The crazy ant, the latest ant to invade North America, is having remarkable success at replacing its predecessor, the red fire ant, former king of the invaders. Part of the reason, according to research at the University of Texas, is that the newcomer can detoxify fire ant venom in a way not seen before in other insects or animals.

The crazy ant uses its own venom to neutralize that of the fire ant, which is deadly to many other ants and gives the fire ant its notorious sting.

Crazy ants, Nylanderia fulva, are named for their scattershot movements and were first seen in the Houston area and in Florida 12 years ago. They have since been found in Mississippi and Louisiana. They can quickly dominate an ecosystem, wiping out the fire ants that came before them, according to Edward G. LeBrun, who reported the new research Thursday in the journal Science.

Dr. LeBrun and his colleagues Nathan T. Jones and Lawrence E. Gilbert exposed crazy ants to fire ant venom and recorded video of the behavior that followed.The crazy ants engaged in an intense kind of grooming, in which they repeatedly seemed to take their own venom from a pore in their abdomens and spread it all over themselves.