Anole Performance Meta-analysis!

http://onlinelibrary.wiley.com/doi/10.1002/ece3.528/full

Example of a three-task Pareto front in a 3D morphospace, Figure 9 in Sheftel et al 2013.

 

I want all of your old performance data.

Who am I? I am a Ph.D. student and the thrust of my dissertation project is to arrive at a better understanding of how selection, trade-offs and constraints act on suites of performance traits, leading to adaptive phenotypic shifts in populations and, ultimately, evolutionary change. I am particularly interested in constraints imposed on performance evolution by intralocus sexual conflict, and in the relationship between preferred and maximal performance.

What am I going to do with it? I am conducting a meta-analysis of existing performance data, which involves mapping suites of performance traits onto lizard morphospace and fitting a multivariate response surface. This surface can then be used (by everyone!) to predict trade-offs between different types of performance traits in various selective contexts, and to identify regions of morphospace associated with performance peaks and valleys. These areas, and the taxa that occupy them, would thus be of interest in terms of looking for behavioral compensation or other solutions. Conversely, areas of morphospace devoid of extant taxa may be indicative of insurmountable constraints or something even more interesting. Such insights will, I hope, inform more exploratory, experimental and comparative avenues of investigations.

I’m focusing on Anolis in particular to start with, and I’d like to quantify the relationships between the span of extant anole morphology and any and all whole-organism performance traits. But to do this, I need data! Lots and lots of data! And I don’t have enough 🙁 Which means I need your data.

What I need:

 Raw data1 from previously published studies involving performance trait data along with morphological2 measurements for any and all Anolis species would be very useful and much appreciated. The more coverage of morphospace/performance space, the more useful and powerful the model!

If you’ve ever measured any of the following performance traits in anoles, you’ll probably be getting a grovelling email from me, but just in case you have somehow escaped my scrutiny, or don’t want to wait for the grovelling email, here is what I am looking at:

  • bite force
  • sprint speed
  • acceleration
  • endurance
  • exertion
  • maneuverability
  • jumping
  • climbing
  • clinging

Performance data for multiple traits measured in the same individual will be the most informative, but I will also need plenty of data on single performance traits. I have few other standards (as far as this project goes), so anything will be useful!

Thanks so much for reading this far! I sincerely hope this piques your interest and inspires you to share your work with me. I will of course be open to discuss any and all aspects of data-sharing, collaboration and subsequent use or availability of the data. All contributing authors will be acknowledged and papers cited, or whatever else is necessary! If you have anything you would like to contribute please feel free to contact me directly @ acespede@uno.edu.

1 I can use raw data files, in whatever format (e.g., .xls, .txt., .sys, .jpg of a lab notebook or rum-stained bar napkin).

2 I would be happy with anything from SVL-only to comprehensive measurements for individual limb components, toe pad area, etc. Body size and limb measurements are ideal!

(Figure from Sheftel, H., Shoval, O., Mayo, A., Alon, U. 2013. The Geometry of the Pareto front in biological phenotype space. Ecology and Evolution, 3(6): 1471-1483)

X-Ray Oddities in the Bahamas

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We’re back in the Bahamas for our yearly trip monitoring evolution of brown anoles on small islands (most recently reported on a year ago).  These populations were hammered by Hurricanes Irene and Sandy in 2011 and 2012, and are just now recovering. Most exciting to us was one population reduced to two individuals, which seemed to disappear during the course of our visit last year. Had the population gone extinct? No–we’ve found 14 lizards there this far. Hooray.

Part of what we do is capture lizards, bring them back to the field lab, and x-ray them to measure their morphology, to see how morphology changes from one year to the next. And while doing so, we see all kinds of interesting anomalies. For example, check out the left hind leg of this female–she’s missing most of the toes on that foot. Turns out that that lizards lacking the full complement of digits is not very unusual (check out this post from several years ago on more severe mutilations).

But this year we’ve had some more unusual sightings. Check out the left knee of the male below. Clearly, he broke his femur and it grew back oddly. Yet, it works–this guy was fat and sassy. It would seem amazing that a lizard could break its femur and survive, but here’s the proof.healed broken leg

And check out the tail on this guy. Looks wacky, right?

beat up lizard

The x-ray, however, doesn’t do it justice. It’s not only wickedly bent to the side, but also upwards!

Photo by Manuel Leal

Photo by Manuel Leal

Who knows what we’ll find tomorrow?

