Tag: Anolis carolinensis Page 2 of 3

Evolution 2016: Polar Vortex Revisited

On June 23, 2016

Shane Campbell-Staton giving his talk at Evolution 2016

We’ve heard about the effects of polar vortexes here on Anole Annals before. The infamous 2013/2014 event brought record-breaking snow and low temperatures to the Southern U.S., leaving people and animals both a little chilled. This created the perfect opportunity for Shane Campbell-Staton to investigate the effects of such extreme events on thermal tolerance of the native Carolina Anole, Anolis carolinensis. Shane also spoke about this at SICB earlier this year, and AA contributor Martha Muñoz covered the talk pretty thoroughly here on Anole Annals. Nevertheless, I’ll summarize some key points here in case you missed it.

An unlucky lizard during the polar vortex snow storms in the South.

Shane got lucky in the sense that he had measured thermal tolerance in August 2013 for populations affected by the polar vortex, 5 months before the event. Typically, the cold arctic air is tightly constrained around the North pole, but periodically the boundaries weaken and the cool air expands southward. These events are not regular, so Shane had no idea one was coming that winter or that it would extend so far south. It was serendipitous that his study populations, 3 in Texas and 1 in Oklahoma, were impacted by the extreme weather event. This species, particularly in the Southern portion of its range, is not used to low temperatures and reports came in of anoles dying off during the storm.

Air temperatures for January 5-7, 2014, compared to the 1981-2010 average. Map by NOAA Climate.gov

So Shane returned in August of 2014 and sampled again, curious as to how this cold impacted thermal tolerance. He found that tolerance to low temperatures, measured as critical thermal minimum (CTmin), was lower in some populations after the event! Even more, the difference was greatest in the Southernmost population (Brownsville, Texas). Shane returned again in the fall of 2014 to see if this effect persisted or if it was simply a plastic response to the event. He found that the populations sampled in 2014, and presumably their offspring, still had lower critical thermal minimums. This result suggests that the extreme cold weather had caused an evolutionary shift in cold tolerance via natural selection: only the animals that could tolerate the cold temperatures survived and passed on their cold-tolerance genes. Shane went on to conduct a common garden study to verify that the trait was not simply a plastic response. He found that the lower CTmin persisted in lab-reared animals: strong evidence that these shifts had a genetic basis.

Lastly, Shane looked at the functional genomics of cold tolerance. Using liver tissues to obtain transcriptomes (representing expressed genes), he found several gene modules associated with thermal tolerance including some associated with respiratory electron transport chain, lipid metabolism, carbohydrate metabolism, and angiogenesis/blood coagulation. He also found that the gene expression patterns in the Southern populations affected by the storm resembled the Northern populations that more regularly experience cool temperatures, indicating a common genetically based adaptive response across populations.

Evolution 2016: Genomic Insights into Anolis carolinensis Phylogeography

By Kristin Winchell

On June 19, 2016

In New Research

Anoles, in particular Anolis carolinensis, have long been considered an ideal group for studies investigating thermal physiology, reproductive endocrinology, and even regeneration. With the recent publication of the A. carolinensis genome (see AA posts on this here and here), the possibilities for new genomic studies in this new model species have significantly increased.

Joseph Manthey and co-authors used this new resource to clarify the phylogeographic relationships of A. carolinensis. Previous research on the phylogeography of A. carolinensis using both mitochondrial DNA and nuclear DNA showed that there were 5 clades. However, the relationships between these groups differed between the two approaches. Joseph looked at the genomes of 42 individuals from 26 localities across the native range to determine the true evolutionary relationship between regional groups and to shed light on the demographic histories of the groups. Manthey sequenced 500 loci using an anchored hybrid enrichment approach.

STRUCTURE analysis showed that the clusters had little admixture

Manthey et al. found that the genomic data predicted 5 genetic groups, in agreement with both the nuclear and mitochondrial analyses previously done. Their results also indicated that the 5 genetic clusters were distinct with little admixture. However, the relationships between groups did not agree with either the mitochondrial or nuclear trees, yet all nodes had extremely high support (93-100%)

Finally, Manthey commented on the likely timing of this diversification and associated demographic trends. Their results indicate that the initial split occurred during the late Miocene or early Pliocene and that the remaining diversification occurred during the Pleistocene. They also found that the most Southern population had a significant number of fixed genes while other populations did not. This suggests that this group was likely the oldest and most stable and supports an “out of Florida” hypothesis of diversification.

