930s. It was most likely introduced with cargo or in the soil used as ballast in ships from South America that were unloaded in the Mobile area. In the 1940s and early 1950s the red imported fire ant spread to Florida and other southern states in nursery stock and sod. Fire ants currently infest over 260 million acres in Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Puerto Rico 

They have been found to have re-appeared in the Ipswich area of Queensland, Australia after previous imported infestations had been believed to have been eliminated.

Read this account of their 'intelligent migration' from Engineering professor David Hu and graduate student Nathan J. Mlot at Georgia Institute of Technology published in National Geographic:

Fire ant raft
"... Fire Ant Life Raft
Photograph courtesy David Hu and Nathan J. Mlot
When a city floods, humans stack sandbags and raise levees. When a fire ant colony floods, the ants link up to form a literal life raft, such as the one pictured. Now, new research shows exactly how the ants manage this feat.
Engineering professor David Hu and graduate student Nathan J. Mlot at Georgia Institute of Technology had heard reports of ant rafts in the wild that last for weeks. (Watch a fire ant video.)
"They'll gather up all the eggs in the colony and will make their way up through the underground network of tunnels, and when the flood waters rise above the ground, they'll link up together in these massive rafts," Mlot said. Together with Georgia Tech systems-engineering professor Craig Tovey, the scientists collected fire ants and dunked clumps of them in water to see what would happen.
In less than two minutes the ants had linked "hands" to form a floating structure that kept all the insects safe. Even the ants down below can survive this way, thanks to tiny hairs on the ants' bodies that trap a thin layer of air.
"Even when they're on the bottom of the raft, they never technically become submerged," Mlot said.
 The fire ant life raft research is described in the April 25 issue of the Proceedings of the National Academy of Sciences.
—Rachel KaufmanPublished April 25, 2011 ..."


Photograph courtesy David Hu and Nathan J. Mlot

The finished ant raft is quite buoyant, as the researchers found out after attempting to sink a raft with a twig, pictured above. During such "perturbations," the ants contract their muscles, which makes the raft temporarily less buoyant but traps air better, preventing drowning. 

The venom of fire ants is composed of alkaloids such as piperidine (see Solenopsis saevissima). The sting swells into a bump, which can cause much pain and irritation at times, especially when caused by several stings in the same place. The bump often forms into a white pustule, which can become infected if scratched, but if left alone will usually flatten within a few days. The pustules are obtrusive and uncomfortable while active and, if they become infected, can cause scarring. 

Some people are allergic to the venom, and as with many allergies, may experience anaphylaxis, which requires emergency treatment. An antihistamine or topical corticosteroids may help reduce the itching. 

First aid for fire ant bites includes external treatments and oral medicines.
  1. External treatments: a topical steroid cream (hydrocortisone), or one containing aloe vera
  2. Oral medicines: antihistamines
Severe allergic reactions to fire ant stings, including severe chest pain, nausea, severe sweating, loss of breath, serious swelling, and slurred speech, can be fatal if not treated.

 At a home level, one of the best recommended defences is to introduce Venus Flytrap plants (Dionaea muscipula) around suspect areas if the climate is suitable for their growth.

Some reported ‘home remedies’ for fire ant stings :

After washing the bites, as soon as possible:
  • Worcestershire sauce. Cover the bite(s) with a paper towel and saturate with the sauce.
  • Hot water. 
  • Bleach and water (half and half).
  • Cut open a fresh lime and rub the area in several different directions until you feel the burning and itching stops.
  • Ammonia alone, or alternately applying ammonia and hydrogen peroxide with two rags, cotton balls, or paper towels.
  • Soak in a tub of warm water with 3 cups of 20 Mule Team Borax. Borax is a mineral, boron, so you are taking a mineral bath which draws out the venom.
Personally, I'd prefer the aloe vera cream and antihistamines and regularly wash the bite areas in a light saline solution. Cover any pustules that may form with a light cotton dressing


AstridsSoapbox said...

Eeeeewwwww! And I thought our gekko's were bad.

The Elephant's Child said...

I once heard a story (possibly apocryphal)about a young man with a leg in a cast who had fire ants swarm across his leg, biting as they went, including under the cast. I winced in sympathy, being a person who swells to humungous proportions when bitten by almost any insect. And yes, aloe vera sounds the least unpleasant remedy.

Susan Heather said...

Sounds a nasty critter

John Gray said...

well, this entry made me want to live in a plastic bubble for the rest of my life.
I don't DO ants or anything small and leggy!
that's one reason I could not live in more tropical lands.....the insects would send me gaga

JohnD said...

They are not nice, are they and there is a suggestion that they are adapting to more cooler climates.

Then there's also the black fire ant as opposed to the red fire ant!

JohnD said...

Couldn't find anything on Snopes or Urban Legends about fire ant attacks but heaps in the general Google search.

JohnD said...

Yep! sure do!

JohnD said...

Ah! Don't worry JohnG - UK have enough 'critters' all of their own! lol!

Jim said...

Very interesting! We have these ants in Halifax and they are spreading around the province. None on our property as yet but this is a very handy/informative article to keep around, John. Thanks for this!

JohnD said...

You are welcome Jim - Seems my 'cooler climate adaptation' noter is not off the mark,

Eradication is another matter - be guided by your localpest exterminator who knows what works best, Mineral Soda poured on the nest DOESN'T work and has been 'busted' by Snopes!

LindaG said...

Had not heard of black fire ants. Oi. lol. Very interesting post, John. :o)

JohnD said...

Three Types of Imported Fire Ants

The red imported fire ant (RIFA), Solenopsis invicta Buren, the black imported fire ant (BIFA), Solenopsis richteri Forel, and their hybrid (HIFA) all share common characteristics such as a ten-segmented antenna with a two-segmented club, and a two-segmented waist.