Crazy ants and fire ants are engaged in a bitter war that is happening on the U.S. gulf coast right now. And for the first time since the insidious South American fire ant came into North America in the 1960’s, it is being defeated by a new invader: the tawny crazy ant. In a paper published Thursday in the journal Science, Edward LeBrun, an entomologist at the University of Texas at Austin, explains how crazy ants are effortlessly winning this battle.
“Other ant species typically avoid fire ants,” says LeBrun, “fire ant venom is so toxic that it’s not something other ants will confront. But these crazy ants will just charge on into the fray with what seems like wild, willful abandon.”
The key to their success, LeBrun says, is the crazy ants’ chemical defenses. When a crazy ant is injected from what would be a fatal dose of fire ant venom, the ant quickly withdraws from battle to apply its own caustic venom onto its body. For reasons researchers still are trying to determine, the crazy ant venom acts like a healing salve, neutralizing the effect of the fire ant’s toxic ammunition.
“And when they’re done, they’ll run right back in to fight and take on another fire ant,” LeBrun says. This tactic is so effective that in the places where both kinds ants live, “the tawny crazy ants are just steamrolling the fire ant populations,” he says.
By putting crazy ants against other ant species, LeBrun and his colleagues found that while the crazy ants will employ the same detoxifying technique against various other ant species, however they are unsure whether it’s effective against any other ant species. From their studies it seems as though crazy ants have evolved to engage and destroy the fire ants.
Crazy ants aren’t a new species, in fact populations of invasive tawny crazy ants have been spreading in the U.S. since 2002, however only in the last few years have scientists noticed a dramatic growth. Fire ants worldwide fear not, it is unlikely the new invader will exterminate fire ants nationwide per David Holway, an entomologist at the University of Southern California, San Diego, who was not involved in the study.