Decoupled Muscle Activity and Kinematics in Green Anoles (Anolis carolinensis): New Research by Kathleen Foster and Tim Higham

By Kathleen Foster

On March 26, 2014

In New Research

Anolis carolinensis. Photo taken by Kathleen Foster.

Anoles are the indisputable poster children of ecomorphology. Morphological, behavioral, and performance data support classification of Anolis species into discrete ecomorphs on the Greater Antilles islands. In a large part, the basis of this classification is due to variables (e.g. limb length) that relate to differing locomotor abilities (i.e. speed and/or stability) on the various substrates that comprise the different areas of the arboreal habitat. However, until recently, we knew nothing about how the muscles that power locomotion in these species relate to their ability to cope with the challenges of moving in these different microhabitats.

In a recent paper in Proceedings of the Royal Society B, we used a combination of electromyography and 3D high-speed video to examine the impact of perch diameter and incline on limb kinematics and muscle activity in Anolis carolinensis. Our previous study in the Journal of Experimental Biology found a number of kinematic changes (e.g. increased limb flexion and depression) associated with increased stability on narrow surfaces, and we hypothesized increased recruitment in the muscles associated with those movements. Interestingly, this was not the case. Despite considerable kinematic modulation with change in perch diameter (63% of the 32 kinematic variables were significantly affected by perch diameter), there was very little change in muscle activity (2% of the 100 muscle activity variables). This decoupling of kinematics and muscle function raises a number of very interesting questions relating to the sensitivity of these muscles to changes in operating length and the degree to which this species is specialized for a particular microhabitat. It also highlights the complexity of the physiological basis of animal locomotion and emphasizes the need for caution when attempting to infer motor control from kinematics and vice versa.

An additional result that may significantly impact identification of habitat preference in Anolis lizards relates to the importance of variability, as opposed to magnitude, of muscle activity in describing the differences in how this species handled the different substrate conditions. Specifically, the muscles examined were less variable on the broad perch compared to the narrow perch and on the vertically, as opposed to horizontally, inclined perch. Locomotor stereotypy is generally believed to reflect locomotor specialization, although reduced variation of in muscle activity may also be achieved as a byproduct of near-maximal muscle recruitment. However, we have little support for this second option, as the muscles were neither approaching maximal stimulation nor vastly different in overall magnitude or recruitment. Therefore the greater stereotypy of muscle activity seen in the green anole as it moved on the broad, vertical condition may reflect a physiological preference for tree trunks, rather than the narrower and shallower substrates that comprise (on average) the trunk-crown region to which it is traditionally assigned.

It is clear that there remains a wealth of knowledge waiting to be unearthed in the Anolis system and this paper barely scratches the surface. It emphasizes how little we understand about the complex nature of animal locomotion and the relationship between the muscles that power locomotion and the movements we observe in the field. And the possibility that variability of muscle activity might be a useful tool to identify functional preference for microhabitat is tantalizing and deserves further attention, especially if it can be applied usefully to mainland Anolis species. The remainder of my dissertation will focus on fleshing out these and other aspects of muscle function through the comparison of ecomorphs of the Greater Antilles.

Kathleen L. Foster & Timothy E. Higham. (2012). How forelimb and hindlimb function changes with incline and perch diameter in the green anole, Anolis carolinensis. Journal of Experimental Biology 215: 2288-2300. (DOI: 10.1242/jeb.069856)

Kathleen L. Foster & Timothy E. Higham. (2014). Context-dependent changes in motor control and kinematics during locomotion: modulation and decoupling. Proceedings of the Royal Society B 281: 20133331. (DOI: 10.1098/rspb.2013.3331)

Fill In The Blank: Obscure Anole Life History Traits

By Andrew Durso

On June 27, 2013

In Ask the Experts

In collaboration with the Conservation Biology course taught by Dr. Karen Beard here at Utah State University, where I am a Ph.D. student, I have been involved in gathering life history data on ~400 species of reptiles that have been introduced outside of their native ranges for an analysis of how life history traits (e.g., diet, fecundity, longevity) interact with other factors to influence the likelihood of successful establishment. Appendix A of Fred Kraus’ 2009 book Alien Reptiles and Amphibians is the source of the species list we are using, and included in this analysis are 26 species of Anolis. This is where you come in.

