After a very long and tortuous path, our paper on CTmin finally came out today in The American Naturalist. If you are interested in reading it, here is a pdf. This is one of those studies that requires an in-house description to fully appreciate its content, particularly because two of my friends were critical players in the story of this project’s development. As they did their best to convince me that it was not such of a great idea to expend energy on this study.
|Ray Huey and Manuel Leal at the Anolis Symposium|
A long time ago, I told Alex that we should measure CTmin (the lowest temperature at which lizards can maintain coordination) for the introduced population of A. cristatellus in Miami. His response was along the lines: "Ray has shown that the physiology of lizards is relatively rigid, so why should we waste our time?" I tried to convince him that Miami is cold for a Puerto Rican. Being from Minnesota, he was not convinced. I then mentioned that anoles sleep on top of vegetation, usually leaves, which probably limits their ability to escape cold weather. But, that was not good enough for him either. This should not be surprising because he seems to be predisposed to reject my ideas. Finally, I approached Ray, and asked him the same question. His answer was similar to Alex's: “Physiology is very rigid. Why are you going to waste your time?”
Although, both of my attempts to get my friends on board with this project failed to produce a positive response, I decided to go ahead and prove them wrong, in part, because one of an advisor’s jobs is to keep the students (Alex) humble. So, after a few more discussions, Alex agreed that I would bring A. cristatellus from Miami (he was not going to waste his time) and that we would measure CTmin to compare to his data from Puerto Rico. In March of 2010, I went to Miami to collect a series of individuals of A. cristatellus. Nearly two weeks after collection, Alex and I got together to measure CTmin. Because Alex was still so skeptical, we decided to make a friendly wager, which is commonly in the form of a free lunch or dinner in our lab. If lizards from Miami had a lower CTmin than lizards from Puerto Rico, Alex would treat me to a nice lunch; however, if Alex was correct, I would be treating him to several lunches (needless to say, I felt that this was money in the bank). After measuring a few lizards, it was clear, the individuals from Miami were active at temperatures at which individuals from Puerto Rico were like popsicles. Below is the original graph, which got me a free lunch and which was of the first version of this paper when it was submitted to review.
In a nutshell, we found differences in CTmin between populations. After collecting data on CTmin during the fall, we submitted the MS. However, although both reviewers found the manuscript promising (see below), they asked for additional data, including CTmax for both populations.
" To summarize, this is a promising study that suggests that (i) cold tolerance has diverged genetically between populations of lizards in merely 30 generations, and (ii) that thermal changes can result in rapid evolutionary responses in tropical species. If the authors could provide the additional data required to solidify these suggestions, a revised manuscript could make an important contribution."
We moved forward and collected the additional data, some of which is shown below in a new figure.
|Figure 2 from paper, showing differences in CTmin, note the values are the same as those of the original figure.|
In the end, this has turned out to be an interesting story. It is one of those cases in which the results are what you should expect when you "think like a lizard". On one hand, Ray is correct -- physiology seems to be relatively rigid because behavior buffers the lizards from selection. But for a sleeping anole, over a leaf in a winter night, behavior is not such a useful buffer. Thus, we might have found the Achilles heel of behavior. It has also provided the opportunity for Alex to reflect on his initial viewpoint, and to learn that maybe once in a while it is ok to listen to your advisor. So it turns out that "el que ríe ultimo, ríe mejor"