"Crazy ants" are taking over the southeastern U.S. by secreting a compound that "neutralizes" fire ant venom.
Fire ants have intensely painful stings; their stings can usually overpower other ant species by injecting them with powerful venom, a University of Texas at Austin news release reported.
When a crazy ant receives this venom it begins an "elaborate detoxification procedure." The crazy ant secretes formic acid from a gland in its abdomen and transfers it to its mouth; it then smears the acid all over its body. This study describes this process for the first time.
In the study, crazy ants that were allowed to use this procedure had a 98 percent survival rate when injected with fire ant venom.
"As this plays out, unless something new and different happens, crazy ants are going to displace fire ants from much of the southeastern U.S. and become the new ecologically dominant invasive ant species," Ed LeBrun, a research associate with the Texas invasive species research program at the Brackenridge Field Laboratory in UT Austin's College of Natural Sciences, said in the news release.
The team found that in regions where fire ants invade the diversity of other insects decreases. This can cause a "ripple effect" on the ecosystem by reducing food sources for birds and other insect-eating animals.
The team observed a "battle" between fire ants and crazy ants over the carcass of a dead cricket.
"The crazy ants charged into the fire ants, spraying venom," LeBrun said. "When the crazy ants were dabbed with fire ant venom, they would go off and do this odd behavior where they would curl up their gaster [an ant's modified abdomen] and touch their mouths."
This observation led the researcher to believe the crazy ants were detoxifying themselves.
In order to test this idea the researchers sealed up the acid-secreting glands of certain crazy ants with nail polish and dropped them in a container with fire ants. About half of these ants died from the stings, as opposed to the 98 percent of specimens with working glands that survived.
Both of these ant species are native to Argentina and southern Brazil. The researchers are still not sure exactly how this detoxifying process works.