First, we coded all anoles as (i) sexually-dichromatic, (ii) diurnal, (iii) non-venomous, (iv) oviparous, (v) omnivores that lack (vi) temperature-dependent sex determination and (vii) parthenogenesis. Is anyone aware of any exceptions to these seven generalizations?

Second, we searched for data on clutch size, clutch frequency, incubation time, and longevity. The Anole Classics section of this site and the Biodiversity Heritage Library were particularly useful. After conducting what I feel to be a pretty thorough literature scavenger hunt, I am forced to conclude that some of these data simply do not exist at the species level for all of the species we’re interested in, or are not explicitly stated in a way that is obvious to a non-anole-expert. Of course, there is a lot of literature, including many books that I don’t have access to, and there are also lots of credible observations that don’t get published. I’m hoping that some of the readership here can help fill in at least some of the blanks in the table below. As one member of the team, I did not collect all of the data that are filled in myself, nor have I personally vetted every value, so if you spot an error please do point it out.

Two important points:

Many environmental factors obviously influence the life history parameters of our beloved and wonderfully plastic reptiles, so we appreciate that many of these values would be better represented by ranges and are dependent on latitude, altitude, climate, and many other factors. Where a range is published, we are using its median value.
I should also emphasize that, because of the large size of this study and the diversity of taxa included (ranging in size from giants like Burmese Pythons, Nile Crocodiles, and Aldabra Tortoises to, well, anoles and blindsnakes), it is more important for the data to reflect the relative values of these life history parameters across all anoles (and all reptiles) than it is to specifically and precisely represent all known variation within a given species of anole.

Without further ado (for your enjoyment, and because I know from my own blog that nobody reads posts lacking pictures, I’ve embedded an image of each species):

Species	Median clutch size	Median clutches per year	Incubation time (days)	Maximum longevity (months)
A. aeneus	2
A. baleatus
A.bimaculatus	2		43	84
A. carolinensis	1.15	6	41.5	65
A.chlorocyanus	1	18
A. conspersus	1
A. cristatellus	2.5	18		83
A. cybotes	1	18	45
A. distichus	1	16	45.5
A. equestris	1	1	48	149
A. extremus
A. ferreus	1	18
A. garmani	1.5	18	67
A. grahami	1
A. leachii
A. lineatus
A. lucius	1	3.5	60
A. marmoratus	2		50
A. maynardi
A. porcatus	1	18	63.5
A. pulchellus	1
A. richardii	1
A. sagrei	2	20	32	22
A. stratulus
A. trinitatis	2		50
A. wattsi	1

Thanks in advance. I think this is a great blog and I hope to post something more interesting on here soon.

Flexible Perches… Who Cares?

By Casey Gilman

On March 4, 2013

In New Research

httpv://www.youtube.com/watch?v=5Yk4szOOaFg

I had spent a summer in Florida watching green and brown anoles jump around on trunks and branches, and I was amazed by how well they appeared to navigate their habitat, despite the variable flexibility and complexity of the habitat. Many anole species jump. They jump to move around their habitat, to forage, to fight, to chase (or be chased by) potential mates, and to avoid predators. If you have observed anoles jumping in the wild, you might notice that some species jump a lot, and they jump to and from a lot of different types of structures (the ground, trunks, branches, leaves). While the diameter of different types of structures has been shown to affect running speed and surefootedness, it has also been shown to have little impact on jumping, at least in the lab. But what about the flexibility (compliance) of the structures they are jumping to and from? Will a narrow branch in the wild affect jumping performance, not because of its diameter, but because narrow branches tend to be flexible? What about other flexible structures in nature, such as leaves, which tend to be wide and highly flexible? And, are anoles choosy about where, and from what, they jump?

