Fire Ants, Stress, and Twitchy Lizards

"For Lizards with Ant Problems, Stress Can Be a Savior"
LiveScience (August 2, 2010)

"Stress may cause harm in the long run, but it can also trigger an immediate survival reaction for lizards when they encounter the painful stings of fire ants.

"That balance between harmful and helpful stress may affect lizard evolution as new threats emerge in their southeastern U.S. environment, according to researchers.

"Fence lizards with higher stress levels behaved by flicking the attacking insects away and running, while lizards with less stress merely froze and took the punishment. The twitchy lizards appear more likely to survive and pass on their stressed-out response, said Tracy Langkilde, assistant professor of biology at Penn State University...."

Fire ants are a new wrinkle in the fence lizards' territory. Back in the 'good old days,' being calm, collected - and not moving - when in a stressful situation like seeing a predator was a good strategy.

Staying still to avoid detection is still a good strategy - provided that the situation at hand isn't an oncoming wave of fire ants.

So, short-term, twitchy lizard live longer when there are fire ants around.

On the other hand, the stress hormones in their systems stunt growth, weaken their immune system, and can interfere with reproduction.

Looks like the fence lizards are in the process of finding a new balance between being so stressed-out that they keel over, or so calm that they're overwhelmed by fire ants.