Anole Annals

AA readers may recall a series of post this past May, in which I discussed research on anole ecology and evolution in the Bahamas. Those posts discussed studies that have been ongoing in Abaco for several years on the effect of predators (curly-tail lizards) on anoles, as well as studies initiated this year to the south in Staniel Cay.

Hurricane Irene, predicted to reach Category IV status, is now bearing down on the Bahamas from the south. And if you examine the hurricane’s track, you’ll see that she is aiming right at our study sites. What will happen? In the past 13 years, we’ve had three experiments terminated by hurricanes. Please cross your fingers, toes, and any other extremities in hopes that fourth time is a charm.

Not Your Typical Genome: Homogeneous Anole Genome Lacks Isochores Common in Other Amniotes

By Rich Glor

On August 23, 2011

In Anole Genome Research, New Research

Figures from Fujita et al. illustrating relative homogeneity of GC content across the anole genome (left) and shifts in GC3 along branches in the vertebrate tree, with black branches indicating descreases of GC3 and gray branches indicating increases of GC3 (right).

Genomes are rarely homogeneous aggregations of Gs, As, Ts, and Cs. Indeed, variation in basepair frequency can have important implications for how genomes, and the organisms they generate, evolve. Regions with relatively homogenous GC content that extend for more than 300 kb known as isochores are prominent features of previously sequenced amniote genomes. Isochores are associated with a range of important variables, including gene density, intron length, DNA replication timing, and gene expression. GC-rich isochores also tend to experience high rates of recombination, resulting in elevated effective population sizes and increased efficiency of purifying selection relative to drift.

Teaching With Anoles, Part 2 (Fifth Grade Edition)

By mjohnson216

On August 23, 2011

In Education and Anoles

A fifth grade teacher prepares for a lizard sprint trial. (Notice the two different perches in the cage in the foreground.)

A few days ago, I posted a description of an anole-based project I assign in my college Evolution course, but of course, anoles are fascinating to students of all ages! In this post, I’ll describe materials I developed this summer as part of Trinity University’s Science Teaching Institute, teaching 20 San Antonio fifth-grade science teachers to use green anoles (Anolis carolinensis) in their classrooms. These materials were specifically designed to meet Texas Essential Knowledge and Skills (TEKS) standards, but I expect they would be appropriate for many elementary school science classes.

A Little Worm “Told” Us …

By Gerrut Norval

On August 22, 2011

In Introduced Anoles, New Research

Studying the brown anole (Anolis sagrei) in Taiwan has presented me with numerous new opportunities, one of which is an introduction into parasitology.

A Kiricephalus pattoni nymph under the skin of a female brown anole (Anolis sagrei), collected in southwestern Taiwan.

The first parasites I found in A. sagrei in Taiwan were relatively large worm-like parasites that are often visible as a lump under the skin of the lizard. Unfortunately, my first samples were lost by the person I had sent them to for identification. But luckily, I found some more, and with the assistance of C.R. Bursey and S.R. Goldberg, the parasites were identified as the nymphs of the pentastome, Kiricephalus pattoni. Together we reported A. sagrei as a new host of this parasite in Taiwan (Norval et al., 2009).

50th Anniversary of Ecomorphology

By Jonathan Losos

On August 22, 2011

In Classics from the Literature

The field of anole ecomorphology was born 50 years ago this month when Bruce Collette published his pathbreaking paper, “Correlations between ecology and morphology in anoline lizards from Havana, Cuba and southern Florida” in the Bulletin of the Museum of Comparative Zoology. It was this paper that first explicitly detailed the relationship between morphology and habitat use in Anolis lizards and this was the start of the research program of Rand, Williams, Schoener and others that today has made Anolis a textbook case of ecomorphological diversification. Indeed, because the term “ecomorph” itself can be traced to Ernest Williams’ classic 1972 paper (see p.56 of Lizards in an Evolutionary Tree), in many respects, this month represents an important landmark in the development of the field of ecological morphology.