It turns out, when it comes to jumping, perch flexibility is quite important.

With the help of my advisor, an engineer, and a generous collaborator who gave me guidance and let me use his specially-designed anole jumping tank, we conducted a lab study to to determine if and how perch flexibility affects jump performance in green anoles. We found that the more flexible a perch was, the more it negatively affected jump distance and jump speed. We also observed that the recoiling perches whacked the anoles in the tail as they were jumping, which caused many anoles to do an impressive faceplant (this part of the story has received a bit of notoriety, both in the Annals (twice) and elsewhere). So, increased perch flexibility decreases jumping performance in the lab. But what does this mean for those anoles I’ve seen jumping from leaves and twigs in their natural habitat?

Male green anole perched on a flexible palm leaflet

To answer this question, I headed back down to Florida and spent a little over a month filming green anole jumping behavior. The green anoles I observed in the wild appeared to be extremely choosy about which structures they jump from. While I found them basking and foraging on a range of perches, from stiff trunks to highly flexible leaves, the lizards would generally jump from the sturdiest perches in the habitat. If they were on a thin and flexible palm leaflet, they would move closer to the base of the leaflet to a stiffer spot before jumping. And when they did jump from highly flexible perches, they jumped to another perch that was just a short distance away. The longest jumps we observed were from the most sturdy (and low-lying) perches.

The green anoles I observed appeared to be so good at choosing perches to jump from, that over the course of my study I only noted two failed jumps from flexible perches. In one instance, a male was perching near the end of a leaflet, then moved to a sturdier part of the leaflet to jump onto a perch above him. Although this part of the leaflet was sturdy, it was not sturdy enough. The force of the jump pushed the jump perch down away from him, and he was unable to jump high enough to reach his intended perch. Luckily, he was able to catch onto another leaflet before he hit the ground. In the other instance, another male attempted a jump to a far perch and landed on the ground instead, then quickly climbed back up the palm. However, because I documented undisturbed behavior, many of the jumps I witnessed were sub-maximal. The lizards were jumping as far as they needed to at the time to get to another perch, but were not attempting to flee and therefore may not have been jumping as far as they might otherwise been able to. I wonder how my observations of how choosy they are with jump perches would change if they were in situations where they needed to escape quickly.

Shelby Prindaville’s Anole Artwork

By SPrindaville

On November 18, 2012

In Anole Art, Literature, and Humor, Anoles in Commerce

Watercolor drawing by Shelby Prindaville

Shelby Prindaville, Polychrotidae (Heatstack) detail, watercolor and pencil on paper, 30×22″, 2011

My watercolor drawings and figurative sculptures feature a variety of Anolis lizards. The visually fascinating characteristics of anoles combined with their small size yet reptilian “otherness” (occupying a middle ground between too-easily-anthropomorphized mammals and too-alien fish or invertebrates) make anoles an ideal animal representative for my broader ecological interests.

Shelby Prindaville, Anolis proboscis (Pair), watercolor, 3P art medium, and pencil on translucent paper, 16×24″, 2012

The drawings and sculptures I create with anoles use their innate character and abilities to explore a purgatorial space. The first drawing in the watercolor series puts anoles in place of rats in the rat king myth made famous in The Nutcracker; the use of anoles allows a way out of the diseased mass through voluntary autotomy and allegorically demonstrates that repairing environments requires sacrifice. Other drawings pull from subjects ranging from the Ouroboros to Terry Pratchett’s allegory of summer.

Shelby Prindaville, Anolis carolinensis and Mimosa Pudica (Falling), watercolor and pencil on velvet paper, 27×19″, 2012

My desire to sculpt small yet still anatomically accurate anoles has actually led to the development of a new polymer medium: 3P QuickCure Clay. I collaborate with LSU Chemistry Professor John Pojman and his company 3P, and my suggestion to create a clay and its subsequent development has allowed me to use a batch-curing process that achieves the intricately detailed results below.

Shelby Prindaville, Polychrotidae (Dive and Climb), 3P Clay, 4x8x2.5″, 2012

To see larger images or more of my artwork, please visit shelbyprindaville.com.

