Ever since tawny crazy ants showed up in Texas in 2002, they have flourished. They did well even in areas dominated by fire ants, the ants which had previously pushed out other ants. No one was able to figure out why tawny crazy ants were able to thrive and spread in fire ant territory. But recently a discovery has been made that explains it.

The researchers, reporting in Scientific American, noticed that after a run-in with a fire ant, a tawny crazy ant grooms itself, spreading a secretion over its body. After numerous tests, it became apparent that these ants were doing something never recorded before—they were taking formic acid from the tip of their abdomens and using it to
detoxify the venom of the fire ant.

When they did this, the tawny crazy ants always survived attacks by fire ants. When these ants were unable to apply the formic acid because their abdomen was blocked (with nail polish), very few crazy ants survived an attack by
fire ants. Tawny crazy ants can become so numerous that ‘snowdrifts of dead ants’ are sometimes seen after a site has been professionally treated.

They nest in any available cavity, and frequently short-circuit electronics. They are also bad for entire ecosystems—they eat voraciously, so some birds and other animals may struggle with less food available.

Tawny crazy ants (also known as Rasberry crazy ants in honor of the pest management professional who first discovered them) are rapidly spreading throughout Texas and the Gulf states. It is still not clear how far they will
end up spreading.