A new study has shown that lizards that eat fire ants can protect themselves against stinging bites.

The lizards' immune system might be primed to fight it if they digest and process the ants and their venom. The idea that native species can adapt to protect themselves against invaders suggests that they can coexist instead of being wiped out.

According to Tracy Langkilde of Penn State, lizards with fire ants have different immune profiles than lizards without them.

"Because the immune system is so critical for survival, we wanted to determine if the differences in immune profiles can be attributed to lizards being stung by fire ants or eating fire ants."

Eastern fence lizards are native to the eastern US. Fire ants are native to South America and are considered an Invasive Pest in the US.

Fire ants can be fatal for eastern fence lizards.

The lizards have been in the same area for 70 years, and scientists discovered that the lizards have a different immune profile than the eastern fence lizards. They exposed these lizards to ant venom.

One group of 17 lizards were fed fire ants and the other group of 18 lizards were bitten by fire ants three times a week. The lizards were assessed for their immune response after three weeks.

The assessment included measures of the innate immune system and the adaptive immune system, which develops after exposure to a foreign substance.

We were able to see how different immune resources are used in response to fire ants.

The Fed lizards had higher levels of immune measures than the Stung group. They had an increase in a type of white blood cell called basophils, which is responsible for inflammatory reactions during an immune response, as well as an increase in an IgM that is known to respond to fire ant venom.

The lizard's immune system would be helped by the three heightened responses.

She says that the fire ant-specific antibodies and complement could help bind up venom so it won't hurt the body. It's possible that exposure to fire ant venom can cause an immune response similar to a vaccine. Eating fire ants might help lizards prepare for venom exposure.

The researchers found several similarities in the immune profiles of the Fed lizards and the wild lizards they studied. The higher basophil and fire ant specific IgM counts were similar across both groups, suggesting that these markers are a result of eating fire ants.

There were differences as well. It is possible that some immune measures seen in field lizards are the result of stress caused by fire ants. Something that doesn't have anything to do with fire ants.

Determining how fire ants change the immune profile of lizards gives us an idea of how native species can adapt to changing ecological conditions.

"Consuming toxic/venomous invaders may allow native populations to survive and coexist with them," the researchers wrote in their paper.

The research was published in a journal.