Cleaner Birds Removing Parasites From Anoles?

By Jonathan Losos

On October 9, 2011

In Natural History Observations

Here's a photo of a Carolina Wren that's caught a brown anole. But this story is something different. Photo from http://www.flickr.com/photos/24073599@N05/4545405419/

Brian Langerhans, he of mosquitofish fame (but with some anole credentials, such as here and here), writes from Raleigh, NC:

A strange interaction was observed this morning and I’m wondering if you know what’s going on. There are a number of A. carolinensis that live around our house, and today something weird happened. It’s a pretty cool morning, but a big male was on a ledge on our porch. Two Carolina wrens flew over to the anole, the anole sat still while one pecked on it’s body and tail, and then extended it’s dewlap and opened it’s mouth for a while (but was otherwise still) as the other wren pecked around and in it’s mouth. Do you know what might have been happening here? You’d think the birds were harrassing the anole (and maybe it’s too cold for the lizard to fight back), but it didn’t seem like it. There’s no way they could have been cleaning it (like removing mites), right? Any thoughts?

What’s All the Fuss About Dewlaps?

By Jonathan Losos

On October 8, 2011

In New Research

: Anolis carolinensis from http://www.mascotissimo.com/wp-content/uploads/2008/02/anolis_carolinensis.jpg

A few years ago, Richard Tokarz and colleagues conducted a series of studies in which he surgically disabled the dewlaps of some male A. sagrei and discovered that these functionally dewlapless lizards had no trouble holding a territory and seducing females. In a new study, Henningsen and Irschick found that surgically reducing the size of dewlaps in male A. carolinensis by about one-third had no effect on male-male aggressive interactions in the lab. Makes one wonder what’s the big deal about having a dewlap.

Jack Frost Nipping At My Embryos

By Chad Watkins

On October 4, 2011

In Natural History Observations, Notes from the Field

My first thawed hatchling, Mr. Freeze, moments after emerging with the desire to rule the world (as soon as he got a little extra warmth from my finger)

Two weeks ago our building decided to test its emergency power generators. They assured us there should be no problems (never the case) and that electronics plugged into emergency wall sockets shouldn’t have a disruption in power while others might experience small outages that evening.

We assumed our incubator was in the emergency socket and had little concern to think that any disruption to power would cause problems. Needless to say, that was not the case. There was a surge when the power came on and according to the repair tech it fried 2 boards… however when power was restored instead of returning to its preset temp, room temp, or even remaining off, it decided to turn on and drop the temp to freezing (or below) (we are unsure of the exact temp as the display board was one of the 2 that fried). Everything inside was covered in frost and ice including the few remaining eggs I decided to spare from embryo extractions and allow to hatch for breeding next year.

Perch Compliance and Dumb Luck

By Casey Gilman

On September 26, 2011

In New Research

Thanks to Duncan Irschick’s insistence that I start a project immediately upon my arrival in the PhD program at UMass, Amherst (and inspiration from a passage in Lizards in an Evolutionary Tree stating that the effects of perch instability on anole locomotion had not yet been examined – thanks, Jonathan!), I spent part of the summer of 2011 studying the effects of perch compliance (flexibility) on green anole ecology and jumping performance in the wild. This followed my examination of the effects of this perch characteristic in the lab over the last two semesters (manuscript under review).

However, finding an ideal field site for this study proved a bit more challenging than I had anticipated. Yoel Stuart invited me to work with him on a project examining the effects of interspecific competition on diet in Anolis carolinensis and A. sagrei using stable isotope analysis last summer (we continued this project through 2011), and I based my vision of an ideal field site on my experiences watching green anoles hop and run around on slender (and quite flexible) mangrove branches. I envisioned a site with plenty of small to medium diameter branches and larger trunks for the anoles to frolic on, which would provide me with plenty of data on how these lizards use compliant perches in the wild.

After a FULL week of searching (with plenty of field site advice from Yoel), I settled on a site with the type of habitat structure I had originally been seeking, as well as many small cabbage palms (< 3m) along the forest edges.