So, what did the paper say? The summary says it all: “This paper has attempted to correlate ecology with morphology in six species of Anolis from southern Florida and Havana, Cuba. It is felt that with proper ecological data, valid correlations can be made that can lead to an appreciation of the significance of characters often used in taxonomic analysis. Also, light is shed upon the structural adaptations that allow related sympatric species to occupy the same geographical area without facing deleterious competition. It has been shown that selection has acted so that lizards will usually match the color of their natural background. Examples have been shown to support the idea that peritoneal pigmentation is connected with exposure to radiation. The value of long legs to terrestrial lizards has been shown. Short relative tail length has been correlated with arboreality. The more arboreal members of a group of sympatric species have been shown to be larger and have more lamellae than terrestrial species. Data have been presented to support the contention that increased numbers of lamellae are an adaptation to increased arboreality.”

And who was this Bruce Collette?

Here’s A Man Who Loves Green Anoles

By Jonathan Losos

On August 20, 2011

In All Posts

and who doesn’t?

http://dusttracks.com/2011/08/20/the-green-anole-is-the-hero-the-sweet-tea-is-the-salvation/

Teaching With Anoles, Part 1

By mjohnson216

On August 20, 2011

In Education and Anoles

As the summer is ending and a new semester is beginning, your thoughts may have returned to teaching. I try to use a diversity of taxonomic groups in my lectures and labs, but of course, I find anoles to be useful examples for many topics in the classroom. In my Evolution course, taught each year to biology majors at Trinity University, I focus one laboratory module on anole evolution to teach my students to conduct phylogenetically-informed comparative analyses. Below, I’ll describe the approach I use in my course, and if you would like to see my materials, or adapt them for your own teaching, I’d be happy to share the lab handouts – just email me at michele.johnson[at]trinity.edu.

Many activities in my lecture and lab focus on creating and interpreting phylogenies, and one of my earliest lab sessions teaches students to use parsimony and similarity-based classification to build phylogenies from mammalian morphological traits.

A New Anole — Anolis Lunalis?

By Allison DeVan

On August 19, 2011

In Anole Art, Literature, and Humor

Growing Limbs – But Not the Kind With Leaves.

By Thomas Sanger

On August 18, 2011

In New Research

Stages of limb development for A. sagrei

As lineages rapidly diversify, such as in the history of anoles, does their developmental-genetic architecture constrain the rate or direction of evolutionary change? In other words, could the processes controlling the production of variation, the variation that natural selection acts on, affect patterns of phenotypic evolution by generating some phenotypes more readily than others? While theoretical discussions like these have been prevalent for over a century, developmentally-based constraints were not formalized in the context of modern biology until the 1980’s, fueled by an influential paper by Maynard-Smith and colleagues and the re-synthesis of evolutionary and developmental biology. Since then evo-devologists have been testing the plausibility of developmental constraints by examining the developmental bases of traits that have independently evolved multiple times; phenotypes that have repeatedly evolved using the same mechanisms may be indicative of constraint (because the precise interpretation of these patterns and appropriate level of analysis are contentious I will leave further theoretical discussion of constraint to future conversations).

In a recent paper, for which I am the lead author, we set out to examine whether developmental constraints could have affected diversification of anole limb morphology.

Dominican anoles that bask together, stick together

By Martha Muñoz

On August 17, 2011

In Natural History Observations, Notes from the Field

I am irreparably fond of anoles, but I must admit that they are not the cuddliest of beasts. In fact, they can be downright unfriendly, especially with each other. The mere sight of another male sends anoles into spasms and, when not mating, males and females seem to barely tolerate each other, at best. It would seem that cuddling is best left to mammals and birds, but recent observations would indicate that even the ornery anole has a soft side.

Anolis shrevei mating pair cuddling in Valle Nuevo, Dominican Republic.

A post by Kat Wollenberg on this blog documented two Anolis etheridgei sleeping with their tails intertwined. A follow-up post by Melissa Woolley shows that Anolis gemmosus mating pairs sleep near each other, even if not touching.

But does an anole have to be asleep to show its softer side? In June 2011 I observed an Anolis shrevei mating pair in Valle Nuevo cuddle as they basked one afternoon. It is chilly at 2500 meters, even in the Dominican Republic. It had been a cold morning, and neither the sun nor the lizards had shown themselves until almost noon. But when the sun did peek out from behind the clouds, there was a mass exodus of anoles, which came out from under their rocks to take advantage of the day’s first rays. This little pair came out from under the same rock and sat together for close to an hour. They were touching each other, despite the fact that there seemed to be enough rock to go around. Whether this was coincidence or another mechanism of behavioral thermoregulation, the anoles of the chilly Cordillera Central know how to keep warm.