Proud of My “Browns”

Me in uniform – many years, kilograms and grey hair ago.

Me in uniform – many years, kilograms and grey hair ago.

For many years, most units in the South African Defense Force used a plain medium brown uniform, called nutria. Soldiers commonly referred to it as “browns.” A few years before my national service, the defense force started phasing it out, replacing it with the “Soldier 2000” camouflage design. When I was conscripted to serve in the South African Medical Services (SAMS) in 1993, SAMS was the only unit that completely still used the nutria uniforms, and although not as “modern-looking” as the other uniforms, we developed a sense of pride in our “browns.”

I believe the brown anole (Anolis sagrei) needs little introduction to Anole Annals readers. I am very fortunate to have been able to do my research on the invasive population of these lizards in southwestern Taiwan. I have been a naturalist at heart since a very young age, but these lizards were my introduction to the academic side of natural history, and because of my work on them I have made numerous friends and acquaintances. So, naturally they hold a special place in my heart and mind.

A female brown anole (Anolis sagrei) from my study area in Santzepu, Sheishan District, Chiayi County, southwestern Taiwan.

A female brown anole (Anolis sagrei) from my study area in Santzepu, Sheishan District, Chiayi County, southwestern Taiwan.

Unfortunately these feelings brought a sense of guilt within me. I know all too well that they are an invasive species, which has certain impacts on native species. And yet, it is hard not to marvel at them and their ability to overcome the numerous obstacles they face in this foreign habitat.

The other day, while reading the obituary of Henry S. Fitch (1909-2009) in the 2009 issue of Herpetological Review (40[4]: 393-400), the words of Raymond B. Huey suddenly made it all so clear to me. He described an instance in which he left a meeting at which Henry Fitch was a speaker, with a haunting lesson, “We should do science because we love the process, not because we need to love the results.” I believe that for us who work with invasive species, this is also a message. So now, when I see brown anoles, I no longer have to feel guilty when I do not wish they were rather tree lizards (Japalura spp.) or grass lizards (Takydromus spp.). I admire the “browns” and I find the process of learning about their natural history truly fascinating – I love it! I wonder how many other researchers working on invasive anoles share this sentiment?

Club LizKids – Sign Up Again!

Club LizKids appears to be the new healthcare.gov…

Many of you visited my lab’s website for kids – lizardsandfriends.org – in the past few days, and a good number of you signed up your children to be a member of our Club LizKids email list.  Thanks so much for your interest!  We hope you and your kids will find this to be a fun group.

BUT, in my recent communication with some of you, I’ve learned that only some of the Club LizKids notifications were coming through to me, even though you received a message confirming your submission.  My web developer (the amazing Tara Whittle) jumped right on that, and we’ve now fixed the problem.  So, if you tried to register for LizKids earlier, please do so again!  

New Green Anole from Colombia

Anolis limon

dewlaps

Anolis limon on top, and the closely related A. chocorum (middle) and A. ibanezi (bottom).

The parade of new anoles continues, and this one is beautiful! Velasco and Hurtado- Gómez, in a new paper in Zootaxa, describe a new species of green anole from northwestern Colombia, Anolis limon. The species is closely related to other green lovelies, but differs in dewlap color and a few other characteristics.

As we have chronicled in these pages, the number of anole species continues to rise, up to 388 according to these authors. More importantly, Colombia—lucky place—is the global leader in anoles, with 75 species.

Here’s the etymology of the name: “The specific name limon makes reference to the resemblance of the body color of the females to the green color of the fruits of the lemon tree (Citrus x lemon).”

And the figure below reveals the distribution of the new species and others.

map

New Lizard-y Website for Kids

If there are any children in your life that are interested in lizards (and what kids aren’t?!), you may want to check out a website my lab is developing: lizardsandfriends.org.  This website is one of our outreach efforts to help make connections between schoolchildren (particularly around the fifth-grade age/reading level) and scientists.

LizFriendsCrop

We’re working to meet several goals with this website:

1.  To show children how science is done.  Too often, children (and adults) have misconceptions about the process of science.  So, our website aims to show that scientists work together in teams; that scientists use math, communication, and problem-solving skills; that scientists are a diverse group of people; and that science can be a lot of fun.

2. To make science accessible to students.  By writing about our ongoing research projects at the fifth-grade reading level, we hope to engage young children with the idea that they, too, can be scientists. The website also offers several options for website-users to engage with the scientists in my lab, including Club LizKids, an email listserve that connects with kids via more personal updates from the lab.

