Friday, May 30, 2014

How Crazy Ants Spread

Alexanderwild.com
A few years ago we lost our phone connection at Bull Creek.  The phone company came out and opened a connection box on the pole and it was totally stuffed full of ants and their eggs and larvae.  One quick spray of Raid and our problems were over.  These were just our native ants, a mere taste of what the latest invasive species of ants may bring.

The Rasberry crazy ant (a.k.a. tawny crazy ant or Nylanderia fulva)
was named for the Texas exterminator who noticed their increasing numbers in 2002.  They get the crazy title from their wild and crazy gait as they travel, avoiding the orderly lines common to other ants.  They arrived in Texas and the Florida coast from Brazil and fell in love with our country.  They can nest anywhere and eat almost anything, the perfect ingredients for an invasive species.

They have a particular affection for electrical circuit boxes, possibly drawn to them by the warmth of resistance or the magnetic fields the currents produce.  Either way, they can cause short circuits by chewing insulation or packing tightly together as happened with another species in our phone box.  Worse yet, if an ant happens to be electrocuted, it will release an alarm pheromone which will bring its cohorts running to defend it, sometimes causing a short circuit.

Red imported fire ants-  Wikimedia
Red imported fire ants (RIFA) have already received lots of press as they have invaded the south.  They have reached 25 states as well as Asia and Australia, transported by their new best friends, humans.  Their reputation comes from the painful stings they deliver when disturbed by humans.  Unlike most ants which bite and then spray the bite wound with formic acid, RIFA have a sting with a necrotizing toxic alkaloid.  They rapidly displaced many native ants.

RIFA have an unusual strategy to survive in their native environments in the wetlands of Brazil where they endure frequent floods.  They simply build rafts and float to a new area.  They are even able to build bridges across small flooded areas.  Once the raft bumps into a structure such as a tree, they grab on and climb to safety until they can start a new colony. 

The process is explained in this Smithsonian Magazine article.  Basically, their hydrophobic bodies, which repel water, leave air spaces between their bodies even when tightly compacted masses of ants are forced under water, serving as a group life preserver.  By this tactic, a mat of ants can float along the flood awaiting a new place to land and start all over.  With climate change creating increased flooding and rising sea levels, there may be a message for some of our human colonies.

These fire ants tend to build large mounds which can be destructive but don't usually involve human dwellings.  They tend to keep to themselves unless we disturb them.  They have now met their match with the crazy ant.  The crazies produce chemicals from where a stinger would be, then use their legs and mouth to spread it on their bodies like a lotion.  This is an antidote to the fire ants chemicals.  It also sprays this acidic mix as a defense, allowing them to take over new territories from other ants.


How bad are crazy ants?  In some places they had been introduced to control fire ants.  In Texas where the red fire ants had taken over and are now being driven out, people want the fire ants back!  You can find out why and see the crazy ants in action in this video.

No comments:

Post a Comment