They thought it was only a three hour tour.

In my career, I have found that the most exciting research is when the results are exactly the opposite of what I had expected. Certainly, it’s nice to show that what you thought was correct, but you really learn something when the opposite occurs–it makes you look at questions in a new way and often leads to new insights. This has happened to me several times, most recently in our experimental study of founder effects in Bahamian anoles (paper downloadable here).

One of the tiny islands on which the founder effect experiment was conducted. Note the scraggly vegetation. Photo by Jason Kolbe.

Here’s the story: we have been conducting studies on anoles in the Bahamas for quite some time, using tiny islands as experimental test tubes. We had seen island populations wiped out by hurricanes, and we had documented anoles colonizing these islands, so we knew that populations often must be founded by overwater dispersal, probably by one or very few individuals. Given the long-running controversy over the evolutionary significance of founder effects, we had long discussed whether we could create an experimental founder effect, in replicate, to see what would happen. But we never started such an experiment, for a simple reason: suitable islands for our various ecological and evolutionary experiments were in short supply, and this experiment wasn’t a high priority.

Enter Hurricanes Frances and Jeanne in short succession in the late summer of 2004.

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On Sunday, the Washington Post published a nice news article covering the recent study on island colonization and adaptation in anoles (pdf now available here). Very quickly, back-and-forth exchanges appeared in the paper’s online comments section, but most of them were debates about evolution vs. creationism/intelligent design, as well as invectives, insults, and ad hominem attacks. The same thing happened when I posted a story on the anole genome and its utility for the study of evolution on a National Geographic news website. Who knew that anole research was so pivotal to the evolution/creationism controversy? Or that it could bring out the worst in so many?

Appended below are the 77 comments that had appeared in the Washington Post by mid-afternoon on Monday.

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Castaway lizards put evolution to the test

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lynnecatlover

12:52 AM EST

Please hope that the little beasts survived and flourished with shorter hind legs, of course !

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akuperma1

2/5/2012 4:48 PM EST

So the key to evolution is a superior being manipulating things. From a lizard’s perspective, what’s the difference between a biologist and a diety?

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httpv://www.youtube.com/watch?v=fAgxpB9fn50

Duke University Press Release. Check out the cool video!

In 2004, Hurricane Francis wiped out all Caribbean lizards found on the keys near the Bahamas.

Seeing an opportunity to study evolution, Duke biologist Manuel Leal and his colleagues took lizards from a larger, nearby island, paired them up and then put the couples on seven of the small keys.

The scientists came back year after year to check on their experiment.

They observed the lizards’ legs getting shorter over time. But, the lizards’ legs did not all shorten to the same size, a hint of the founder effect, where traits from a founding species persist after years of adaptation. It is one of the rare times scientists have seen this phenomenon in nature.

The first results of the experiment were published in a Feb. 2 Science Express article.

You can read more about the study here. And how’s this for a newspaper article title: “Lowly lizards settle ‘founder effect’ theory“?

Citation: “Founder Effects Persist Despite Adaptive Differentiation: A Field Experiment with Lizards.” J.J. Kolbe, J.B. Losos, M. Leal, T.W. Schoener and D.A. Spiller. Science Express. Feb. 2012.

Many arboreal animals get from one place to another by jumping. But there’s a problem: branches, particularly narrow ones, aren’t stiff. As a result, as the animal starts to jump by pushing against the branch, the branch gives way and bends. As a result, some of the force that could be used to push off is dissipated in pushing the branch away. One potential solution would be to avoid bend-y branches; another would to make like an Olympic high diver and wait for the branch to spring back, and then use the recoil to help launch the animal forward. Do animals use any of these tricks? Or is their jumping compromised on pliable surfaces?

Turns out that there hasn’t been much work on this, but the research that has been conducted, on birds and primates, has showed that jumping performance is, indeed, reduced on flexible surfaces and that there is no evidence for animals powering off a branch’s recoil. No work has been conducted on small animals, so Casey Gilman set out to remedy this shortcoming by examining the jump biology of the Florida green anole. You can read here about the background to her study and see some photos of the study site.

The main findings of the study can be summarized easily: 1. In the wild, green anoles frequently use very compliant (bend-y) surfaces such as narrow branches and leaves; 2. In the lab, when anoles jump, they do not use the recoil of the support to increase their jump distance; and 3. The more flexible the support, the great the reduction in jump distance.

The most exciting finding of the study, however, was something completely unexpected. The reason that lizard jumps were short from very flexible supports was not just that the support’s give wasted some of the lizard’s push. Rather, what happened was that as the support recoiled, it smacked into the underside of the tail of the launching lizard. This in turn pushes the back end of the lizard up and the front end down, and instead of sailing through the air with the greatest of ease, the lizard does an ungainly face plant, as the video above illustrates. Apparently, this happened frequently when lizards jump off of very pliant surfaces.

Who knew? It certainly makes sense, but I have to say, I’ve never seen a lizard gobsmacked by a branch as it jumps. Maybe it happens too fast to actually recognize what’s happened, but I don’t recall seeing lizards jump in such a klutzy manner. Has anyone noticed something like this in the wild?

More generally, an obvious next step is to not only measure the pliancy of the perches on which lizards can be found, but to observe their movements and see if they choose to jump from particularly stiff surfaces, relative to the ones they use more generally. Word on the street is that Gilman has already conducted just such a study, with fascinating results. Stay tuned!