3. To provide resources for teachers to use lizards in their own classrooms.  Because science is tested for the first time in Texas in the fifth grade, in some cases science is not taught until the fifth grade.  We are working with local (San Antonio) fifth grade teachers to develop resources that help them to teach the Texas science standards using creative, engaging approaches – although the resources on the website are available to all!

We’d welcome your feedback on the site.  We aren’t drawing a lot of “comments” on the blog posts yet, but we do get a lot of hits, so people are finding us.  Hope you enjoy it!

Indian Robin chasing a Sitana

I’ve been re-watching some of my Sitana videos from 2012, and was reminded of an odd interaction between an Indian robin and a male fan-throated lizard (Sitana ponticeriana), from a population in Kutch, Gujarat, in western India. Usually, Indian robins and fan-throated lizards don’t pay much attention to each other. Here’s a video in which a lizard displays when a pair of robins pass by. His dewlap remains extended for a while, which is uncharacteristic, but the interaction doesn’t escalate:

But in the same population, an Indian robin chases after a male fan-throated lizard, after the lizard first ran in the direction of the robin. He starts perched on the rock in the centre of the screen. Here’s a video, slowed down to half-speed. When filming,  I had no idea what was happening, or even where the lizard was, which explains why the camera deviates from the lizard for a while (apologies). 

I’m not sure what’s going on. I didn’t think robins eat lizards–do they? Maybe it thinks the lizard’s tail is a worm? Maybe it’s just playing? Any further ideas?

Spotlight on Cuban Anoles III: Anolis vermiculatus

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I don’t think I’ll run into any disagreements by claiming that Anolis vermiculatus is hands-down one of the coolest anoles in existence. First of all, it’s huge – up to 123mm SVL for males. They have blue eyes. They are capable of eating fish and amphibians. They can run across water, and are “truly aquatic” (Schwartz & Henderson 1991). The males in particular seem more like crested water dragons than anoles. A. vermiculatus is sometimes called “lagarto caiman” in Cuba. Although this might bring to mind Dracaena for some, Anolis vermiculatus is quite a different animal. Nevertheless, the name seems appropriate after meeting the creature.

We got our first chance to see A. vermiculatus while staying in Viñales, a lovely, foggy town surrounded by towering limestone mogotes home to Anolis bartschi. We had originally expected to see them only in Soroa, a legendary locality for Anolis in Cuba and a short drive from Viñales. However, we discovered them in abundance along the densely vegetated banks of the mud-brown stream running between our hotel and the road.

A blue eyed male Anolis vermiculatus

A blue eyed Anolis vermiculatus

I generally found A. vermiculatus to be the hardest lizard to get a decent picture of that we encountered (with nods to A. equestris and A. vanidicus). Their preferred habitat is full of shade, and A. vermiculatus is quick to retreat there, often spotting clumsy humans from long distance. If molested further, they leap into the water and apparently remain submerged for some time.

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The next day, we were scheduled to have an hour in Soroa, but a bus breakdown allowed us two entire hours. We found more A. vermiculatus, a bit more light, and much clearer water, but the lizards remained a wary bunch. Below are females and a juvenile rafting in what looks like a coconut husk. Sexual dimorphism in this species is significant for size (123mm max SVL for males, 83mm for females, Schwartz & Henderson 1991), and coloration.

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_1060181

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I did get the chance to photograph two large males. This individual appears to have some sort of parasite (notice the swelling on the side of the neck). Anyone have any ideas what it could be? My guess would be a nematode. I’m unsure if the deformity of the jaw is another of these parasites or perhaps a different injury.

_1060256

Although A. vermiculatus is able to run across the surface of water, we did not observe this behavior in our short time with the species. However, it was quite surprising to learn that these lizards do this without the assistance of toe fringes as in Basiliscus.

Here’s the best shot of the bunch:

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Next up: a blue lizard that wears yellow pants!

New Film on Snake Research: Do the Lizard Cameos Steal the Show?

httpv://www.youtube.com/watch?v=zDtDtn5n8-A

A new movie on snake research, an Alex Pyron production, features not only great snake footage, but cameo appearances by anoles and Frank Burbrink explaining how he got out of prison and into herpetology (see disclaimer below), as well as wildfires in the Brazilian Cerrado, and plenty of other frogs, lizards, and rock and roll music.

