Eastern Fence Lizards are rampant across the American southeast but, in recent years, they’ve begun to coexist with invasive red fire ants from South America. Because the lizards and the ants have similar requirements (terrestrial areas with abundant sunlight), they often find themselves occupying the same space. And the ants don’t like it.
Tracy Langkilde of Penn State University studies the interactions of these territorial animals in Arkansas, Louisiana and Alabama. She’s found that fire ants will attack lizards not just when they’re near the ants’ territory or their mound, but also when they’re simply wandering by. The opportunistic ants will swarm a lizard, roaming its body and stinging it by pulling up the lizard’s spiny scales and stinging the soft skin underneath. Twelve ants can kill a three-inch lizard in under a minute.
So how do the lizards defend themselves against such ambushes?
“Lizards do pretty much what we would do. They shake the ants off using this big body shimmy, and then they run away from the mound. “
Langkilde also found that the longer a population has coexisted with the introduced ants, the more common is this behavior. Further, these lizard populations have longer legs than populations that don’t coexist with fire ants, which may improve their shimmy shake and allow them to live another day.
Langkilde talks about how this adaptation is indicative of rapid evolution in this month’s edition of ESA’s podcast series Field Talk, titled “Lizard Evolution and the Ants In Your Pants Dance.” Listen above or on ESA’s podcast page.