Tawny crazy ants, or Rasberry crazy ants, are a fairly small species of ant. They are typically no more than a tenth of an inch in length. It is reddish-brown in color and covered in small hairs. They are native to South America, particularly regions of Argentina, where they are a serious pest.

One of the reasons they are so problematic is due to a typical ant behavior, the farming of aphids. One of their favorite foods is the honeydew produced by aphids, which has been bad news for grasslands across South America. Sweet foods are preferred, but they will also feed on small insects and will even attack animals such as chickens and livestock. These ants are also problematic because they have no clearly defined nests, preferring areas like underneath rocks. Multiple queens are common within colonies, which also plays a role in the difficulty of control for these ants. Their colonies have also been known to short out electrical circuits.

Tawny crazy ants are a unique species of ant, and it’s not just due to the erratic and unpredictable movements that earned them their name. Like the fire ants with whom they are often in competition with over resources, they have an impressive defense mechanism: these ants bite. The bites are packed with formic acid, which causes a stinging sensation. However, this acid is also used as protection from their competition. Tawny crazy ants use this formic acid as an antidote to help neutralize fire ant venom.

While they are a fairly common pest in South America, they have not yet spread their reach into Wisconsin. In fact, only a few counties in Texas and other Gulf Coast states play host to populations of these ants, as they appear to prefer hot, humid locations near the coast.

Did You Know?
Tawny crazy ants are also known as Rasberry crazy ants, after a Texas exterminator who first identified them in 2002.