Adventures Down South concludes - lizard catching, veg surveys, lab work, and the wrap up

One extremely valuable lesson I've learned while attempting to document my scientific endeavors/adventures is... post when you can. There were times at the end of my journey when I had a free hour or two and thought, "Oh, I'll just rest now. I'll post it tomorrow. I'm sure I'll get another free moment." Nope. If it happened, and you have the video (I did), post it. Post it now. Now I know. 

I am no longer chasing lizards, but am back home, busy analyzing the data I collected in Florida. And, I have finally gotten a free second to wrap up the field blog.

Sorry for the delay, folks! It is still summer, and the lizards are still hopping around (though not anywhere near me). I hope you haven't lost interest in them!


Last time I posted, I had abandoned Miami (due to crappy weather) to head back to my original field site to conduct vegetation surveys and catch lizards. Lucky for you, I documented all this fun on video!

First I present: vegetation sampling! Remember that in this study I am interested in how the habitat structure affects male density in the population, how male density affects the way these males compete for mating opportunities, and how differences in habitat structure, male density, and male-male competition affect postcopulatory sexually selected traits. So, it's really important that I record and analyze vegetation structure in the areas where I capture the lizards (and where I record their densities). This video shows how I systematically measured the vegetation at points along a transect (see terms or phrases) with the help of my most excellent field assistant wife, Toni.

If it wasn't totally clear in the video (and it probably wasn't), here are what the transect and sampling points look like if you were a giant looking down at them.

If it wasn't totally clear in the video (and it probably wasn't), here are what the transect and sampling points look like if you were a giant looking down at them.

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In case you're wondering, field gear varies from person to person, project to project. Toni is armed with a walkie-talkie, the GPS unit, and a backpack equipped with a water bladder and extra lizard bags, but she is sans sleeves, doesn't seem to require a hat, and is wearing shorts. I, on the other hand... well, in addition to my binoculars, lizard noose, and field notebook (and backpack, bags, and walkie-talkie), let's just say I am not a fan of sun or mosquitos, so I prefer to sweat rather than wake up red and swollen. Our good friend Clark calls this my winter wear. I call it sensible.

And, if you haven't seen a 50 meter tape before, now you have. Tell your friends! This is standard ecological equipment. I got this one on the free table in the Biology Department at UNM. Not surprisingly, it's actually a 49 meter tape. It requires a bit of extra fussing when I do 50 meter transects, but what the heck, it was free! 

 

 

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Now the moment you've all been waiting for: Catching lizards!


I caught 15 males and 15 females in this population. Once I caught them I took them back to the lab to measure their body mass and length, collect ejaculate from the males, and prepare the lizards as specimens so I could study their genitalia back in the lab at UMass.

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Here you can see my makeshift field lab, a green anole male that I am taking body measurements of and collecting ejaculate from (the awkward-looking image of a lizard with a pipette tip in his cloaca) . I was planning on making a small video of this procedure, but time was of the essence at this point (it was a crazy field season), and my collaborator Ariel Kahrl has a fantastic video already online. She is the expert in this field (and be sure to check out her field blog - it's been updated with her latest adventures in the tropics)!


Adventures Down South wrap-up: what does a doctoral candidate do when the field season doesn't go as planned? Have a back-up plan!

So... remember that my original plan for this study was to find several populations with different habitat structures so that I could compare them to see how the environment affects male-male competition and postcopulatory sexually selected traits? Such a great plan! Totally do-able when things like unnaturally cold winters, invasive species, and untimely inclement weather aren't in the picture. But with field studies (because they're in the field, and subject to nature in all its glory), you never really know how much you'll be able to accomplish, or if you'll even be able to get any data at all. So, though this was the most challenging field season I've had in YEARS, I feel fortunate to have any data at all. And, the data is good.

What is my back-up plan? I'm glad you asked! I knew going into this field season that I might not find multiple populations that would work for this study (why? because they all need to have at least a hundred individuals, and they all need to have different habitat structures so I'd be able to compare them - again, totally do-able, but the more components required for the study to work, the greater the chances are that things won't go as planned). The interesting thing about postcopulatory traits in lizards is that we know very little about them. I was able to collect habitat data from three different areas in one population (three 50-meter transects), and collect males and females from these three areas. With these data I can show how variable postcopulatory traits are within a population. This is really important, as evolution occurs at the population level, and sexual selection and evolution require variability.

Is there variability in testis size across males in a population? Are males under differential sperm competition (postcopulatory male-male competition) within a population? How variable is hemipenis shape and size across this population? How variable is the female genitalia? With my data I can answer these kinds of questions. Because I was able to catch animals from the north, east, and southern parts of the population, I can also look at how these traits change from one end of the population to the other (if they do at all). I can also compare these traits in my study population to museum specimens from around the country, to compare populational variability to continental variability.

No, my field season did not go as planned. But I did get enough data to make a dissertation chapter out of it (with a little help from some museum specimens), so I'll be OK. This sort of outcome, though somewhat disappointing, was not entirely unexpected. But it was an adventure!