Alex explains: “Most people think of science as being fairly boring most of the time. They are probably right. However, readers of this page are more likely familiar with another side of the story. Those of us who do field work are lucky enough to get paid to flip rocks for a living, chasing after the most exciting creatures on the planet. Books like Snakes and Snake Hunting and The Snake Charmer captured some of this adventure, and gave many of us an early glimpse into the future careers that awaited us. Bringing this magic to the silver screen is snakehandlers: these signs shall follow them, the new documentary about field herpetology that you never knew you needed (or wanted).

Shot across one year, snakehandlers follows Alex Pyron and a rotating band of pirate misfits across the U.S., Panama, Ecuador, and Brazil in search of tissue samples from the rarest (and commonest) herps around, to fuel the fires of our phylogenetic frenzy. Along the way, a wildfire rips across the Brazilian Cerrado, the clouds boil in the Northern Andes, Frank Burbrink shares his hard-luck tale of crime and punishment on the road to redemption from state prison to evolutionary biology*, famous herpetologists from the past speak to us across time, and new species are discovered left and right.

At its core, snakehandlers tries to answer the question of why we work with snakes to begin with. Herpetologists from every corner share their stories about the interests and experiences that brought them into the field. On the whole, though, the question remains unanswered; how could it be? Why do we do something as crazy and absurd as handle snakes or chase anoles? Watch snakehandlers and see if you can figure that out for yourself, in a movie that does for snakes what Plan 9 did for Outer Space.

As a plus (or a main attraction) for readers of Anole Annals, have fun spotting at least six species of Anolis from North, Central, and South America! Happy herping…

*The producers of snakehandlers were unable to verify the accuracy of all participant interviews.”

Fluorescent Lizard Skeletons Used to Precisely Measure Growth

Several weeks ago, Anole Annals highlighted a recent paper that uncovered the molecular bases of craniofacial dimorphism in the carolinensis clade of Anolis lizards (for full disclosure, I am the lead author of that paper). Hidden deep within that research is a relatively new technique for precisely measuring rates of skeletal growth that may be of interest to the community. I briefly introduced this technique several years ago in a post about methods of skeletal preparation, but with the details of this method now available it is worth highlighting once more.

Double labeled facial skeleton of A. carolinensis. Green label (calcein) and red label (alizarin complexone) separated by 30 days.

Because some images shouldn’t be lost in the supplementary materials. Double labeled facial skeleton of A. carolinensis. Green label (calcein) and red label (alizarin complexone) separated by 30 days.

Growth in body size can often be measured using calipers or a ruler. But in some situations a finer-scale analysis may be necessary, such as when differences in growth rate may be subtle, within the range of error associated with those manual methods. Fluorescent calcium chelators provide the precision needed to measure differences on the order of microns per day. In the recent paper, this technique was used to measure facial elongation in sexually mature green anoles, which was only ~8um per day in males and ~4um per day in females. These compounds are stable, are not highly toxic to animals, are relatively inexpensive, and can be easily used in the field or the lab. They can also be applied to adults or hatchlings with little modification to the protocol as injection volumes are typically 10-20ul depending on size. Ultimately, there is a lot of versatility to the way in which this method can be applied.

Dimorphism in facial growth rates between male and female A. carolinensis. Modified from Sanger et al. 2014.

Dimorphism in facial growth rates between male and female A. carolinensis. Modified from Sanger et al. 2014.

While new to herpetology, this technique was adopted from the biomedical literature on fracture repair where precise spatiotemporal measure of bone deposition is required. The general experimental framework is that pulses of chelators with different fluorescent properties are delivered at distinct intervals, the skeleton prepared, and the distance between the labels recorded from digital photographs. Calcium chelators are available that fluoresce under many of the standard filters used in modern microscopy – including green (calcein), red (alizarin complexone), orange (xylenol orange), and blue (calcein blue and oxytetracycline) – offering great experimental flexibility. Once incorporated into the bone, their signature remains strong for at least 30-45 days, until it is remodeled away as the living skeleton continues to grow and reshape itself. In the recent paper on craniofacial dimorphism, fluorescence in the facial skeleton could be observed following simple removal of the skin because the face has little to no overlying connective tissue. Measuring growth of the vertebrae or limbs is also possible, but may require careful sectioning of the bone using either plastic or paraffin protocols. Ultimately I think that there is a lot of potential with this method that has yet to be explored in the context of organismal biology. I hope that by highlighting this method here more people become aware of its utility and give it a try.

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