Jan 28 2009
Bible Belt Lizards Evolving
I suspected it was happening. Many a times I’ve stood in my backyard and thought to myself, “I smell evolution.” Is it really the case? According to recent research, it’s happening here in my own lower, somewhat flaccid member-state of the Bible Belt.
What’s happening? Native U.S. Lizards Are Adapting To Escape Attacks By Fire Ants.
In particular -
Penn State Assistant Professor of Biology Tracy Langkilde has shown that native fence lizards in the southeastern United States are adapting to potentially fatal invasive fire-ant attacks by developing behaviors that enable them to escape from the ants, as well as by developing longer hind legs, which can increase the effectiveness of this behavior.
Holy crap. We have fence-lizards in our very yard. I should get a camera and document this alleged EVOLUTION in action. But wait – the lizard legs in my piece of turf don’t look longer, they just look as they are. Hmm. Seems I can’t see evolution. How do I really know it’s happening? Learn me some science? Do I have to?
Okay, I’ll try a little learnin’. Here goes –
Langkilde conducted an experiment in which she compared the responses to fire ant attacks of lizards that were collected from four different sites: one that had not yet been invaded by fire ants and ones that were invaded by fire ants 23, 54, and 68 years ago. Her goal was to determine whether the amount of time since invasion influences the ways in which lizards respond to attacks.
What did Tracy Langkilde find when she wasn’t in the kitchen (where the Bible god would have preferred her to be)?
“The lizards can survive this attack by twitching to flick off the ants and then by running away from the mound,” said Langkilde. “We found that the lizards from sites that have been invaded the longest were more likely than the lizards from sites that have not yet been invaded to perform this survival behavior. Many of the lizards from the uninvaded site and the most recently invaded site just sat there with their eyes closed while the ants attacked,” said Langkilde, who stopped the experiment after 60 seconds to prevent any of the lizards from dying.
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She also discovered that lizard leg length appears to be inherited from an individual’s parents. Langkilde concluded that the lizards living near fire ants are developing behaviors to increase their survival and are evolving longer hind legs in response to attacks by fire ants.
But wait a minute. How the hell do you get from lizards wagging their tails to the conclusion that Darwin was right and my grandpa was a monkey? What? I have more learning to do?
Screw that. I’ve got a cold Bud waiting. Where’s my wife to fetch one?
